Neurology

Multiple sclerosis (MS) is a complex, chronic immune-mediated disease of the central nervous system characterized by focal inflammation, demyelination, and neurodegeneration. Magnetic resonance imaging (MRI), first incorporated into the McDonald Criteria for the diagnosis of MS in 2001, is an integral tool in the diagnosis, prognosis, and therapeutic monitoring of people with MS (PwMS).¹

MRI research in MS is rapidly expanding and offers insights into the pathophysiology of MS with important implications for the routine clinical care of PwMS. At the Consortium of Multiple Sclerosis Centers 2024 Annual Meeting, the US Department of Veterans Affairs (VA) MS Centers of Excellence hosted an educational symposium highlighting MRI biomarkers in MS, including T2-lesions, chronic black holes (cBHs), brain atrophy, paramagnetic rim lesions (PRLs), and the central vein sign (CVS). The symposium also provided a brief overview of quantitative MRI techniques used to characterize MS lesion severity and research applications of these techniques. This clinical review summarizes the main points of that symposium with the goal of introducing key concepts to federal health care practitioners caring for PwMS.

MRI Biomarkers in MS

T2-lesions, Chronic Black Holes, and Brain Atrophy

Focal immune-mediated inflammation and demyelination in MS may be detected by MRI as hyperintense foci on T2-weighted (T2-w) imaging (eg, T2-w turbo spin echo or T2-w fluid attenuated inversion recovery sequences). These T2-lesions, critical for diagnosing MS, are typically ovoid and occur in the periventricular, juxtacortical, infratentorial spinal cord white matter (Figure 1A). T2-lesion number and volume show some association with disability and optic nerve.

Wattjes et al highlight 2 cases to demonstrate this point: a man aged 52 years with MS for 23 years and a woman aged 50 years with MS for 11 years. Despite having MS for a much shorter duration, the woman had worse disability due to a higher lesion number and volume.² T2-lesion volume also impacts disability progression in PwMS. Gauthier et al compared the probability of progression in 3 women, all of whom were aged 39 years and had MS for 6 years. The profile with highest probability of disability progression had the highest quartile of T2-lesion volume.³ T2-lesion volume over 2 years correlates with worse scores on disability metrics such as the MS functional composite, paced auditory serial addition task, and brain volume.⁴ A 2024 systematic review and meta-analysis demonstrated that T2-lesion volume is significantly correlated with clinical disability in PwMS.⁵

 

Select T2-lesions are also hypointense on T1-w spin echo images and are known as cBHs (Figure 1B). Histologically, T2-lesions with cBHs have more severe architectural disruption than those without cBHs.⁶ cBH number and volume are significantly correlated with disability, regardless of the degree of hypointensity on T1-w imaging.^5,7 A 10-year longitudinal study demonstrated that cBHs were associated with disease progression after 5 years while T2-lesion volume was not, indicating that cBHs may be a more accurate predictor of disability.⁸

Brain atrophy, another imaging biomarker of MS, affects both the cerebral white and gray matter. White matter fraction (the volume of white matter relative to the intracranial compartment volume) and gray matter fraction (the volume of gray matter relative to the intracranial compartment) are significantly lower among PwMS compared with healthy controls. In addition, gray matter fraction is lower among patients with primary and secondary progressive MS compared with those with relapsing-remitting MS, clinically isolated syndrome (CIS), and radiologically isolated syndrome (RIS). Gray matter fraction is also correlated with several motor and cognitive disability indices.⁹

Paramagnetic Rim Lesions

Neurologic worsening in PwMS occurs by 2 distinct mechanisms: relapse-associated worsening, a stepwise worsening of symptoms due to incomplete recovery following a relapse; and progression independent of relapse activity (PIRA), which is an irreversible neurologic deterioration in the absence of clinical or radiological relapses.¹⁰ PIRA is associated with neurodegeneration and predominates in both primary and secondary progressive MS. However, recent data demonstrated that PIRA may contribute to as much as 50% of disability worsening in relapsing MS and occurs early in the RMS disease course.^10,11 Current high-efficacy disease modifying therapy, such as ocrelizumab, are extraordinarily successful at preventing focal inflammation and relapses but are less effective for preventing the slow march of disability progression characterizing PIRA.^12,13 The prevention of PIRA is therefore an unmet treatment need.

Chronic active lesions (CALs) are an important driver of PIRA. When an acute gadolinium-enhancing lesion develops in PwMS, there are 3 possible fates of this lesion. The lesion may become chronically inactive, remyelinate, or transition to CALs.¹⁴ The histopathologic signature of CALs is compartmentalized, low-grade inflammation behind an intact blood-brain barrier with evidence of both active and chronic components.¹⁵ CALs may be found not only in cerebral white matter but also in the cerebral cortex and spinal cord.^16,17 Combined MRI and histopathological studies have shown that iron-laden microglia/macrophages can be detected by susceptibility-based MRI as a rim of paramagnetic signal surrounding select T2-lesions.¹⁹ These PRLs represent an in vivo imaging biomarker of CAL (Figure 1C). According to the North American Imaging in MS Cooperative (NAIMS) consensus criteria, a PRL must surround at least two-thirds of the outer edge of a T2-lesion, be visible in ≥ 2 consecutive MRI slices, and cannot be contrast enhancing.²⁰

PRLs can be visualized on multiple susceptibility-based imaging methods, including multiecho derived R2*/T2*, phase maps, susceptibility-weighted imaging, and quantitative susceptibility mapping.^21-23 Retrospective analyses have shown no significant differences in sensitivity across these imaging modalities.²⁴ Although first visualized with 7T MRI, PRLs may also be detected by 1.5T and 3T MRI with comparable sensitivities.^25-27 However, there remains a significant knowledge gap regarding the accuracy of each imaging modality. Systematic, prospectively designed studies are needed to ascertain the comparative value of each method.

The presence of PRL is a poor prognostic indicator. PwMS without PRLs have higher levels of disability, are more likely to progress, and demonstrate greater gray matter atrophy and cognitive dysfunction when compared with PwMS with PRLs.^27-29 Lesions with PRL tend to slowly expand, exhibit greater demyelination, and have diminished white matter integrity.^21,22,30

PRLs may also be used as a diagnostic tool. PRLs are highly specific for MS/CIS with a 99.7% specificity and 98.4% positive predictive value, although the sensitivity is limited to 24%.³¹ Taken together, these data indicate that the presence of a PRL substantially increases the likelihood of an MS/CIS diagnosis, whereas the absence of a PRL does not exclude these diagnoses. 

Several unanswered questions remain: Why do select acute MS lesions transition to CALs? How may investigators utilize PRLs as outcome measures in future clinical trials? How should PRLs be incorporated into the routine care of PwMS? As the role of this imaging biomarker is clarified both in the research and clinical settings, clinicians caring for PwMS can expect to increasingly encounter the topic of PRLs in the near future.

Central Vein Sign

A CVS is defined by the presence of a central vessel within a demyelinating plaque (Figure 1D). As early as the 1820s, MS plaques on gross pathology were noted to follow the course of a vessel. Early histological studies reported that up to 91% of MS plaques had a central vessel present.³² Lesion formation is dependent on the movement of lymphocytes and other inflammatory cells from the systemic circulation across the blood brain barrier into the perivascular space, a privileged site where immune cells interact with antigen presenting cells to launch an inflammatory cascade and eventual demyelinating lesion.³³

CVS can be visualized on 1.5T, 3T and 7T MRI. However, 7T MRI is superior to 3T in the detection of CVS, with 85% of MS lesions having CVS visible compared with 45% on 3T.³⁴ With advances in 7T MRI, fluid attenuated inversion recovery and T2* susceptibility, weighted sequences can be overlaid, allowing simultaneous visualization of the vessel and the demyelinating lesion. With higher density of parenchymal veins in the periventricular regions, the CVS is most seen in lesions of this territory but can also be present in juxtacortical, thalamic and infratentorial lesions with decreasing prevalence as these approach the cortex.³⁵

MS lesions are more likely to have CVS than T2 hyperintense white matter lesions of other causes, with a large study reporting 78% of MS lesions were CVS positive. Further, CVS positive lesions can be found across all MS phenotypes including relapsing remitting, primary progressive, and secondary progressive.³⁵ The CVS is also specific to MS lesions and is an effective tool for differentiating MS lesions from other common causes of T2 hyperintense lesions including chronic ischemic white matter disease,³⁶ migraines,³⁷ neuromyelitis optica spectrum disorders,^38,39 Susac syndrome,⁴⁰ and systemic autoimmune diseases (Behcet disease, systemic lupus erythematosus, and antiphospholipid syndrome).⁴¹

With CVS emerging as a promising radiographic biomarker for MS, NAIMS issued a consensus statement on necessary properties of a CVS. These criteria included appearance of a thin hypointense line or small dot, visualized in ≥ 2 perpendicular planes, with diameter < 2 mm, and running partially or entirely through the center of the lesion. They also clarified that lesions < 3 mm, confluent lesions, lesions with multiple vessels present or poorly visualized lesions were excluded.⁴²

A shared CVS definition was a necessary step toward routine use of CVS as a radiographic biomarker and its incorporation in the 2024 revised McDonald criteria.⁴³ Remaining limitations including 7T MRI is primarily available in research settings and the lack of consensus on a diagnostic threshold. There have been many proposed methods, including a 40% cut off,⁴⁴ 60% cut off,⁴⁵ and Select 3* or Select 6* methods.⁴⁶ The goal of each method is to optimize sensitivity and specificity while not compromising efficiency of MRI review for both neurologists and radiologists.

The CVS has significant potential as a radiographic biomarker for MS and may allow the early stages of MS to be differentiated from other common causes of white matter lesions on MRI. However, it remains unclear whether CVS holds prognostic value for patients, if CVS is suggestive of differing underlying pathology, or if the presence of a CVS is dynamic over time. Progress in these areas is anticipated as CVS is incorporated into routine clinical practice.

Quantitative MRI Techniques

In the research setting, several imaging modalities can be used to quantify the degree of microstructural injury in PwMS. The goal of these methods is to identify and quantify myelin and axonal damage, the major drivers of neurodegeneration. Among these methods, diffusion-based imaging is a measure of the amount of diffusion or fluid mobility across the tissues of the brain.⁴⁷ Diffusion-weighted imaging (DWI) yields several parametric maps including axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (Figure 2 A, B, and C). These parametric maps provide information on different directions of water molecules’ movements. Myelin surrounds the axons preventing water molecules diffusion perpendicular to axons (RD) while axonal content prevents water diffusion horizontal to the axons (AD).Thus, AD is considered more specific to axonal injury, whereas RD is specific to myelin content.⁴⁸ A higher value of any of these metrics is associated with a higher degree of tissue injury.

Although sensitive to axonal and myelin injury, AD and RD computed from single b-shell DWI experience several limitations including being affected by nonpathologic factors such as fiber orientation, distribution, and crossing, and by various nonmyelin specific pathologies including fluid accumulation during inflammation, myelin sheath thickness, and axonal intactness.⁴⁸ Several multi b-shell methods have been developed to overcome diffusion imaging limitations. For example, work at the Nashville VA MS Center of Excellence has focused on the use of the multicompartment diffusion MRI with spherical mean technique (SMT). This method removes the orientation dependency of the diffusion MRI signal, increasing the signal-to-noise ratio and reducing biases from fiber undulation, crossing, and dispersion.⁴⁹ SMT generates the apparent axonal volume fraction (V_ax), which is a direct measure of axonal integrity with lower values indicating lower axonal content and higher tissue destruction (Figure 2D). V_ax was previously validated in MS as a measure of axonal integrity.⁴⁹

In terms of myelin, several other specific measures have been developed. Magnetization transfer ratio (MTR) is another measure of tissue integrity that has been validated as a measure of tissue injury in MS (Figure 2E).^50,51 Zheng et al found that the percentage of lesions with low MTR was significantly higher among patients whose disease disability progressed compared with patients who did not.⁵²Selective inversion recovery with quantitative magnetization transfer (SIR-qMT) was developed to account for the limitations of MTR, including its sensitivity to edema and axonal density.⁵² Germane to myelin measurements, SIR-qMT generates the macromolecular to free size ratio (PSR). PSR represents the ratio of protons bound to macromolecules (myelin) to free protons (Figure 2F). PSR is considered a marker of myelin integrity, with lower values correlating with disability severity and indicating higher tissue damage and lower myelin content. Previous studies from the Nashville VA MS Center of Excellence validated the use of SIR-qMT among patients with MS, CIS, RIS, and healthy controls.⁵³

Quantitative MRI has several research applications in the field of MS. We demonstrated that PRL harbor a higher degree of myelin injury indicated by PSR compared with rimless lesions.⁵⁴ These MRI techniques are also helpful to investigate tissues surrounding the lesions, called normal appearing white matter (NAWM). Using quantitative MRI techniques such as MTR,⁵² PSR,⁵³ and V_ax,⁴⁹ investigators have demonstrated that NAWM is injured in PwMS, and proximal NAWM may have higher degree of tissue damage compared with distant NAWM.⁵⁵

Anticipated Innovations and Challenges

In the field of quantitative MRI, several new techniques are being adopted. Researchers are developing techniques such as myelin water fraction which evaluates the interaction between water and protons to measure myelin content. This is considered an advancement as it takes into account edema resulting from MS injury.⁵⁶ Another example is multicompartment diffusion imaging, such as standard model imaging,⁵⁷ and neurite orientation dispersion and density imaging,⁵⁸ which considers water as an additional compartment compared with the SMT derived V_ax. For PRL identification, more advanced methodologic techniques are developing such quantitative susceptibility mapping (QSM), which can detect iron deposits that surround the lesions with relatively high sensitivity and specificity of identifying PRL.⁵⁹

Despite these innovations, several challenges remain before possible incorporation into the clinical setting. These limitations include longer scan time, familiarity of clinicians in using these maps, higher financial cost, and the necessity of advanced imaging processing skills. Artificial intelligence is a promising tool that may overcome these challenges through creating automated processing pipelines and developing synthetic maps without the need for additional acquisition.⁶⁰

Conclusions

MRI is the most important tool for diagnosing and treating PwMS. Imaging biomarkers such as T2-lesions, cBHs, brain atrophy, PRLs, and CVS provide insight into the disease’s pathogenesis and are invaluable for the accurate diagnosis and prognostication of MS. Quantitative MRI techniques, while not available in the clinical setting, are important tools for translational research that may help direct the development of future therapeutics. In the near future, clinicians caring for PwMS should expect to encounter these imaging biomarkers more frequently in the clinical setting, especially with the inclusion of PRLs and CVS in the next iteration of the McDonald diagnostic criteria.

Multiple sclerosis (MS) is a complex, chronic immune-mediated disease of the central nervous system characterized by focal inflammation, demyelination, and neurodegeneration. Magnetic resonance imaging (MRI), first incorporated into the McDonald Criteria for the diagnosis of MS in 2001, is an integral tool in the diagnosis, prognosis, and therapeutic monitoring of people with MS (PwMS).¹

MRI research in MS is rapidly expanding and offers insights into the pathophysiology of MS with important implications for the routine clinical care of PwMS. At the Consortium of Multiple Sclerosis Centers 2024 Annual Meeting, the US Department of Veterans Affairs (VA) MS Centers of Excellence hosted an educational symposium highlighting MRI biomarkers in MS, including T2-lesions, chronic black holes (cBHs), brain atrophy, paramagnetic rim lesions (PRLs), and the central vein sign (CVS). The symposium also provided a brief overview of quantitative MRI techniques used to characterize MS lesion severity and research applications of these techniques. This clinical review summarizes the main points of that symposium with the goal of introducing key concepts to federal health care practitioners caring for PwMS.

MRI Biomarkers in MS

T2-lesions, Chronic Black Holes, and Brain Atrophy

Focal immune-mediated inflammation and demyelination in MS may be detected by MRI as hyperintense foci on T2-weighted (T2-w) imaging (eg, T2-w turbo spin echo or T2-w fluid attenuated inversion recovery sequences). These T2-lesions, critical for diagnosing MS, are typically ovoid and occur in the periventricular, juxtacortical, infratentorial spinal cord white matter (Figure 1A). T2-lesion number and volume show some association with disability and optic nerve.

Wattjes et al highlight 2 cases to demonstrate this point: a man aged 52 years with MS for 23 years and a woman aged 50 years with MS for 11 years. Despite having MS for a much shorter duration, the woman had worse disability due to a higher lesion number and volume.² T2-lesion volume also impacts disability progression in PwMS. Gauthier et al compared the probability of progression in 3 women, all of whom were aged 39 years and had MS for 6 years. The profile with highest probability of disability progression had the highest quartile of T2-lesion volume.³ T2-lesion volume over 2 years correlates with worse scores on disability metrics such as the MS functional composite, paced auditory serial addition task, and brain volume.⁴ A 2024 systematic review and meta-analysis demonstrated that T2-lesion volume is significantly correlated with clinical disability in PwMS.⁵

 

Select T2-lesions are also hypointense on T1-w spin echo images and are known as cBHs (Figure 1B). Histologically, T2-lesions with cBHs have more severe architectural disruption than those without cBHs.⁶ cBH number and volume are significantly correlated with disability, regardless of the degree of hypointensity on T1-w imaging.^5,7 A 10-year longitudinal study demonstrated that cBHs were associated with disease progression after 5 years while T2-lesion volume was not, indicating that cBHs may be a more accurate predictor of disability.⁸

Brain atrophy, another imaging biomarker of MS, affects both the cerebral white and gray matter. White matter fraction (the volume of white matter relative to the intracranial compartment volume) and gray matter fraction (the volume of gray matter relative to the intracranial compartment) are significantly lower among PwMS compared with healthy controls. In addition, gray matter fraction is lower among patients with primary and secondary progressive MS compared with those with relapsing-remitting MS, clinically isolated syndrome (CIS), and radiologically isolated syndrome (RIS). Gray matter fraction is also correlated with several motor and cognitive disability indices.⁹

Paramagnetic Rim Lesions

Neurologic worsening in PwMS occurs by 2 distinct mechanisms: relapse-associated worsening, a stepwise worsening of symptoms due to incomplete recovery following a relapse; and progression independent of relapse activity (PIRA), which is an irreversible neurologic deterioration in the absence of clinical or radiological relapses.¹⁰ PIRA is associated with neurodegeneration and predominates in both primary and secondary progressive MS. However, recent data demonstrated that PIRA may contribute to as much as 50% of disability worsening in relapsing MS and occurs early in the RMS disease course.^10,11 Current high-efficacy disease modifying therapy, such as ocrelizumab, are extraordinarily successful at preventing focal inflammation and relapses but are less effective for preventing the slow march of disability progression characterizing PIRA.^12,13 The prevention of PIRA is therefore an unmet treatment need.

Chronic active lesions (CALs) are an important driver of PIRA. When an acute gadolinium-enhancing lesion develops in PwMS, there are 3 possible fates of this lesion. The lesion may become chronically inactive, remyelinate, or transition to CALs.¹⁴ The histopathologic signature of CALs is compartmentalized, low-grade inflammation behind an intact blood-brain barrier with evidence of both active and chronic components.¹⁵ CALs may be found not only in cerebral white matter but also in the cerebral cortex and spinal cord.^16,17 Combined MRI and histopathological studies have shown that iron-laden microglia/macrophages can be detected by susceptibility-based MRI as a rim of paramagnetic signal surrounding select T2-lesions.¹⁹ These PRLs represent an in vivo imaging biomarker of CAL (Figure 1C). According to the North American Imaging in MS Cooperative (NAIMS) consensus criteria, a PRL must surround at least two-thirds of the outer edge of a T2-lesion, be visible in ≥ 2 consecutive MRI slices, and cannot be contrast enhancing.²⁰

PRLs can be visualized on multiple susceptibility-based imaging methods, including multiecho derived R2*/T2*, phase maps, susceptibility-weighted imaging, and quantitative susceptibility mapping.^21-23 Retrospective analyses have shown no significant differences in sensitivity across these imaging modalities.²⁴ Although first visualized with 7T MRI, PRLs may also be detected by 1.5T and 3T MRI with comparable sensitivities.^25-27 However, there remains a significant knowledge gap regarding the accuracy of each imaging modality. Systematic, prospectively designed studies are needed to ascertain the comparative value of each method.

The presence of PRL is a poor prognostic indicator. PwMS without PRLs have higher levels of disability, are more likely to progress, and demonstrate greater gray matter atrophy and cognitive dysfunction when compared with PwMS with PRLs.^27-29 Lesions with PRL tend to slowly expand, exhibit greater demyelination, and have diminished white matter integrity.^21,22,30

PRLs may also be used as a diagnostic tool. PRLs are highly specific for MS/CIS with a 99.7% specificity and 98.4% positive predictive value, although the sensitivity is limited to 24%.³¹ Taken together, these data indicate that the presence of a PRL substantially increases the likelihood of an MS/CIS diagnosis, whereas the absence of a PRL does not exclude these diagnoses. 

Several unanswered questions remain: Why do select acute MS lesions transition to CALs? How may investigators utilize PRLs as outcome measures in future clinical trials? How should PRLs be incorporated into the routine care of PwMS? As the role of this imaging biomarker is clarified both in the research and clinical settings, clinicians caring for PwMS can expect to increasingly encounter the topic of PRLs in the near future.

Central Vein Sign

A CVS is defined by the presence of a central vessel within a demyelinating plaque (Figure 1D). As early as the 1820s, MS plaques on gross pathology were noted to follow the course of a vessel. Early histological studies reported that up to 91% of MS plaques had a central vessel present.³² Lesion formation is dependent on the movement of lymphocytes and other inflammatory cells from the systemic circulation across the blood brain barrier into the perivascular space, a privileged site where immune cells interact with antigen presenting cells to launch an inflammatory cascade and eventual demyelinating lesion.³³

CVS can be visualized on 1.5T, 3T and 7T MRI. However, 7T MRI is superior to 3T in the detection of CVS, with 85% of MS lesions having CVS visible compared with 45% on 3T.³⁴ With advances in 7T MRI, fluid attenuated inversion recovery and T2* susceptibility, weighted sequences can be overlaid, allowing simultaneous visualization of the vessel and the demyelinating lesion. With higher density of parenchymal veins in the periventricular regions, the CVS is most seen in lesions of this territory but can also be present in juxtacortical, thalamic and infratentorial lesions with decreasing prevalence as these approach the cortex.³⁵

MS lesions are more likely to have CVS than T2 hyperintense white matter lesions of other causes, with a large study reporting 78% of MS lesions were CVS positive. Further, CVS positive lesions can be found across all MS phenotypes including relapsing remitting, primary progressive, and secondary progressive.³⁵ The CVS is also specific to MS lesions and is an effective tool for differentiating MS lesions from other common causes of T2 hyperintense lesions including chronic ischemic white matter disease,³⁶ migraines,³⁷ neuromyelitis optica spectrum disorders,^38,39 Susac syndrome,⁴⁰ and systemic autoimmune diseases (Behcet disease, systemic lupus erythematosus, and antiphospholipid syndrome).⁴¹

With CVS emerging as a promising radiographic biomarker for MS, NAIMS issued a consensus statement on necessary properties of a CVS. These criteria included appearance of a thin hypointense line or small dot, visualized in ≥ 2 perpendicular planes, with diameter < 2 mm, and running partially or entirely through the center of the lesion. They also clarified that lesions < 3 mm, confluent lesions, lesions with multiple vessels present or poorly visualized lesions were excluded.⁴²

A shared CVS definition was a necessary step toward routine use of CVS as a radiographic biomarker and its incorporation in the 2024 revised McDonald criteria.⁴³ Remaining limitations including 7T MRI is primarily available in research settings and the lack of consensus on a diagnostic threshold. There have been many proposed methods, including a 40% cut off,⁴⁴ 60% cut off,⁴⁵ and Select 3* or Select 6* methods.⁴⁶ The goal of each method is to optimize sensitivity and specificity while not compromising efficiency of MRI review for both neurologists and radiologists.

The CVS has significant potential as a radiographic biomarker for MS and may allow the early stages of MS to be differentiated from other common causes of white matter lesions on MRI. However, it remains unclear whether CVS holds prognostic value for patients, if CVS is suggestive of differing underlying pathology, or if the presence of a CVS is dynamic over time. Progress in these areas is anticipated as CVS is incorporated into routine clinical practice.

Quantitative MRI Techniques

In the research setting, several imaging modalities can be used to quantify the degree of microstructural injury in PwMS. The goal of these methods is to identify and quantify myelin and axonal damage, the major drivers of neurodegeneration. Among these methods, diffusion-based imaging is a measure of the amount of diffusion or fluid mobility across the tissues of the brain.⁴⁷ Diffusion-weighted imaging (DWI) yields several parametric maps including axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (Figure 2 A, B, and C). These parametric maps provide information on different directions of water molecules’ movements. Myelin surrounds the axons preventing water molecules diffusion perpendicular to axons (RD) while axonal content prevents water diffusion horizontal to the axons (AD).Thus, AD is considered more specific to axonal injury, whereas RD is specific to myelin content.⁴⁸ A higher value of any of these metrics is associated with a higher degree of tissue injury.

Although sensitive to axonal and myelin injury, AD and RD computed from single b-shell DWI experience several limitations including being affected by nonpathologic factors such as fiber orientation, distribution, and crossing, and by various nonmyelin specific pathologies including fluid accumulation during inflammation, myelin sheath thickness, and axonal intactness.⁴⁸ Several multi b-shell methods have been developed to overcome diffusion imaging limitations. For example, work at the Nashville VA MS Center of Excellence has focused on the use of the multicompartment diffusion MRI with spherical mean technique (SMT). This method removes the orientation dependency of the diffusion MRI signal, increasing the signal-to-noise ratio and reducing biases from fiber undulation, crossing, and dispersion.⁴⁹ SMT generates the apparent axonal volume fraction (V_ax), which is a direct measure of axonal integrity with lower values indicating lower axonal content and higher tissue destruction (Figure 2D). V_ax was previously validated in MS as a measure of axonal integrity.⁴⁹

In terms of myelin, several other specific measures have been developed. Magnetization transfer ratio (MTR) is another measure of tissue integrity that has been validated as a measure of tissue injury in MS (Figure 2E).^50,51 Zheng et al found that the percentage of lesions with low MTR was significantly higher among patients whose disease disability progressed compared with patients who did not.⁵²Selective inversion recovery with quantitative magnetization transfer (SIR-qMT) was developed to account for the limitations of MTR, including its sensitivity to edema and axonal density.⁵² Germane to myelin measurements, SIR-qMT generates the macromolecular to free size ratio (PSR). PSR represents the ratio of protons bound to macromolecules (myelin) to free protons (Figure 2F). PSR is considered a marker of myelin integrity, with lower values correlating with disability severity and indicating higher tissue damage and lower myelin content. Previous studies from the Nashville VA MS Center of Excellence validated the use of SIR-qMT among patients with MS, CIS, RIS, and healthy controls.⁵³

Quantitative MRI has several research applications in the field of MS. We demonstrated that PRL harbor a higher degree of myelin injury indicated by PSR compared with rimless lesions.⁵⁴ These MRI techniques are also helpful to investigate tissues surrounding the lesions, called normal appearing white matter (NAWM). Using quantitative MRI techniques such as MTR,⁵² PSR,⁵³ and V_ax,⁴⁹ investigators have demonstrated that NAWM is injured in PwMS, and proximal NAWM may have higher degree of tissue damage compared with distant NAWM.⁵⁵

Anticipated Innovations and Challenges

In the field of quantitative MRI, several new techniques are being adopted. Researchers are developing techniques such as myelin water fraction which evaluates the interaction between water and protons to measure myelin content. This is considered an advancement as it takes into account edema resulting from MS injury.⁵⁶ Another example is multicompartment diffusion imaging, such as standard model imaging,⁵⁷ and neurite orientation dispersion and density imaging,⁵⁸ which considers water as an additional compartment compared with the SMT derived V_ax. For PRL identification, more advanced methodologic techniques are developing such quantitative susceptibility mapping (QSM), which can detect iron deposits that surround the lesions with relatively high sensitivity and specificity of identifying PRL.⁵⁹

Despite these innovations, several challenges remain before possible incorporation into the clinical setting. These limitations include longer scan time, familiarity of clinicians in using these maps, higher financial cost, and the necessity of advanced imaging processing skills. Artificial intelligence is a promising tool that may overcome these challenges through creating automated processing pipelines and developing synthetic maps without the need for additional acquisition.⁶⁰

Conclusions

MRI is the most important tool for diagnosing and treating PwMS. Imaging biomarkers such as T2-lesions, cBHs, brain atrophy, PRLs, and CVS provide insight into the disease’s pathogenesis and are invaluable for the accurate diagnosis and prognostication of MS. Quantitative MRI techniques, while not available in the clinical setting, are important tools for translational research that may help direct the development of future therapeutics. In the near future, clinicians caring for PwMS should expect to encounter these imaging biomarkers more frequently in the clinical setting, especially with the inclusion of PRLs and CVS in the next iteration of the McDonald diagnostic criteria.

Multiple sclerosis (MS) is a complex, chronic immune-mediated disease of the central nervous system characterized by focal inflammation, demyelination, and neurodegeneration. Magnetic resonance imaging (MRI), first incorporated into the McDonald Criteria for the diagnosis of MS in 2001, is an integral tool in the diagnosis, prognosis, and therapeutic monitoring of people with MS (PwMS).¹

MRI research in MS is rapidly expanding and offers insights into the pathophysiology of MS with important implications for the routine clinical care of PwMS. At the Consortium of Multiple Sclerosis Centers 2024 Annual Meeting, the US Department of Veterans Affairs (VA) MS Centers of Excellence hosted an educational symposium highlighting MRI biomarkers in MS, including T2-lesions, chronic black holes (cBHs), brain atrophy, paramagnetic rim lesions (PRLs), and the central vein sign (CVS). The symposium also provided a brief overview of quantitative MRI techniques used to characterize MS lesion severity and research applications of these techniques. This clinical review summarizes the main points of that symposium with the goal of introducing key concepts to federal health care practitioners caring for PwMS.

MRI Biomarkers in MS

T2-lesions, Chronic Black Holes, and Brain Atrophy

Focal immune-mediated inflammation and demyelination in MS may be detected by MRI as hyperintense foci on T2-weighted (T2-w) imaging (eg, T2-w turbo spin echo or T2-w fluid attenuated inversion recovery sequences). These T2-lesions, critical for diagnosing MS, are typically ovoid and occur in the periventricular, juxtacortical, infratentorial spinal cord white matter (Figure 1A). T2-lesion number and volume show some association with disability and optic nerve.

Wattjes et al highlight 2 cases to demonstrate this point: a man aged 52 years with MS for 23 years and a woman aged 50 years with MS for 11 years. Despite having MS for a much shorter duration, the woman had worse disability due to a higher lesion number and volume.² T2-lesion volume also impacts disability progression in PwMS. Gauthier et al compared the probability of progression in 3 women, all of whom were aged 39 years and had MS for 6 years. The profile with highest probability of disability progression had the highest quartile of T2-lesion volume.³ T2-lesion volume over 2 years correlates with worse scores on disability metrics such as the MS functional composite, paced auditory serial addition task, and brain volume.⁴ A 2024 systematic review and meta-analysis demonstrated that T2-lesion volume is significantly correlated with clinical disability in PwMS.⁵

 

Select T2-lesions are also hypointense on T1-w spin echo images and are known as cBHs (Figure 1B). Histologically, T2-lesions with cBHs have more severe architectural disruption than those without cBHs.⁶ cBH number and volume are significantly correlated with disability, regardless of the degree of hypointensity on T1-w imaging.^5,7 A 10-year longitudinal study demonstrated that cBHs were associated with disease progression after 5 years while T2-lesion volume was not, indicating that cBHs may be a more accurate predictor of disability.⁸

Brain atrophy, another imaging biomarker of MS, affects both the cerebral white and gray matter. White matter fraction (the volume of white matter relative to the intracranial compartment volume) and gray matter fraction (the volume of gray matter relative to the intracranial compartment) are significantly lower among PwMS compared with healthy controls. In addition, gray matter fraction is lower among patients with primary and secondary progressive MS compared with those with relapsing-remitting MS, clinically isolated syndrome (CIS), and radiologically isolated syndrome (RIS). Gray matter fraction is also correlated with several motor and cognitive disability indices.⁹

Paramagnetic Rim Lesions

Neurologic worsening in PwMS occurs by 2 distinct mechanisms: relapse-associated worsening, a stepwise worsening of symptoms due to incomplete recovery following a relapse; and progression independent of relapse activity (PIRA), which is an irreversible neurologic deterioration in the absence of clinical or radiological relapses.¹⁰ PIRA is associated with neurodegeneration and predominates in both primary and secondary progressive MS. However, recent data demonstrated that PIRA may contribute to as much as 50% of disability worsening in relapsing MS and occurs early in the RMS disease course.^10,11 Current high-efficacy disease modifying therapy, such as ocrelizumab, are extraordinarily successful at preventing focal inflammation and relapses but are less effective for preventing the slow march of disability progression characterizing PIRA.^12,13 The prevention of PIRA is therefore an unmet treatment need.

Chronic active lesions (CALs) are an important driver of PIRA. When an acute gadolinium-enhancing lesion develops in PwMS, there are 3 possible fates of this lesion. The lesion may become chronically inactive, remyelinate, or transition to CALs.¹⁴ The histopathologic signature of CALs is compartmentalized, low-grade inflammation behind an intact blood-brain barrier with evidence of both active and chronic components.¹⁵ CALs may be found not only in cerebral white matter but also in the cerebral cortex and spinal cord.^16,17 Combined MRI and histopathological studies have shown that iron-laden microglia/macrophages can be detected by susceptibility-based MRI as a rim of paramagnetic signal surrounding select T2-lesions.¹⁹ These PRLs represent an in vivo imaging biomarker of CAL (Figure 1C). According to the North American Imaging in MS Cooperative (NAIMS) consensus criteria, a PRL must surround at least two-thirds of the outer edge of a T2-lesion, be visible in ≥ 2 consecutive MRI slices, and cannot be contrast enhancing.²⁰

PRLs can be visualized on multiple susceptibility-based imaging methods, including multiecho derived R2*/T2*, phase maps, susceptibility-weighted imaging, and quantitative susceptibility mapping.^21-23 Retrospective analyses have shown no significant differences in sensitivity across these imaging modalities.²⁴ Although first visualized with 7T MRI, PRLs may also be detected by 1.5T and 3T MRI with comparable sensitivities.^25-27 However, there remains a significant knowledge gap regarding the accuracy of each imaging modality. Systematic, prospectively designed studies are needed to ascertain the comparative value of each method.

The presence of PRL is a poor prognostic indicator. PwMS without PRLs have higher levels of disability, are more likely to progress, and demonstrate greater gray matter atrophy and cognitive dysfunction when compared with PwMS with PRLs.^27-29 Lesions with PRL tend to slowly expand, exhibit greater demyelination, and have diminished white matter integrity.^21,22,30

PRLs may also be used as a diagnostic tool. PRLs are highly specific for MS/CIS with a 99.7% specificity and 98.4% positive predictive value, although the sensitivity is limited to 24%.³¹ Taken together, these data indicate that the presence of a PRL substantially increases the likelihood of an MS/CIS diagnosis, whereas the absence of a PRL does not exclude these diagnoses. 

Several unanswered questions remain: Why do select acute MS lesions transition to CALs? How may investigators utilize PRLs as outcome measures in future clinical trials? How should PRLs be incorporated into the routine care of PwMS? As the role of this imaging biomarker is clarified both in the research and clinical settings, clinicians caring for PwMS can expect to increasingly encounter the topic of PRLs in the near future.

Central Vein Sign

A CVS is defined by the presence of a central vessel within a demyelinating plaque (Figure 1D). As early as the 1820s, MS plaques on gross pathology were noted to follow the course of a vessel. Early histological studies reported that up to 91% of MS plaques had a central vessel present.³² Lesion formation is dependent on the movement of lymphocytes and other inflammatory cells from the systemic circulation across the blood brain barrier into the perivascular space, a privileged site where immune cells interact with antigen presenting cells to launch an inflammatory cascade and eventual demyelinating lesion.³³

CVS can be visualized on 1.5T, 3T and 7T MRI. However, 7T MRI is superior to 3T in the detection of CVS, with 85% of MS lesions having CVS visible compared with 45% on 3T.³⁴ With advances in 7T MRI, fluid attenuated inversion recovery and T2* susceptibility, weighted sequences can be overlaid, allowing simultaneous visualization of the vessel and the demyelinating lesion. With higher density of parenchymal veins in the periventricular regions, the CVS is most seen in lesions of this territory but can also be present in juxtacortical, thalamic and infratentorial lesions with decreasing prevalence as these approach the cortex.³⁵

MS lesions are more likely to have CVS than T2 hyperintense white matter lesions of other causes, with a large study reporting 78% of MS lesions were CVS positive. Further, CVS positive lesions can be found across all MS phenotypes including relapsing remitting, primary progressive, and secondary progressive.³⁵ The CVS is also specific to MS lesions and is an effective tool for differentiating MS lesions from other common causes of T2 hyperintense lesions including chronic ischemic white matter disease,³⁶ migraines,³⁷ neuromyelitis optica spectrum disorders,^38,39 Susac syndrome,⁴⁰ and systemic autoimmune diseases (Behcet disease, systemic lupus erythematosus, and antiphospholipid syndrome).⁴¹

With CVS emerging as a promising radiographic biomarker for MS, NAIMS issued a consensus statement on necessary properties of a CVS. These criteria included appearance of a thin hypointense line or small dot, visualized in ≥ 2 perpendicular planes, with diameter < 2 mm, and running partially or entirely through the center of the lesion. They also clarified that lesions < 3 mm, confluent lesions, lesions with multiple vessels present or poorly visualized lesions were excluded.⁴²

A shared CVS definition was a necessary step toward routine use of CVS as a radiographic biomarker and its incorporation in the 2024 revised McDonald criteria.⁴³ Remaining limitations including 7T MRI is primarily available in research settings and the lack of consensus on a diagnostic threshold. There have been many proposed methods, including a 40% cut off,⁴⁴ 60% cut off,⁴⁵ and Select 3* or Select 6* methods.⁴⁶ The goal of each method is to optimize sensitivity and specificity while not compromising efficiency of MRI review for both neurologists and radiologists.

The CVS has significant potential as a radiographic biomarker for MS and may allow the early stages of MS to be differentiated from other common causes of white matter lesions on MRI. However, it remains unclear whether CVS holds prognostic value for patients, if CVS is suggestive of differing underlying pathology, or if the presence of a CVS is dynamic over time. Progress in these areas is anticipated as CVS is incorporated into routine clinical practice.

Quantitative MRI Techniques

In the research setting, several imaging modalities can be used to quantify the degree of microstructural injury in PwMS. The goal of these methods is to identify and quantify myelin and axonal damage, the major drivers of neurodegeneration. Among these methods, diffusion-based imaging is a measure of the amount of diffusion or fluid mobility across the tissues of the brain.⁴⁷ Diffusion-weighted imaging (DWI) yields several parametric maps including axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (Figure 2 A, B, and C). These parametric maps provide information on different directions of water molecules’ movements. Myelin surrounds the axons preventing water molecules diffusion perpendicular to axons (RD) while axonal content prevents water diffusion horizontal to the axons (AD).Thus, AD is considered more specific to axonal injury, whereas RD is specific to myelin content.⁴⁸ A higher value of any of these metrics is associated with a higher degree of tissue injury.

Although sensitive to axonal and myelin injury, AD and RD computed from single b-shell DWI experience several limitations including being affected by nonpathologic factors such as fiber orientation, distribution, and crossing, and by various nonmyelin specific pathologies including fluid accumulation during inflammation, myelin sheath thickness, and axonal intactness.⁴⁸ Several multi b-shell methods have been developed to overcome diffusion imaging limitations. For example, work at the Nashville VA MS Center of Excellence has focused on the use of the multicompartment diffusion MRI with spherical mean technique (SMT). This method removes the orientation dependency of the diffusion MRI signal, increasing the signal-to-noise ratio and reducing biases from fiber undulation, crossing, and dispersion.⁴⁹ SMT generates the apparent axonal volume fraction (V_ax), which is a direct measure of axonal integrity with lower values indicating lower axonal content and higher tissue destruction (Figure 2D). V_ax was previously validated in MS as a measure of axonal integrity.⁴⁹

In terms of myelin, several other specific measures have been developed. Magnetization transfer ratio (MTR) is another measure of tissue integrity that has been validated as a measure of tissue injury in MS (Figure 2E).^50,51 Zheng et al found that the percentage of lesions with low MTR was significantly higher among patients whose disease disability progressed compared with patients who did not.⁵²Selective inversion recovery with quantitative magnetization transfer (SIR-qMT) was developed to account for the limitations of MTR, including its sensitivity to edema and axonal density.⁵² Germane to myelin measurements, SIR-qMT generates the macromolecular to free size ratio (PSR). PSR represents the ratio of protons bound to macromolecules (myelin) to free protons (Figure 2F). PSR is considered a marker of myelin integrity, with lower values correlating with disability severity and indicating higher tissue damage and lower myelin content. Previous studies from the Nashville VA MS Center of Excellence validated the use of SIR-qMT among patients with MS, CIS, RIS, and healthy controls.⁵³

Quantitative MRI has several research applications in the field of MS. We demonstrated that PRL harbor a higher degree of myelin injury indicated by PSR compared with rimless lesions.⁵⁴ These MRI techniques are also helpful to investigate tissues surrounding the lesions, called normal appearing white matter (NAWM). Using quantitative MRI techniques such as MTR,⁵² PSR,⁵³ and V_ax,⁴⁹ investigators have demonstrated that NAWM is injured in PwMS, and proximal NAWM may have higher degree of tissue damage compared with distant NAWM.⁵⁵

Anticipated Innovations and Challenges

In the field of quantitative MRI, several new techniques are being adopted. Researchers are developing techniques such as myelin water fraction which evaluates the interaction between water and protons to measure myelin content. This is considered an advancement as it takes into account edema resulting from MS injury.⁵⁶ Another example is multicompartment diffusion imaging, such as standard model imaging,⁵⁷ and neurite orientation dispersion and density imaging,⁵⁸ which considers water as an additional compartment compared with the SMT derived V_ax. For PRL identification, more advanced methodologic techniques are developing such quantitative susceptibility mapping (QSM), which can detect iron deposits that surround the lesions with relatively high sensitivity and specificity of identifying PRL.⁵⁹

Despite these innovations, several challenges remain before possible incorporation into the clinical setting. These limitations include longer scan time, familiarity of clinicians in using these maps, higher financial cost, and the necessity of advanced imaging processing skills. Artificial intelligence is a promising tool that may overcome these challenges through creating automated processing pipelines and developing synthetic maps without the need for additional acquisition.⁶⁰

Conclusions

MRI is the most important tool for diagnosing and treating PwMS. Imaging biomarkers such as T2-lesions, cBHs, brain atrophy, PRLs, and CVS provide insight into the disease’s pathogenesis and are invaluable for the accurate diagnosis and prognostication of MS. Quantitative MRI techniques, while not available in the clinical setting, are important tools for translational research that may help direct the development of future therapeutics. In the near future, clinicians caring for PwMS should expect to encounter these imaging biomarkers more frequently in the clinical setting, especially with the inclusion of PRLs and CVS in the next iteration of the McDonald diagnostic criteria.

Background

Immune-related adverse events (irAEs) associated with checkpoint inhibitors can involve virtually any organ system. Optic neuritis is a rare but potentially reversible toxicity, with limited reports in the literature.

Case Presentation

A 57-year-old male with Stage IV poorly-differentiated neuroendocrine carcinoma presented with progressive bilateral vision loss following a near-complete response to four cycles of atezolizumab, carboplatin, and etoposide chemotherapy, and one cycle of maintenance atezolizumab. Symptoms began in the right eye and progressed to the left over 12 days. Neurological and ophthalmological evaluations included brain and orbital MRI, autoimmune panels, and infectious workup, all of which were unrevealing. The clinical picture remained consistent with isolated, immunemediated optic neuritis.

Discussion

High-dose intravenous methylprednisolone was initiated, resulting in gradual improvement and partial visual recovery by day four. An oral prednisone taper was prescribed for continued treatment. This is the second reported case of isolated optic neuritis associated with PD-L1 inhibitor therapy and the second with negative imaging findings. The rarity of this irAE and the absence of radiographic abnormalities may delay diagnosis and treatment.

Conclusions

Checkpoint-inhibitor-induced optic neuritis should be considered in patients with visual symptoms on immunotherapy, even in the setting of negative imaging. Early recognition and corticosteroid therapy are critical in preserving visual function.

Background

Immune-related adverse events (irAEs) associated with checkpoint inhibitors can involve virtually any organ system. Optic neuritis is a rare but potentially reversible toxicity, with limited reports in the literature.

Case Presentation

A 57-year-old male with Stage IV poorly-differentiated neuroendocrine carcinoma presented with progressive bilateral vision loss following a near-complete response to four cycles of atezolizumab, carboplatin, and etoposide chemotherapy, and one cycle of maintenance atezolizumab. Symptoms began in the right eye and progressed to the left over 12 days. Neurological and ophthalmological evaluations included brain and orbital MRI, autoimmune panels, and infectious workup, all of which were unrevealing. The clinical picture remained consistent with isolated, immunemediated optic neuritis.

Discussion

High-dose intravenous methylprednisolone was initiated, resulting in gradual improvement and partial visual recovery by day four. An oral prednisone taper was prescribed for continued treatment. This is the second reported case of isolated optic neuritis associated with PD-L1 inhibitor therapy and the second with negative imaging findings. The rarity of this irAE and the absence of radiographic abnormalities may delay diagnosis and treatment.

Conclusions

Checkpoint-inhibitor-induced optic neuritis should be considered in patients with visual symptoms on immunotherapy, even in the setting of negative imaging. Early recognition and corticosteroid therapy are critical in preserving visual function.

Background

Immune-related adverse events (irAEs) associated with checkpoint inhibitors can involve virtually any organ system. Optic neuritis is a rare but potentially reversible toxicity, with limited reports in the literature.

Case Presentation

A 57-year-old male with Stage IV poorly-differentiated neuroendocrine carcinoma presented with progressive bilateral vision loss following a near-complete response to four cycles of atezolizumab, carboplatin, and etoposide chemotherapy, and one cycle of maintenance atezolizumab. Symptoms began in the right eye and progressed to the left over 12 days. Neurological and ophthalmological evaluations included brain and orbital MRI, autoimmune panels, and infectious workup, all of which were unrevealing. The clinical picture remained consistent with isolated, immunemediated optic neuritis.

Discussion

High-dose intravenous methylprednisolone was initiated, resulting in gradual improvement and partial visual recovery by day four. An oral prednisone taper was prescribed for continued treatment. This is the second reported case of isolated optic neuritis associated with PD-L1 inhibitor therapy and the second with negative imaging findings. The rarity of this irAE and the absence of radiographic abnormalities may delay diagnosis and treatment.

Conclusions

Checkpoint-inhibitor-induced optic neuritis should be considered in patients with visual symptoms on immunotherapy, even in the setting of negative imaging. Early recognition and corticosteroid therapy are critical in preserving visual function.

Click to view more from Federal Health Care Data Trends 2025.

Click to view more from Federal Health Care Data Trends 2025.

Click to view more from Federal Health Care Data Trends 2025.

Chronic cough remains a common reason for consultation in pulmonology post–COVID-19. But what do we really know about this condition, now 5 years after the pandemic’s onset? This topic was discussed at the recent French-Speaking Pneumology Congress held in Marseille, France, from January 24-26, 2025.

Before discussing post-COVID cough, it is crucial to differentiate between an acute cough, often viral in origin (including those associated with SARS-CoV-2), a subacute cough (lasting 3-8 weeks), and a chronic cough (persisting over 8 weeks).

“This distinction allows us to tailor treatment and prescribe the appropriate investigations, according to the duration and the probability of symptom resolution,” explained Laurent Guilleminault, MD, PhD, pulmonologist at Toulouse University Hospital Centre, Toulouse, France.

In the case of an acute cough, for instance, after a viral infection, the probability of spontaneous resolution is very high. It is often unnecessary to carry out additional examinations or initiate specific treatments because none has proven its effectiveness in shortening this type of cough. On the other hand, when a cough persists beyond 8 weeks, the chance of spontaneous resolution decreases considerably. “This is when an assessment is necessary to identify a possible underlying cause,” Guilleminault noted.

“The absence of coughing during the consultation should not lead to ruling out a diagnosis,” he added.

Neurological Link

A large-scale French study of 70,000 patients examined the demographic profiles of patients with COVID-19. It revealed a lower frequency of coughing among children and older individuals, with a notable prevalence among adults aged 30-60 years.

Furthermore, during the acute phase of COVID, coughing did not appear to indicate severity. A comparison between survivors and nonsurvivors revealed no significant differences in the frequency and severity of coughing. Another study concluded that, contrary to expectations, COVID-related pneumonia, although potentially severe, does not necessarily involve severe cough.

These findings highlight the absence of a direct link between coughing and pulmonary involvement in patients with COVID-19.

“Coughing appears to be more closely linked to neurological dysfunction than to classic respiratory involvement. A distinction that is essential for better understanding the pathophysiology of the disease and guiding therapeutic strategies,” Guilleminault noted.

Cough Mechanism

“The analysis of cough in the context of phylogenetic evolution is fascinating,” explained Guilleminault. “It illustrates how this reflex has provided an advantage to the virus for its propagation.” Studies on the transmission of SARS-CoV-2 have confirmed that coughing plays a key role in the spread of viral particles. However, this mechanism does not involve severe pulmonary damage. The primary goal of the virus is to induce neurological dysfunction in the host by triggering a cough reflex. This neurological activation enables the virus to trigger a cough reflex for dissemination even without significant pulmonary damage. This mechanism provides an evolutionary advantage by enhancing the ability of the virus to spread and colonize new hosts.

The cough mechanism remains partially understood and involves cough hypersensitivity, characterized by increased neural responsivity to a range of stimuli that affect the airways, lungs, and other tissues innervated by common nerve supplies. The cough reflex begins with the activation of sensitive peripheral receptors located mainly in the respiratory tract that detect irritants or abnormalities.

These receptors, such as P2X2, P2X3, and others, transmit information to the brainstem, which coordinates the reflex response. This process is modulated by cortical controls that normally inhibit spontaneous coughing, explaining why we do not cough constantly even in the presence of moderate stimuli.

However, when there is an imbalance in this inhibition mechanism, coughing can be triggered either excessively or uncontrollably. SARS-CoV-2 appears to interact directly with these peripheral receptors, stimulating the cough reflex. The widespread presence and density of these receptors make this mechanism highly effective for the virus’s transmission.

Additionally, the vagus nerve likely plays a central role in triggering cough, particularly in viral infections. Studies of influenza have shown the involvement of sensory cells associated with the vagus nerve.

The virus stimulates the vagus nerve, which activates the cough reflex. Research suggests that neurotropism, neuroinflammation, and neuroimmunomodulation via the vagal sensory nerves, which are involved in SARS-CoV-2 infection, lead to cough hypersensitivity.

One question remains: Could vagus nerve involvement prolong coughing beyond the active phase of viral infection? The data indicate that viral infection significantly increases the sensitivity of the cough reflex, regardless of the level of irritation. The brain areas involved in inhibiting this reflex appear less effective during viral infection, resulting in reduced inhibitory control and easier triggering of cough. This phenomenon reflects temporary dysfunction of the neurological modulation system, which gradually recovers after recovery.

Long-Term Effects

The epidemiology of post-COVID cough and its integration into the framework of the long COVID framework remain subjects of ongoing debate. Early studies have revealed that cough could be either an isolated symptom or associated with other manifestations of long COVID. These studies were often conducted over relatively short periods (14-110 days) and estimated that approximately 19% of patients with long COVID experienced persistent cough. Another study found that 14% of patients reported cough between 3 weeks and 3 months after hospital discharge for COVID-19.

Longer follow-up periods showed a significant decrease in the prevalence of cough over time. For instance, a 1-year study reported that only 2.5% of patients had episodes of chronic cough.

However, a 2023 study published in JAMA found that the prevalence of post-COVID chronic cough exceeded 30% in some groups of patients.

“It is not relevant to wait so long before acting,” Guilleminault said. A reasonable threshold for evaluation and treatment is 8-12 weeks postinfection to begin investigations and consider appropriate treatment. What should be done when a patient presents with “Doctor, I had COVID, I have a cough, and it hasn’t stopped?” These situations are common in clinical practice. In terms of severity, quality of life, and overall impact, patients with chronic post-COVID cough are not significantly different from those with other chronic coughs. Moreover, both conditions involve a real neurological dysfunction.

Same Diagnostic Steps

Management should follow existing guidelines, including the recent French recommendations for chronic cough.

A visual analog scale can be used, and possible complications should be assessed. A chest x-ray is recommended to identify any warning signs, such as cough, although linked to COVID — may coincide with other conditions, such as bronchial cancer. In smokers, chest CT should be considered to rule out neoplastic pathology. The presence of interstitial lesions, particularly fibrosing lesions, suggests that fibrosing interstitial pneumonia requires specialized management.

Smoking, which is an aggravating factor, should be discontinued. Discontinuing angiotensin-converting enzyme inhibitors for 4 weeks can help determine if they contribute to cough.

The three most common causes of chronic cough — rhinosinusitis, asthma, and gastroesophageal reflux disease — should be ruled out. Diagnosis is based on history, physical examination, and specific tests: Nasofibroscopy for rhinosinusitis, spirometry, fractional exhaled nitric oxide for asthma and clinical history of gastroesophageal reflux disease. Studies have indicated that asthma may develop after a COVID infection.

Laryngeal abnormalities are also common in chronic post-COVID cough. One study found that a quarter of patients had increased laryngeal sensitivity or voice changes. “The larynx, a highly cough-producing organ, causes more coughing than the lungs,” Guilleminault explained.

Laryngeal abnormalities are frequently observed. A study found that 63% of patients experienced dysphonia, 56% had a sensation of a foreign body in the larynx, and 10% experienced laryngospasms.

These issues are common in patients with post-COVID cough and are often associated with neurological dysfunction. Innervation of the larynx is complex and can be affected by viruses, leading to hypersensitivity, paresthesia, and other sensory disturbances, which may explain the laryngeal symptoms observed in these patients.

Next Steps

If common causes such as asthma, abnormal imaging findings, or laryngeal pathology are ruled out, the condition may be classified as a chronic refractory or unexplained cough. In these cases, the neurological origin is likely due to nervous system dysfunction. Neuromodulatory treatments including amitriptyline, pregabalin, and gabapentin may be considered in some cases. Corticosteroids are generally ineffective against chronic coughs.

This story was translated from Medscape’s French edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

Chronic cough remains a common reason for consultation in pulmonology post–COVID-19. But what do we really know about this condition, now 5 years after the pandemic’s onset? This topic was discussed at the recent French-Speaking Pneumology Congress held in Marseille, France, from January 24-26, 2025.

Before discussing post-COVID cough, it is crucial to differentiate between an acute cough, often viral in origin (including those associated with SARS-CoV-2), a subacute cough (lasting 3-8 weeks), and a chronic cough (persisting over 8 weeks).

“This distinction allows us to tailor treatment and prescribe the appropriate investigations, according to the duration and the probability of symptom resolution,” explained Laurent Guilleminault, MD, PhD, pulmonologist at Toulouse University Hospital Centre, Toulouse, France.

In the case of an acute cough, for instance, after a viral infection, the probability of spontaneous resolution is very high. It is often unnecessary to carry out additional examinations or initiate specific treatments because none has proven its effectiveness in shortening this type of cough. On the other hand, when a cough persists beyond 8 weeks, the chance of spontaneous resolution decreases considerably. “This is when an assessment is necessary to identify a possible underlying cause,” Guilleminault noted.

“The absence of coughing during the consultation should not lead to ruling out a diagnosis,” he added.

Neurological Link

A large-scale French study of 70,000 patients examined the demographic profiles of patients with COVID-19. It revealed a lower frequency of coughing among children and older individuals, with a notable prevalence among adults aged 30-60 years.

Furthermore, during the acute phase of COVID, coughing did not appear to indicate severity. A comparison between survivors and nonsurvivors revealed no significant differences in the frequency and severity of coughing. Another study concluded that, contrary to expectations, COVID-related pneumonia, although potentially severe, does not necessarily involve severe cough.

These findings highlight the absence of a direct link between coughing and pulmonary involvement in patients with COVID-19.

“Coughing appears to be more closely linked to neurological dysfunction than to classic respiratory involvement. A distinction that is essential for better understanding the pathophysiology of the disease and guiding therapeutic strategies,” Guilleminault noted.

Cough Mechanism

“The analysis of cough in the context of phylogenetic evolution is fascinating,” explained Guilleminault. “It illustrates how this reflex has provided an advantage to the virus for its propagation.” Studies on the transmission of SARS-CoV-2 have confirmed that coughing plays a key role in the spread of viral particles. However, this mechanism does not involve severe pulmonary damage. The primary goal of the virus is to induce neurological dysfunction in the host by triggering a cough reflex. This neurological activation enables the virus to trigger a cough reflex for dissemination even without significant pulmonary damage. This mechanism provides an evolutionary advantage by enhancing the ability of the virus to spread and colonize new hosts.

The cough mechanism remains partially understood and involves cough hypersensitivity, characterized by increased neural responsivity to a range of stimuli that affect the airways, lungs, and other tissues innervated by common nerve supplies. The cough reflex begins with the activation of sensitive peripheral receptors located mainly in the respiratory tract that detect irritants or abnormalities.

These receptors, such as P2X2, P2X3, and others, transmit information to the brainstem, which coordinates the reflex response. This process is modulated by cortical controls that normally inhibit spontaneous coughing, explaining why we do not cough constantly even in the presence of moderate stimuli.

However, when there is an imbalance in this inhibition mechanism, coughing can be triggered either excessively or uncontrollably. SARS-CoV-2 appears to interact directly with these peripheral receptors, stimulating the cough reflex. The widespread presence and density of these receptors make this mechanism highly effective for the virus’s transmission.

Additionally, the vagus nerve likely plays a central role in triggering cough, particularly in viral infections. Studies of influenza have shown the involvement of sensory cells associated with the vagus nerve.

The virus stimulates the vagus nerve, which activates the cough reflex. Research suggests that neurotropism, neuroinflammation, and neuroimmunomodulation via the vagal sensory nerves, which are involved in SARS-CoV-2 infection, lead to cough hypersensitivity.

One question remains: Could vagus nerve involvement prolong coughing beyond the active phase of viral infection? The data indicate that viral infection significantly increases the sensitivity of the cough reflex, regardless of the level of irritation. The brain areas involved in inhibiting this reflex appear less effective during viral infection, resulting in reduced inhibitory control and easier triggering of cough. This phenomenon reflects temporary dysfunction of the neurological modulation system, which gradually recovers after recovery.

Long-Term Effects

The epidemiology of post-COVID cough and its integration into the framework of the long COVID framework remain subjects of ongoing debate. Early studies have revealed that cough could be either an isolated symptom or associated with other manifestations of long COVID. These studies were often conducted over relatively short periods (14-110 days) and estimated that approximately 19% of patients with long COVID experienced persistent cough. Another study found that 14% of patients reported cough between 3 weeks and 3 months after hospital discharge for COVID-19.

Longer follow-up periods showed a significant decrease in the prevalence of cough over time. For instance, a 1-year study reported that only 2.5% of patients had episodes of chronic cough.

However, a 2023 study published in JAMA found that the prevalence of post-COVID chronic cough exceeded 30% in some groups of patients.

“It is not relevant to wait so long before acting,” Guilleminault said. A reasonable threshold for evaluation and treatment is 8-12 weeks postinfection to begin investigations and consider appropriate treatment. What should be done when a patient presents with “Doctor, I had COVID, I have a cough, and it hasn’t stopped?” These situations are common in clinical practice. In terms of severity, quality of life, and overall impact, patients with chronic post-COVID cough are not significantly different from those with other chronic coughs. Moreover, both conditions involve a real neurological dysfunction.

Same Diagnostic Steps

Management should follow existing guidelines, including the recent French recommendations for chronic cough.

A visual analog scale can be used, and possible complications should be assessed. A chest x-ray is recommended to identify any warning signs, such as cough, although linked to COVID — may coincide with other conditions, such as bronchial cancer. In smokers, chest CT should be considered to rule out neoplastic pathology. The presence of interstitial lesions, particularly fibrosing lesions, suggests that fibrosing interstitial pneumonia requires specialized management.

Smoking, which is an aggravating factor, should be discontinued. Discontinuing angiotensin-converting enzyme inhibitors for 4 weeks can help determine if they contribute to cough.

The three most common causes of chronic cough — rhinosinusitis, asthma, and gastroesophageal reflux disease — should be ruled out. Diagnosis is based on history, physical examination, and specific tests: Nasofibroscopy for rhinosinusitis, spirometry, fractional exhaled nitric oxide for asthma and clinical history of gastroesophageal reflux disease. Studies have indicated that asthma may develop after a COVID infection.

Laryngeal abnormalities are also common in chronic post-COVID cough. One study found that a quarter of patients had increased laryngeal sensitivity or voice changes. “The larynx, a highly cough-producing organ, causes more coughing than the lungs,” Guilleminault explained.

Laryngeal abnormalities are frequently observed. A study found that 63% of patients experienced dysphonia, 56% had a sensation of a foreign body in the larynx, and 10% experienced laryngospasms.

These issues are common in patients with post-COVID cough and are often associated with neurological dysfunction. Innervation of the larynx is complex and can be affected by viruses, leading to hypersensitivity, paresthesia, and other sensory disturbances, which may explain the laryngeal symptoms observed in these patients.

Next Steps

If common causes such as asthma, abnormal imaging findings, or laryngeal pathology are ruled out, the condition may be classified as a chronic refractory or unexplained cough. In these cases, the neurological origin is likely due to nervous system dysfunction. Neuromodulatory treatments including amitriptyline, pregabalin, and gabapentin may be considered in some cases. Corticosteroids are generally ineffective against chronic coughs.

This story was translated from Medscape’s French edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

Chronic cough remains a common reason for consultation in pulmonology post–COVID-19. But what do we really know about this condition, now 5 years after the pandemic’s onset? This topic was discussed at the recent French-Speaking Pneumology Congress held in Marseille, France, from January 24-26, 2025.

Before discussing post-COVID cough, it is crucial to differentiate between an acute cough, often viral in origin (including those associated with SARS-CoV-2), a subacute cough (lasting 3-8 weeks), and a chronic cough (persisting over 8 weeks).

“This distinction allows us to tailor treatment and prescribe the appropriate investigations, according to the duration and the probability of symptom resolution,” explained Laurent Guilleminault, MD, PhD, pulmonologist at Toulouse University Hospital Centre, Toulouse, France.

In the case of an acute cough, for instance, after a viral infection, the probability of spontaneous resolution is very high. It is often unnecessary to carry out additional examinations or initiate specific treatments because none has proven its effectiveness in shortening this type of cough. On the other hand, when a cough persists beyond 8 weeks, the chance of spontaneous resolution decreases considerably. “This is when an assessment is necessary to identify a possible underlying cause,” Guilleminault noted.

“The absence of coughing during the consultation should not lead to ruling out a diagnosis,” he added.

Neurological Link

A large-scale French study of 70,000 patients examined the demographic profiles of patients with COVID-19. It revealed a lower frequency of coughing among children and older individuals, with a notable prevalence among adults aged 30-60 years.

Furthermore, during the acute phase of COVID, coughing did not appear to indicate severity. A comparison between survivors and nonsurvivors revealed no significant differences in the frequency and severity of coughing. Another study concluded that, contrary to expectations, COVID-related pneumonia, although potentially severe, does not necessarily involve severe cough.

These findings highlight the absence of a direct link between coughing and pulmonary involvement in patients with COVID-19.

“Coughing appears to be more closely linked to neurological dysfunction than to classic respiratory involvement. A distinction that is essential for better understanding the pathophysiology of the disease and guiding therapeutic strategies,” Guilleminault noted.

Cough Mechanism

“The analysis of cough in the context of phylogenetic evolution is fascinating,” explained Guilleminault. “It illustrates how this reflex has provided an advantage to the virus for its propagation.” Studies on the transmission of SARS-CoV-2 have confirmed that coughing plays a key role in the spread of viral particles. However, this mechanism does not involve severe pulmonary damage. The primary goal of the virus is to induce neurological dysfunction in the host by triggering a cough reflex. This neurological activation enables the virus to trigger a cough reflex for dissemination even without significant pulmonary damage. This mechanism provides an evolutionary advantage by enhancing the ability of the virus to spread and colonize new hosts.

The cough mechanism remains partially understood and involves cough hypersensitivity, characterized by increased neural responsivity to a range of stimuli that affect the airways, lungs, and other tissues innervated by common nerve supplies. The cough reflex begins with the activation of sensitive peripheral receptors located mainly in the respiratory tract that detect irritants or abnormalities.

These receptors, such as P2X2, P2X3, and others, transmit information to the brainstem, which coordinates the reflex response. This process is modulated by cortical controls that normally inhibit spontaneous coughing, explaining why we do not cough constantly even in the presence of moderate stimuli.

However, when there is an imbalance in this inhibition mechanism, coughing can be triggered either excessively or uncontrollably. SARS-CoV-2 appears to interact directly with these peripheral receptors, stimulating the cough reflex. The widespread presence and density of these receptors make this mechanism highly effective for the virus’s transmission.

Additionally, the vagus nerve likely plays a central role in triggering cough, particularly in viral infections. Studies of influenza have shown the involvement of sensory cells associated with the vagus nerve.

The virus stimulates the vagus nerve, which activates the cough reflex. Research suggests that neurotropism, neuroinflammation, and neuroimmunomodulation via the vagal sensory nerves, which are involved in SARS-CoV-2 infection, lead to cough hypersensitivity.

One question remains: Could vagus nerve involvement prolong coughing beyond the active phase of viral infection? The data indicate that viral infection significantly increases the sensitivity of the cough reflex, regardless of the level of irritation. The brain areas involved in inhibiting this reflex appear less effective during viral infection, resulting in reduced inhibitory control and easier triggering of cough. This phenomenon reflects temporary dysfunction of the neurological modulation system, which gradually recovers after recovery.

Long-Term Effects

The epidemiology of post-COVID cough and its integration into the framework of the long COVID framework remain subjects of ongoing debate. Early studies have revealed that cough could be either an isolated symptom or associated with other manifestations of long COVID. These studies were often conducted over relatively short periods (14-110 days) and estimated that approximately 19% of patients with long COVID experienced persistent cough. Another study found that 14% of patients reported cough between 3 weeks and 3 months after hospital discharge for COVID-19.

Longer follow-up periods showed a significant decrease in the prevalence of cough over time. For instance, a 1-year study reported that only 2.5% of patients had episodes of chronic cough.

However, a 2023 study published in JAMA found that the prevalence of post-COVID chronic cough exceeded 30% in some groups of patients.

“It is not relevant to wait so long before acting,” Guilleminault said. A reasonable threshold for evaluation and treatment is 8-12 weeks postinfection to begin investigations and consider appropriate treatment. What should be done when a patient presents with “Doctor, I had COVID, I have a cough, and it hasn’t stopped?” These situations are common in clinical practice. In terms of severity, quality of life, and overall impact, patients with chronic post-COVID cough are not significantly different from those with other chronic coughs. Moreover, both conditions involve a real neurological dysfunction.

Same Diagnostic Steps

Management should follow existing guidelines, including the recent French recommendations for chronic cough.

A visual analog scale can be used, and possible complications should be assessed. A chest x-ray is recommended to identify any warning signs, such as cough, although linked to COVID — may coincide with other conditions, such as bronchial cancer. In smokers, chest CT should be considered to rule out neoplastic pathology. The presence of interstitial lesions, particularly fibrosing lesions, suggests that fibrosing interstitial pneumonia requires specialized management.

Smoking, which is an aggravating factor, should be discontinued. Discontinuing angiotensin-converting enzyme inhibitors for 4 weeks can help determine if they contribute to cough.

The three most common causes of chronic cough — rhinosinusitis, asthma, and gastroesophageal reflux disease — should be ruled out. Diagnosis is based on history, physical examination, and specific tests: Nasofibroscopy for rhinosinusitis, spirometry, fractional exhaled nitric oxide for asthma and clinical history of gastroesophageal reflux disease. Studies have indicated that asthma may develop after a COVID infection.

Laryngeal abnormalities are also common in chronic post-COVID cough. One study found that a quarter of patients had increased laryngeal sensitivity or voice changes. “The larynx, a highly cough-producing organ, causes more coughing than the lungs,” Guilleminault explained.

Laryngeal abnormalities are frequently observed. A study found that 63% of patients experienced dysphonia, 56% had a sensation of a foreign body in the larynx, and 10% experienced laryngospasms.

These issues are common in patients with post-COVID cough and are often associated with neurological dysfunction. Innervation of the larynx is complex and can be affected by viruses, leading to hypersensitivity, paresthesia, and other sensory disturbances, which may explain the laryngeal symptoms observed in these patients.

Next Steps

If common causes such as asthma, abnormal imaging findings, or laryngeal pathology are ruled out, the condition may be classified as a chronic refractory or unexplained cough. In these cases, the neurological origin is likely due to nervous system dysfunction. Neuromodulatory treatments including amitriptyline, pregabalin, and gabapentin may be considered in some cases. Corticosteroids are generally ineffective against chronic coughs.

This story was translated from Medscape’s French edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

New evidence–based clinical practice guidelines from the Alzheimer’s Association provide updated recommendations on evaluating individuals suspected of having Alzheimer’s disease and Alzheimer’s disease–related neurodegenerative disorders in both primary and specialty care settings.

This is the first update since 2001 for specialists and the first guideline for primary care physicians. Executive summaries of the guidelines were published in three articles online on December 23 in a special issue of Alzheimer’s & Dementia.

 

What’s New? 

“With this guideline, we expand the scope of prior guidelines by providing recommendations for practicing clinicians on the process from start to finish,” coauthor Brad Dickerson, MD, director of the Massachusetts General Hospital Frontotemporal Disorders Unit and professor of neurology at Harvard Medical School, Boston, said in a statement.

“If clinicians adopt these recommendations and healthcare systems provide adequate resources, outcomes should improve in most patients in most practice settings,” Dickerson added in an interview.

Through a modified-Delphi approach and guideline-development process, an expert workgroup representing primary and specialty care reviewed 7374 publications, of which 133 met inclusion criteria.

Based on the information, the workgroup outlined a three-step patient-centered evaluation process, which includes assessing cognitive functional status, identifying the cognitive-behavioral syndrome based on specific symptoms, and determining the likely brain diseases or conditions causing the symptoms.

 

What Are the Key Recommendations?

The guidelines include 19 “practical” recommendations that are applicable to any practice setting. They capture the core elements of a high-quality evaluation and disclosure process, the author said. Here is a brief summary of the recommendations: 

Initial evaluation: Perform a multitiered evaluation for patients who self-report or whose care partner or clinician reports cognitive, behavioral, or functional changes.

Patient-centered communication: Partner with the patient and/or care partner to establish shared goals for the evaluation process; assess the patient’s capacity to engage in goal setting.

Diagnostic formulation: Use a tiered approach to assessments and tests based on individual presentation, risk factors, and profile, aiming to determine the level of impairment, cognitive-behavioral syndrome, and likely causes and contributing factors.

History taking: Gather reliable information from informants about changes in cognition, activities of daily living, mood, neuropsychiatric symptoms, and sensory/motor functions. Document individualized risk factors for cognitive decline.

Examination: Conduct a comprehensive examination of cognition, mood, behavior, and a dementia-focused neurologic evaluation using validated tools.

Laboratory tests: Perform tiered, individualized laboratory evaluations, starting with routine tests for all patients.

Structural imaging: Obtain structural brain imaging (MRI preferred, CT as an alternative) to help establish a cause.

Ongoing communication: Engage in ongoing dialogue with patient/care partner to guide them throughout the diagnostic process.

Diagnostic disclosure: Share findings honestly and compassionately, explaining the syndrome, its severity, probable cause, prognosis, treatment options and support resources.

Specialist referral: Refer patients with atypical, uncertain, early-onset, or rapidly progressing symptoms to a dementia subspecialist.

Neuropsychological testing: Use in instances of diagnostic uncertainty or patients with complex clinical profiles. At a minimum, the neuropsychological evaluation should include normed neuropsychological testing of the domains of learning and memory (in particular delayed free and cued recall/recognition), attention, executive function, visuospatial function, and language.

Advanced diagnostic testing: When diagnostic uncertainty remains, obtain additional laboratory tests tailored to individual patient profiles.

Molecular imaging: In a patient with an established cognitive-behavioral syndrome in whom there is continued diagnostic uncertainty regarding cause(s) after structural imaging, a dementia specialist can obtain molecular imaging with fluorodeoxyglucose PET to improve diagnostic accuracy.

Cerebrospinal fluid (CSF) analysis: Utilize CSF biomarkers to evaluate amyloid beta and tau profiles in cases with unresolved diagnostic uncertainty.

Amyloid PET imaging: Perform amyloid PET scans for patients with persistent diagnostic uncertainty after other assessments.

Genetic counseling and testing: Consider genetic testing for patients with strong autosomal dominant family histories and involve a genetic counselor.

 

Future Directions?

Maria C. Carrillo, PhD, chief science officer and medical affairs lead for the Alzheimer’s Association, encourages clinicians to incorporate these guidelines into their practice.

“These guidelines are important because they guide clinicians in the evaluation of memory complaints, which could have many underlying causes. That is the necessary start for an early and accurate Alzheimer’s diagnosis,” Carrillo said in a statement.

Dickerson said the new guidelines do not address blood-based biomarkers “because nobody really feels that they are ready for prime time yet, even though they’re getting rolled out as clinical products.” 

However, the recommendations will be revised as needed. “That’s one of the values of setting this up as a process; whenever any new development occurs, it will be easy to update the guidelines to show where that new test or new biomarker fits in the overall process,” he said.

 

New Appropriate Use Guidance

A separate workgroup, jointly convened by the Alzheimer’s Association and the Society of Nuclear Medicine and Molecular Imaging, has revised appropriate use criteria (AUC) for amyloid PET imaging and developed AUC for tau PET imaging.

They were simultaneously published online in Alzheimer’s & Dementia and The Journal of Nuclear Medicine. They are the first revision since the initial AUC for amyloid PET was introduced in 2013.

“The updated amyloid/tau appropriate use criteria will help ensure these tracers are used in a cost-effective manner and the scan results will be used appropriately to add value to the diagnosis and management of dementia,” said workgroup members Kevin Donohoe, MD, with Beth Israel Deaconess Medical Center, Boston, and Phillip Kuo, MD, with City of Hope National Medical Center, Duarte, California.

The AUC include 17 real-world scenarios in which amyloid or tau PET may be considered, with the two tests considered separately and given their own rating for each scenario.

Overall, the strongest evidence for their use includes assessment and prognosis for people with mild cognitive impairment; assessment of people with dementia when the cause is not clearly known; and determining eligibility for treatment with new disease-modifying therapies, and monitoring response to these treatments, the workgroup said.

“Whereas the prior AUC was written at a time when only the deposition of amyloid could be documented, the new therapeutic agents allow us to demonstrate the actual clearance of amyloid during therapy,” Donohoe and Kuo explained.

“These new therapeutic agents are expensive and, as with most medications, may cause unwanted side effects. The most recent version of the AUC includes information about the appropriate use of amyloid imaging for both documenting the presence of amyloid deposits in the brain, making anti-amyloid therapy an option, as well as documenting the effectiveness of the therapeutic agents as amyloid is (or is not) cleared from the brain,” Donahoe and Kuo noted.

The revised AUC also state that, in most cases, amyloid and tau PET tests should not be used for people who do not have cognitive impairment, even if they carry the APOE4 risk-related gene for Alzheimer’s disease; nonmedical use such as for legal concerns, insurance coverage, or employment screening; and in place of genetic testing in patients suspected of carrying a disease-causing genetic mutation.

In a statement, lead author Gil D. Rabinovici, MD, with University of California, San Francisco, emphasized that the AUC “should be considered guidelines for clinicians, not a substitute for careful clinical judgment that considers the full clinical context for each patient with cognitive complaints.”

This research was funded by the Alzheimer’s Association. Disclosures for guideline authors are available with the original articles.

A version of this article first appeared on Medscape.com.

New evidence–based clinical practice guidelines from the Alzheimer’s Association provide updated recommendations on evaluating individuals suspected of having Alzheimer’s disease and Alzheimer’s disease–related neurodegenerative disorders in both primary and specialty care settings.

This is the first update since 2001 for specialists and the first guideline for primary care physicians. Executive summaries of the guidelines were published in three articles online on December 23 in a special issue of Alzheimer’s & Dementia.

 

What’s New? 

“With this guideline, we expand the scope of prior guidelines by providing recommendations for practicing clinicians on the process from start to finish,” coauthor Brad Dickerson, MD, director of the Massachusetts General Hospital Frontotemporal Disorders Unit and professor of neurology at Harvard Medical School, Boston, said in a statement.

“If clinicians adopt these recommendations and healthcare systems provide adequate resources, outcomes should improve in most patients in most practice settings,” Dickerson added in an interview.

Through a modified-Delphi approach and guideline-development process, an expert workgroup representing primary and specialty care reviewed 7374 publications, of which 133 met inclusion criteria.

Based on the information, the workgroup outlined a three-step patient-centered evaluation process, which includes assessing cognitive functional status, identifying the cognitive-behavioral syndrome based on specific symptoms, and determining the likely brain diseases or conditions causing the symptoms.

 

What Are the Key Recommendations?

The guidelines include 19 “practical” recommendations that are applicable to any practice setting. They capture the core elements of a high-quality evaluation and disclosure process, the author said. Here is a brief summary of the recommendations: 

Initial evaluation: Perform a multitiered evaluation for patients who self-report or whose care partner or clinician reports cognitive, behavioral, or functional changes.

Patient-centered communication: Partner with the patient and/or care partner to establish shared goals for the evaluation process; assess the patient’s capacity to engage in goal setting.

Diagnostic formulation: Use a tiered approach to assessments and tests based on individual presentation, risk factors, and profile, aiming to determine the level of impairment, cognitive-behavioral syndrome, and likely causes and contributing factors.

History taking: Gather reliable information from informants about changes in cognition, activities of daily living, mood, neuropsychiatric symptoms, and sensory/motor functions. Document individualized risk factors for cognitive decline.

Examination: Conduct a comprehensive examination of cognition, mood, behavior, and a dementia-focused neurologic evaluation using validated tools.

Laboratory tests: Perform tiered, individualized laboratory evaluations, starting with routine tests for all patients.

Structural imaging: Obtain structural brain imaging (MRI preferred, CT as an alternative) to help establish a cause.

Ongoing communication: Engage in ongoing dialogue with patient/care partner to guide them throughout the diagnostic process.

Diagnostic disclosure: Share findings honestly and compassionately, explaining the syndrome, its severity, probable cause, prognosis, treatment options and support resources.

Specialist referral: Refer patients with atypical, uncertain, early-onset, or rapidly progressing symptoms to a dementia subspecialist.

Neuropsychological testing: Use in instances of diagnostic uncertainty or patients with complex clinical profiles. At a minimum, the neuropsychological evaluation should include normed neuropsychological testing of the domains of learning and memory (in particular delayed free and cued recall/recognition), attention, executive function, visuospatial function, and language.

Advanced diagnostic testing: When diagnostic uncertainty remains, obtain additional laboratory tests tailored to individual patient profiles.

Molecular imaging: In a patient with an established cognitive-behavioral syndrome in whom there is continued diagnostic uncertainty regarding cause(s) after structural imaging, a dementia specialist can obtain molecular imaging with fluorodeoxyglucose PET to improve diagnostic accuracy.

Cerebrospinal fluid (CSF) analysis: Utilize CSF biomarkers to evaluate amyloid beta and tau profiles in cases with unresolved diagnostic uncertainty.

Amyloid PET imaging: Perform amyloid PET scans for patients with persistent diagnostic uncertainty after other assessments.

Genetic counseling and testing: Consider genetic testing for patients with strong autosomal dominant family histories and involve a genetic counselor.

 

Future Directions?

Maria C. Carrillo, PhD, chief science officer and medical affairs lead for the Alzheimer’s Association, encourages clinicians to incorporate these guidelines into their practice.

“These guidelines are important because they guide clinicians in the evaluation of memory complaints, which could have many underlying causes. That is the necessary start for an early and accurate Alzheimer’s diagnosis,” Carrillo said in a statement.

Dickerson said the new guidelines do not address blood-based biomarkers “because nobody really feels that they are ready for prime time yet, even though they’re getting rolled out as clinical products.” 

However, the recommendations will be revised as needed. “That’s one of the values of setting this up as a process; whenever any new development occurs, it will be easy to update the guidelines to show where that new test or new biomarker fits in the overall process,” he said.

 

New Appropriate Use Guidance

A separate workgroup, jointly convened by the Alzheimer’s Association and the Society of Nuclear Medicine and Molecular Imaging, has revised appropriate use criteria (AUC) for amyloid PET imaging and developed AUC for tau PET imaging.

They were simultaneously published online in Alzheimer’s & Dementia and The Journal of Nuclear Medicine. They are the first revision since the initial AUC for amyloid PET was introduced in 2013.

“The updated amyloid/tau appropriate use criteria will help ensure these tracers are used in a cost-effective manner and the scan results will be used appropriately to add value to the diagnosis and management of dementia,” said workgroup members Kevin Donohoe, MD, with Beth Israel Deaconess Medical Center, Boston, and Phillip Kuo, MD, with City of Hope National Medical Center, Duarte, California.

The AUC include 17 real-world scenarios in which amyloid or tau PET may be considered, with the two tests considered separately and given their own rating for each scenario.

Overall, the strongest evidence for their use includes assessment and prognosis for people with mild cognitive impairment; assessment of people with dementia when the cause is not clearly known; and determining eligibility for treatment with new disease-modifying therapies, and monitoring response to these treatments, the workgroup said.

“Whereas the prior AUC was written at a time when only the deposition of amyloid could be documented, the new therapeutic agents allow us to demonstrate the actual clearance of amyloid during therapy,” Donohoe and Kuo explained.

“These new therapeutic agents are expensive and, as with most medications, may cause unwanted side effects. The most recent version of the AUC includes information about the appropriate use of amyloid imaging for both documenting the presence of amyloid deposits in the brain, making anti-amyloid therapy an option, as well as documenting the effectiveness of the therapeutic agents as amyloid is (or is not) cleared from the brain,” Donahoe and Kuo noted.

The revised AUC also state that, in most cases, amyloid and tau PET tests should not be used for people who do not have cognitive impairment, even if they carry the APOE4 risk-related gene for Alzheimer’s disease; nonmedical use such as for legal concerns, insurance coverage, or employment screening; and in place of genetic testing in patients suspected of carrying a disease-causing genetic mutation.

In a statement, lead author Gil D. Rabinovici, MD, with University of California, San Francisco, emphasized that the AUC “should be considered guidelines for clinicians, not a substitute for careful clinical judgment that considers the full clinical context for each patient with cognitive complaints.”

This research was funded by the Alzheimer’s Association. Disclosures for guideline authors are available with the original articles.

A version of this article first appeared on Medscape.com.

New evidence–based clinical practice guidelines from the Alzheimer’s Association provide updated recommendations on evaluating individuals suspected of having Alzheimer’s disease and Alzheimer’s disease–related neurodegenerative disorders in both primary and specialty care settings.

This is the first update since 2001 for specialists and the first guideline for primary care physicians. Executive summaries of the guidelines were published in three articles online on December 23 in a special issue of Alzheimer’s & Dementia.

 

What’s New? 

“With this guideline, we expand the scope of prior guidelines by providing recommendations for practicing clinicians on the process from start to finish,” coauthor Brad Dickerson, MD, director of the Massachusetts General Hospital Frontotemporal Disorders Unit and professor of neurology at Harvard Medical School, Boston, said in a statement.

“If clinicians adopt these recommendations and healthcare systems provide adequate resources, outcomes should improve in most patients in most practice settings,” Dickerson added in an interview.

Through a modified-Delphi approach and guideline-development process, an expert workgroup representing primary and specialty care reviewed 7374 publications, of which 133 met inclusion criteria.

Based on the information, the workgroup outlined a three-step patient-centered evaluation process, which includes assessing cognitive functional status, identifying the cognitive-behavioral syndrome based on specific symptoms, and determining the likely brain diseases or conditions causing the symptoms.

 

What Are the Key Recommendations?

The guidelines include 19 “practical” recommendations that are applicable to any practice setting. They capture the core elements of a high-quality evaluation and disclosure process, the author said. Here is a brief summary of the recommendations: 

Initial evaluation: Perform a multitiered evaluation for patients who self-report or whose care partner or clinician reports cognitive, behavioral, or functional changes.

Patient-centered communication: Partner with the patient and/or care partner to establish shared goals for the evaluation process; assess the patient’s capacity to engage in goal setting.

Diagnostic formulation: Use a tiered approach to assessments and tests based on individual presentation, risk factors, and profile, aiming to determine the level of impairment, cognitive-behavioral syndrome, and likely causes and contributing factors.

History taking: Gather reliable information from informants about changes in cognition, activities of daily living, mood, neuropsychiatric symptoms, and sensory/motor functions. Document individualized risk factors for cognitive decline.

Examination: Conduct a comprehensive examination of cognition, mood, behavior, and a dementia-focused neurologic evaluation using validated tools.

Laboratory tests: Perform tiered, individualized laboratory evaluations, starting with routine tests for all patients.

Structural imaging: Obtain structural brain imaging (MRI preferred, CT as an alternative) to help establish a cause.

Ongoing communication: Engage in ongoing dialogue with patient/care partner to guide them throughout the diagnostic process.

Diagnostic disclosure: Share findings honestly and compassionately, explaining the syndrome, its severity, probable cause, prognosis, treatment options and support resources.

Specialist referral: Refer patients with atypical, uncertain, early-onset, or rapidly progressing symptoms to a dementia subspecialist.

Neuropsychological testing: Use in instances of diagnostic uncertainty or patients with complex clinical profiles. At a minimum, the neuropsychological evaluation should include normed neuropsychological testing of the domains of learning and memory (in particular delayed free and cued recall/recognition), attention, executive function, visuospatial function, and language.

Advanced diagnostic testing: When diagnostic uncertainty remains, obtain additional laboratory tests tailored to individual patient profiles.

Molecular imaging: In a patient with an established cognitive-behavioral syndrome in whom there is continued diagnostic uncertainty regarding cause(s) after structural imaging, a dementia specialist can obtain molecular imaging with fluorodeoxyglucose PET to improve diagnostic accuracy.

Cerebrospinal fluid (CSF) analysis: Utilize CSF biomarkers to evaluate amyloid beta and tau profiles in cases with unresolved diagnostic uncertainty.

Amyloid PET imaging: Perform amyloid PET scans for patients with persistent diagnostic uncertainty after other assessments.

Genetic counseling and testing: Consider genetic testing for patients with strong autosomal dominant family histories and involve a genetic counselor.

 

Future Directions?

Maria C. Carrillo, PhD, chief science officer and medical affairs lead for the Alzheimer’s Association, encourages clinicians to incorporate these guidelines into their practice.

“These guidelines are important because they guide clinicians in the evaluation of memory complaints, which could have many underlying causes. That is the necessary start for an early and accurate Alzheimer’s diagnosis,” Carrillo said in a statement.

Dickerson said the new guidelines do not address blood-based biomarkers “because nobody really feels that they are ready for prime time yet, even though they’re getting rolled out as clinical products.” 

However, the recommendations will be revised as needed. “That’s one of the values of setting this up as a process; whenever any new development occurs, it will be easy to update the guidelines to show where that new test or new biomarker fits in the overall process,” he said.

 

New Appropriate Use Guidance

A separate workgroup, jointly convened by the Alzheimer’s Association and the Society of Nuclear Medicine and Molecular Imaging, has revised appropriate use criteria (AUC) for amyloid PET imaging and developed AUC for tau PET imaging.

They were simultaneously published online in Alzheimer’s & Dementia and The Journal of Nuclear Medicine. They are the first revision since the initial AUC for amyloid PET was introduced in 2013.

“The updated amyloid/tau appropriate use criteria will help ensure these tracers are used in a cost-effective manner and the scan results will be used appropriately to add value to the diagnosis and management of dementia,” said workgroup members Kevin Donohoe, MD, with Beth Israel Deaconess Medical Center, Boston, and Phillip Kuo, MD, with City of Hope National Medical Center, Duarte, California.

The AUC include 17 real-world scenarios in which amyloid or tau PET may be considered, with the two tests considered separately and given their own rating for each scenario.

Overall, the strongest evidence for their use includes assessment and prognosis for people with mild cognitive impairment; assessment of people with dementia when the cause is not clearly known; and determining eligibility for treatment with new disease-modifying therapies, and monitoring response to these treatments, the workgroup said.

“Whereas the prior AUC was written at a time when only the deposition of amyloid could be documented, the new therapeutic agents allow us to demonstrate the actual clearance of amyloid during therapy,” Donohoe and Kuo explained.

“These new therapeutic agents are expensive and, as with most medications, may cause unwanted side effects. The most recent version of the AUC includes information about the appropriate use of amyloid imaging for both documenting the presence of amyloid deposits in the brain, making anti-amyloid therapy an option, as well as documenting the effectiveness of the therapeutic agents as amyloid is (or is not) cleared from the brain,” Donahoe and Kuo noted.

The revised AUC also state that, in most cases, amyloid and tau PET tests should not be used for people who do not have cognitive impairment, even if they carry the APOE4 risk-related gene for Alzheimer’s disease; nonmedical use such as for legal concerns, insurance coverage, or employment screening; and in place of genetic testing in patients suspected of carrying a disease-causing genetic mutation.

In a statement, lead author Gil D. Rabinovici, MD, with University of California, San Francisco, emphasized that the AUC “should be considered guidelines for clinicians, not a substitute for careful clinical judgment that considers the full clinical context for each patient with cognitive complaints.”

This research was funded by the Alzheimer’s Association. Disclosures for guideline authors are available with the original articles.

A version of this article first appeared on Medscape.com.

You could be forgiven if you are confused about how blood pressure (BP) affects dementia. First, you read an article extolling the benefits of BP lowering, then a study about how stopping antihypertensives slows cognitive decline in nursing home residents. It’s enough to make you lose your mind.

The Brain Benefits of BP Lowering

It should be stated unequivocally that you should absolutely treat high BP. It may have once been acceptable to state, “The greatest danger to a man with high blood pressure lies in its discovery, because then some fool is certain to try and reduce it.” But those dark days are long behind us.

In these divided times, at least we can agree that we should treat high BP. The cardiovascular (CV) benefits, in and of themselves, justify the decision. But BP’s relationship with dementia is more complex. There are different types of dementia even though we tend to lump them all into one category. Vascular dementia is driven by the same pathophysiology and risk factors as cardiac disease. It’s intuitive that treating hypertension, diabetes, hypercholesterolemia, and smoking will decrease the risk for stroke and limit the damage to the brain that we see with repeated vascular insults. For Alzheimer’s disease, high BP and other CV risk factors seem to increase the risk even if the mechanism is not fully elucidated.

Estimates suggest that if we could lower the prevalence of hypertension by 25%, there would be 160,000 fewer cases of Alzheimer’s disease. But the data are not as robust as one might hope. A 2021 Cochrane review found that hypertension treatment slowed cognitive decline, but the quality of the evidence was low. Short duration of follow-up, dropouts, crossovers, and other problems with the data precluded any certainty. What’s more, hypertension in midlife is associated with cognitive decline and dementia, but its impact in those over age 70 is less clear. Later in life, or once cognitive impairment has already developed, it may be too late for BP lowering to have any impact.

 

Potential Harms of Lowering BP

All this needs to be weighed against the potential harms of treating hypertension. I will reiterate that hypertension should be treated and treated aggressively for the prevention of CV events. But overtreatment, especially in older patients, is associated with hypotension, falls, and syncope. Older patients are also at risk for polypharmacy and drug-drug interactions. 

When it comes to dementia, there is also a concern that overtreating high BP could make things worse. Hypotension and decreased cerebral perfusion could hasten cognitive decline by depriving the brain of that all too necessary oxygen. 

A Korean nationwide survey showed a U-shaped association between BP and Alzheimer’s disease risk in adults (mean age, 67 years), with both high and low BPs associated with a higher risk for Alzheimer’s disease. Though not all studies agree. A post hoc analysis of SPRINT MIND did not find any negative impact of intensive BP lowering on cognitive outcomes or cerebral perfusion in older adults (mean age, 68 years). But it didn’t do much good either. Given the heterogeneity of the data, doubts remain on whether aggressive BP lowering might be detrimental in older patients with comorbidities and preexisting dementia. The obvious corollary then is whether deprescribing hypertensive medications could be beneficial.

A recent publication in JAMA Internal Medicine attempted to address this very question. The cohort study used data from Veterans Affairs nursing home residents (mean age, 78 years) to emulate a randomized trial on deprescribing antihypertensives and cognitive decline. Many of the residents’ cognitive scores worsened over the course of follow-up; however, the decline was less pronounced in the deprescribing group (10% vs 12%). The same group did a similar analysis looking at CV outcomes and found no increased risk for heart attack or stroke with deprescribing BP medications. Taken together, these nursing home data suggest that deprescribing may help slow cognitive decline without the expected trade-off of increased CV events.

 

Deprescribing, Yes or No? 

However, randomized data would obviously be preferable, and these are in short supply. One such trial, the DANTE study, found no benefit to deprescribing in terms of cognition in adults aged 75 years or older with mild cognitive impairment. The study follow-up was only 16 weeks, however, which is hardly enough time to demonstrate any effect, positive or negative. The most that can be said is that it didn’t cause many short-term adverse events.

Perhaps the best conclusion to draw from this somewhat underwhelming collection of data is that lowering high BP is important, but less important the closer we get to the end of life. Hypotension is obviously bad, and overly aggressive BP lowering is going to lead to negative outcomes in older adults because gravity is an unforgiving mistress. 

Deprescribing antihypertensives in older adults is probably not going to cause major negative outcomes, but whether it will do much good in nonhypotensive patients is debatable. The bigger problem is the millions of people with undiagnosed or undertreated hypertension. We would probably have less dementia if we treated hypertension when it does the most good: as a primary-prevention strategy in midlife.

Dr. Labos is a cardiologist at Hôpital Notre-Dame, Montreal, Quebec, Canada. He disclosed no relevant conflicts of interest.

A version of this article first appeared on Medscape.com.

You could be forgiven if you are confused about how blood pressure (BP) affects dementia. First, you read an article extolling the benefits of BP lowering, then a study about how stopping antihypertensives slows cognitive decline in nursing home residents. It’s enough to make you lose your mind.

The Brain Benefits of BP Lowering

It should be stated unequivocally that you should absolutely treat high BP. It may have once been acceptable to state, “The greatest danger to a man with high blood pressure lies in its discovery, because then some fool is certain to try and reduce it.” But those dark days are long behind us.

In these divided times, at least we can agree that we should treat high BP. The cardiovascular (CV) benefits, in and of themselves, justify the decision. But BP’s relationship with dementia is more complex. There are different types of dementia even though we tend to lump them all into one category. Vascular dementia is driven by the same pathophysiology and risk factors as cardiac disease. It’s intuitive that treating hypertension, diabetes, hypercholesterolemia, and smoking will decrease the risk for stroke and limit the damage to the brain that we see with repeated vascular insults. For Alzheimer’s disease, high BP and other CV risk factors seem to increase the risk even if the mechanism is not fully elucidated.

Estimates suggest that if we could lower the prevalence of hypertension by 25%, there would be 160,000 fewer cases of Alzheimer’s disease. But the data are not as robust as one might hope. A 2021 Cochrane review found that hypertension treatment slowed cognitive decline, but the quality of the evidence was low. Short duration of follow-up, dropouts, crossovers, and other problems with the data precluded any certainty. What’s more, hypertension in midlife is associated with cognitive decline and dementia, but its impact in those over age 70 is less clear. Later in life, or once cognitive impairment has already developed, it may be too late for BP lowering to have any impact.

 

Potential Harms of Lowering BP

All this needs to be weighed against the potential harms of treating hypertension. I will reiterate that hypertension should be treated and treated aggressively for the prevention of CV events. But overtreatment, especially in older patients, is associated with hypotension, falls, and syncope. Older patients are also at risk for polypharmacy and drug-drug interactions. 

When it comes to dementia, there is also a concern that overtreating high BP could make things worse. Hypotension and decreased cerebral perfusion could hasten cognitive decline by depriving the brain of that all too necessary oxygen. 

A Korean nationwide survey showed a U-shaped association between BP and Alzheimer’s disease risk in adults (mean age, 67 years), with both high and low BPs associated with a higher risk for Alzheimer’s disease. Though not all studies agree. A post hoc analysis of SPRINT MIND did not find any negative impact of intensive BP lowering on cognitive outcomes or cerebral perfusion in older adults (mean age, 68 years). But it didn’t do much good either. Given the heterogeneity of the data, doubts remain on whether aggressive BP lowering might be detrimental in older patients with comorbidities and preexisting dementia. The obvious corollary then is whether deprescribing hypertensive medications could be beneficial.

A recent publication in JAMA Internal Medicine attempted to address this very question. The cohort study used data from Veterans Affairs nursing home residents (mean age, 78 years) to emulate a randomized trial on deprescribing antihypertensives and cognitive decline. Many of the residents’ cognitive scores worsened over the course of follow-up; however, the decline was less pronounced in the deprescribing group (10% vs 12%). The same group did a similar analysis looking at CV outcomes and found no increased risk for heart attack or stroke with deprescribing BP medications. Taken together, these nursing home data suggest that deprescribing may help slow cognitive decline without the expected trade-off of increased CV events.

 

Deprescribing, Yes or No? 

However, randomized data would obviously be preferable, and these are in short supply. One such trial, the DANTE study, found no benefit to deprescribing in terms of cognition in adults aged 75 years or older with mild cognitive impairment. The study follow-up was only 16 weeks, however, which is hardly enough time to demonstrate any effect, positive or negative. The most that can be said is that it didn’t cause many short-term adverse events.

Perhaps the best conclusion to draw from this somewhat underwhelming collection of data is that lowering high BP is important, but less important the closer we get to the end of life. Hypotension is obviously bad, and overly aggressive BP lowering is going to lead to negative outcomes in older adults because gravity is an unforgiving mistress. 

Deprescribing antihypertensives in older adults is probably not going to cause major negative outcomes, but whether it will do much good in nonhypotensive patients is debatable. The bigger problem is the millions of people with undiagnosed or undertreated hypertension. We would probably have less dementia if we treated hypertension when it does the most good: as a primary-prevention strategy in midlife.

Dr. Labos is a cardiologist at Hôpital Notre-Dame, Montreal, Quebec, Canada. He disclosed no relevant conflicts of interest.

A version of this article first appeared on Medscape.com.

You could be forgiven if you are confused about how blood pressure (BP) affects dementia. First, you read an article extolling the benefits of BP lowering, then a study about how stopping antihypertensives slows cognitive decline in nursing home residents. It’s enough to make you lose your mind.

The Brain Benefits of BP Lowering

It should be stated unequivocally that you should absolutely treat high BP. It may have once been acceptable to state, “The greatest danger to a man with high blood pressure lies in its discovery, because then some fool is certain to try and reduce it.” But those dark days are long behind us.

In these divided times, at least we can agree that we should treat high BP. The cardiovascular (CV) benefits, in and of themselves, justify the decision. But BP’s relationship with dementia is more complex. There are different types of dementia even though we tend to lump them all into one category. Vascular dementia is driven by the same pathophysiology and risk factors as cardiac disease. It’s intuitive that treating hypertension, diabetes, hypercholesterolemia, and smoking will decrease the risk for stroke and limit the damage to the brain that we see with repeated vascular insults. For Alzheimer’s disease, high BP and other CV risk factors seem to increase the risk even if the mechanism is not fully elucidated.

Estimates suggest that if we could lower the prevalence of hypertension by 25%, there would be 160,000 fewer cases of Alzheimer’s disease. But the data are not as robust as one might hope. A 2021 Cochrane review found that hypertension treatment slowed cognitive decline, but the quality of the evidence was low. Short duration of follow-up, dropouts, crossovers, and other problems with the data precluded any certainty. What’s more, hypertension in midlife is associated with cognitive decline and dementia, but its impact in those over age 70 is less clear. Later in life, or once cognitive impairment has already developed, it may be too late for BP lowering to have any impact.

 

Potential Harms of Lowering BP

All this needs to be weighed against the potential harms of treating hypertension. I will reiterate that hypertension should be treated and treated aggressively for the prevention of CV events. But overtreatment, especially in older patients, is associated with hypotension, falls, and syncope. Older patients are also at risk for polypharmacy and drug-drug interactions. 

When it comes to dementia, there is also a concern that overtreating high BP could make things worse. Hypotension and decreased cerebral perfusion could hasten cognitive decline by depriving the brain of that all too necessary oxygen. 

A Korean nationwide survey showed a U-shaped association between BP and Alzheimer’s disease risk in adults (mean age, 67 years), with both high and low BPs associated with a higher risk for Alzheimer’s disease. Though not all studies agree. A post hoc analysis of SPRINT MIND did not find any negative impact of intensive BP lowering on cognitive outcomes or cerebral perfusion in older adults (mean age, 68 years). But it didn’t do much good either. Given the heterogeneity of the data, doubts remain on whether aggressive BP lowering might be detrimental in older patients with comorbidities and preexisting dementia. The obvious corollary then is whether deprescribing hypertensive medications could be beneficial.

A recent publication in JAMA Internal Medicine attempted to address this very question. The cohort study used data from Veterans Affairs nursing home residents (mean age, 78 years) to emulate a randomized trial on deprescribing antihypertensives and cognitive decline. Many of the residents’ cognitive scores worsened over the course of follow-up; however, the decline was less pronounced in the deprescribing group (10% vs 12%). The same group did a similar analysis looking at CV outcomes and found no increased risk for heart attack or stroke with deprescribing BP medications. Taken together, these nursing home data suggest that deprescribing may help slow cognitive decline without the expected trade-off of increased CV events.

 

Deprescribing, Yes or No? 

However, randomized data would obviously be preferable, and these are in short supply. One such trial, the DANTE study, found no benefit to deprescribing in terms of cognition in adults aged 75 years or older with mild cognitive impairment. The study follow-up was only 16 weeks, however, which is hardly enough time to demonstrate any effect, positive or negative. The most that can be said is that it didn’t cause many short-term adverse events.

Perhaps the best conclusion to draw from this somewhat underwhelming collection of data is that lowering high BP is important, but less important the closer we get to the end of life. Hypotension is obviously bad, and overly aggressive BP lowering is going to lead to negative outcomes in older adults because gravity is an unforgiving mistress. 

Deprescribing antihypertensives in older adults is probably not going to cause major negative outcomes, but whether it will do much good in nonhypotensive patients is debatable. The bigger problem is the millions of people with undiagnosed or undertreated hypertension. We would probably have less dementia if we treated hypertension when it does the most good: as a primary-prevention strategy in midlife.

Dr. Labos is a cardiologist at Hôpital Notre-Dame, Montreal, Quebec, Canada. He disclosed no relevant conflicts of interest.

A version of this article first appeared on Medscape.com.

TOPLINE:

In 2022, autoimmune diseases affected over 15 million individuals in the United States, with women nearly twice as likely to be affected as men and more than one third of affected individuals having more than one autoimmune condition.

METHODOLOGY:

• Researchers used electronic health record (EHR) data from six healthcare systems in the United States between 2011 and 2022 to estimate the prevalence of autoimmune diseases according to sex and age.
• They selected 105 autoimmune diseases from the textbook The Autoimmune Diseases and estimated their prevalence in more than 10 million individuals from these healthcare systems; these statistics were subsequently extrapolated to an estimated US population of 333.3 million.
• An individual was considered to have a diagnosis of an autoimmune disease if they had at least two diagnosis codes for the condition, with the codes being at least 30 days apart.
• A software program was developed to compute the prevalence of autoimmune diseases alone and in aggregate, enabling other researchers to replicate or modify the analysis over time.

TAKEAWAY:

• More than 15 million people, accounting for 4.6% of the US population, were diagnosed with at least one autoimmune disease from January 2011 to June 2022; 34% were diagnosed with more than one autoimmune disease.
• Sex-stratified analysis revealed that 63% of patients diagnosed with autoimmune disease were women, and only 37% were men, establishing a female-to-male ratio of 1.7:1; age-stratified analysis revealed increasing prevalence of autoimmune conditions with age, peaking in individuals aged ≥ 65 years.
• Among individuals with autoimmune diseases, 65% of patients had one condition, whereas 24% had two, 8% had three, and 2% had four or more autoimmune diseases (does not add to 100% due to rounding).
• Rheumatoid arthritis emerged as the most prevalent autoimmune disease, followed by psoriasis, type 1 diabetes, Grave’s disease, and autoimmune thyroiditis; 19 of the top 20 most prevalent autoimmune diseases occurred more frequently in women.

IN PRACTICE:

“Accurate data on the prevalence of autoimmune diseases as a category of disease and for individual autoimmune diseases are needed to further clinical and basic research to improve diagnosis, biomarkers, and therapies for these diseases, which significantly impact the US population,” the authors wrote.

SOURCE:

The study was led by Aaron H. Abend, Autoimmune Registry, Guilford, Connecticut, and was published online in The Journal of Clinical Investigation.

LIMITATIONS:

The use of EHR data presented several challenges, including potential inaccuracies in diagnosis codes and the possibility of missing patients with single diagnosis codes because of the two-code requirement. Certain autoimmune diseases evolve over time and involve nonspecific clinical signs and symptoms that can mimic other diseases, potentially resulting in underdiagnosis. Moreover, rare diseases lacking specific diagnosis codes may have been underrepresented.

DISCLOSURES:

The study received support from Autoimmune Registry; the National Institutes of Health National Center for Advancing Translational Sciences; the National Heart, Lung, and Blood Institute; and other sources. Information on potential conflicts of interest was not disclosed.

This article was created using several editorial tools, including artificial intelligence, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

TOPLINE:

In 2022, autoimmune diseases affected over 15 million individuals in the United States, with women nearly twice as likely to be affected as men and more than one third of affected individuals having more than one autoimmune condition.

METHODOLOGY:

• Researchers used electronic health record (EHR) data from six healthcare systems in the United States between 2011 and 2022 to estimate the prevalence of autoimmune diseases according to sex and age.
• They selected 105 autoimmune diseases from the textbook The Autoimmune Diseases and estimated their prevalence in more than 10 million individuals from these healthcare systems; these statistics were subsequently extrapolated to an estimated US population of 333.3 million.
• An individual was considered to have a diagnosis of an autoimmune disease if they had at least two diagnosis codes for the condition, with the codes being at least 30 days apart.
• A software program was developed to compute the prevalence of autoimmune diseases alone and in aggregate, enabling other researchers to replicate or modify the analysis over time.

TAKEAWAY:

• More than 15 million people, accounting for 4.6% of the US population, were diagnosed with at least one autoimmune disease from January 2011 to June 2022; 34% were diagnosed with more than one autoimmune disease.
• Sex-stratified analysis revealed that 63% of patients diagnosed with autoimmune disease were women, and only 37% were men, establishing a female-to-male ratio of 1.7:1; age-stratified analysis revealed increasing prevalence of autoimmune conditions with age, peaking in individuals aged ≥ 65 years.
• Among individuals with autoimmune diseases, 65% of patients had one condition, whereas 24% had two, 8% had three, and 2% had four or more autoimmune diseases (does not add to 100% due to rounding).
• Rheumatoid arthritis emerged as the most prevalent autoimmune disease, followed by psoriasis, type 1 diabetes, Grave’s disease, and autoimmune thyroiditis; 19 of the top 20 most prevalent autoimmune diseases occurred more frequently in women.

IN PRACTICE:

“Accurate data on the prevalence of autoimmune diseases as a category of disease and for individual autoimmune diseases are needed to further clinical and basic research to improve diagnosis, biomarkers, and therapies for these diseases, which significantly impact the US population,” the authors wrote.

SOURCE:

The study was led by Aaron H. Abend, Autoimmune Registry, Guilford, Connecticut, and was published online in The Journal of Clinical Investigation.

LIMITATIONS:

The use of EHR data presented several challenges, including potential inaccuracies in diagnosis codes and the possibility of missing patients with single diagnosis codes because of the two-code requirement. Certain autoimmune diseases evolve over time and involve nonspecific clinical signs and symptoms that can mimic other diseases, potentially resulting in underdiagnosis. Moreover, rare diseases lacking specific diagnosis codes may have been underrepresented.

DISCLOSURES:

The study received support from Autoimmune Registry; the National Institutes of Health National Center for Advancing Translational Sciences; the National Heart, Lung, and Blood Institute; and other sources. Information on potential conflicts of interest was not disclosed.

This article was created using several editorial tools, including artificial intelligence, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

TOPLINE:

In 2022, autoimmune diseases affected over 15 million individuals in the United States, with women nearly twice as likely to be affected as men and more than one third of affected individuals having more than one autoimmune condition.

METHODOLOGY:

• Researchers used electronic health record (EHR) data from six healthcare systems in the United States between 2011 and 2022 to estimate the prevalence of autoimmune diseases according to sex and age.
• They selected 105 autoimmune diseases from the textbook The Autoimmune Diseases and estimated their prevalence in more than 10 million individuals from these healthcare systems; these statistics were subsequently extrapolated to an estimated US population of 333.3 million.
• An individual was considered to have a diagnosis of an autoimmune disease if they had at least two diagnosis codes for the condition, with the codes being at least 30 days apart.
• A software program was developed to compute the prevalence of autoimmune diseases alone and in aggregate, enabling other researchers to replicate or modify the analysis over time.

TAKEAWAY:

• More than 15 million people, accounting for 4.6% of the US population, were diagnosed with at least one autoimmune disease from January 2011 to June 2022; 34% were diagnosed with more than one autoimmune disease.
• Sex-stratified analysis revealed that 63% of patients diagnosed with autoimmune disease were women, and only 37% were men, establishing a female-to-male ratio of 1.7:1; age-stratified analysis revealed increasing prevalence of autoimmune conditions with age, peaking in individuals aged ≥ 65 years.
• Among individuals with autoimmune diseases, 65% of patients had one condition, whereas 24% had two, 8% had three, and 2% had four or more autoimmune diseases (does not add to 100% due to rounding).
• Rheumatoid arthritis emerged as the most prevalent autoimmune disease, followed by psoriasis, type 1 diabetes, Grave’s disease, and autoimmune thyroiditis; 19 of the top 20 most prevalent autoimmune diseases occurred more frequently in women.

IN PRACTICE:

“Accurate data on the prevalence of autoimmune diseases as a category of disease and for individual autoimmune diseases are needed to further clinical and basic research to improve diagnosis, biomarkers, and therapies for these diseases, which significantly impact the US population,” the authors wrote.

SOURCE:

The study was led by Aaron H. Abend, Autoimmune Registry, Guilford, Connecticut, and was published online in The Journal of Clinical Investigation.

LIMITATIONS:

The use of EHR data presented several challenges, including potential inaccuracies in diagnosis codes and the possibility of missing patients with single diagnosis codes because of the two-code requirement. Certain autoimmune diseases evolve over time and involve nonspecific clinical signs and symptoms that can mimic other diseases, potentially resulting in underdiagnosis. Moreover, rare diseases lacking specific diagnosis codes may have been underrepresented.

DISCLOSURES:

The study received support from Autoimmune Registry; the National Institutes of Health National Center for Advancing Translational Sciences; the National Heart, Lung, and Blood Institute; and other sources. Information on potential conflicts of interest was not disclosed.

This article was created using several editorial tools, including artificial intelligence, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

Children with asthma scored significantly lower than those without asthma on measures of episodic memory, based on longitudinal data from nearly 500 individuals.

Animal models have shown associations between asthma and memory problems, but data for children are lacking, wrote Nicholas J. Christopher-Hayes, MA, of the University of California, Davis, and colleagues.

“Asthma is very frequent among children, and there is mounting evidence from rodent models that asthma may result in neural injury in the hippocampus, which in turn may cause memory loss,” Christopher-Hayes said in an interview. “Although there is also a good amount of research with older adults, very little research has been done with children, the period that is most frequently linked to asthma onset,” he said. Therefore, the researchers leveraged a large national study on child development to examine development of memory as a function of asthma exposure.

In this study published in JAMA Network Open, the researchers conducted both a longitudinal and cross-sectional analysis of data from the Adolescent Brain Cognitive Development Study, which began in 2015. Children were enrolled at ages 9-10 years with a follow-up assessment 1-2 years later.

The participants were categorized as early childhood-onset asthma (asthma at baseline and follow-up), later childhood-onset asthma (asthma at follow-up only), or no asthma history. The primary outcome of the longitudinal analysis was episodic memory. Approximately half of the participants were boys, and slightly more than half were White.

Among 474 children reviewed in the longitudinal analysis, 135 had early-onset asthma, 102 had later-onset asthma, and 237 had no asthma and served as control individuals. Overall, those with early-onset asthma showed significantly lower rates of longitudinal memory improvements at follow-up compared with the comparison group (P < .01).

Developmental memory improvement in children with later-onset asthma was not significantly different from the control individuals. 

Secondary outcomes included processing speed and inhibition, and attention. In a cross-sectional analysis with a larger sample of 2062 children from the same database (1031 with any asthma), those with asthma scored significantly lower on measures not only of episodic memory but also processing speed and inhibition/attention than children with no asthma, with P values of .04, .01, and .02, respectively.

The results were limited by several factors, including the reliance on parent reports for indicators of asthma and the lack of data on the potential effect of prescription corticosteroid use on neurocognitive development, the researchers noted.

The mechanism behind the association remains unclear; the inflammation associated with asthma may disrupt neural processing and manifest as cognitive dysfunction, as has been seen in rodent models of asthma, the researchers wrote. “It is possible that associations between asthma and developmental trajectories emerge earlier for memory, perhaps due to its sensitivity to subtle hippocampal injury,” they noted.

Longer follow-up studies are needed to fully understand how childhood asthma predicts memory declines or difficulties in childhood and beyond, said Christopher-Hayes. “We also need additional studies to understand why children who were diagnosed earlier and had asthma for longer seem to be particularly affected,” he said.

The results of this study were consistent with previous findings and therefore not surprising, senior author Simona Ghetti, PhD, a professor of psychology at the University of California, Davis, said in an interview. However, the finding that the extent of exposure to asthma was associated with slower memory improvement in childhood was striking, she said. That children with an earlier asthma onset who had disease indicators for a longer period showed a slower development of memory over time, suggests that asthma exposure may affect the developmental trajectory of memory, Ghetti noted. 

“Recommendations to clinicians are premature because we need a better understanding of the boundary conditions, such as the minimal level of asthma exposure that might generate memory difficulties,” said Ghetti.

“Nevertheless, our results underscore the importance of looking at asthma as a potential source of cognitive difficulty in children,” she said.

 

Asthma’s Extensive Effect

Evidence is mounting that a diagnosis of asthma may have implications outside the pulmonary system, Diego J. Maselli, MD, professor and chief of the Division of Pulmonary Diseases & Critical Care at UT Health, San Antonio, said in an interview. 

“Asthmatics may be at risk of nasal polyps, allergic rhinitis, and other allergic conditions, but there is emerging of evidence inflammation associated with asthma may affect other organ systems,” said Maselli, who was not involved in the study.

“For example, chronic inflammation in asthmatics may increase the risk of cardiovascular disease,” he said.

Although less is known about the effects of asthma on the nervous system, animal models suggest that inflammation associated with asthma may result in neuronal injury and potential effects on memory, said Maselli.

The findings of this study provide evidence of potential detrimental effects on the memory of children with asthma but should be interpreted with caution, Maselli said. “Children with chronic medical conditions may have an inherent disadvantage compared with their peers due to the burden of their disease, medication utilization and side effects, absenteeism from school, physical limitations, and other disease-specific circumstances,” he noted.

“Uncontrolled asthma, in particular, has strong links to low socioeconomic factors that are closely tied to access to adequate medical care, nutrition, educational institutions, and other relevant contributors to normal cognitive development,” Maselli said. Although the authors account for some of these socioeconomic factors by evaluating income and race, other variables may have influenced the results, he added.

Overall, this study’s findings suggested that the diagnosis of asthma in children may be associated with memory deficits and may influence neurodevelopment; however, more research is needed to determine whether the findings are replicated in other cohorts, said Maselli. “In particular, evaluating the effects of the severity of asthma and different asthma endotypes would be crucial to identify children with a higher risk of memory or cognitive deficits and confirm these associations,” he said.

This study was funded by the Memory and Plasticity Program at the University of California, Davis, and by a Learning, Memory, and Plasticity Training Program Fellowship grant from the National Institutes of Health. The researchers and Maselli had no financial conflicts to disclose. 

 

A version of this article appeared on Medscape.com.

Children with asthma scored significantly lower than those without asthma on measures of episodic memory, based on longitudinal data from nearly 500 individuals.

Animal models have shown associations between asthma and memory problems, but data for children are lacking, wrote Nicholas J. Christopher-Hayes, MA, of the University of California, Davis, and colleagues.

“Asthma is very frequent among children, and there is mounting evidence from rodent models that asthma may result in neural injury in the hippocampus, which in turn may cause memory loss,” Christopher-Hayes said in an interview. “Although there is also a good amount of research with older adults, very little research has been done with children, the period that is most frequently linked to asthma onset,” he said. Therefore, the researchers leveraged a large national study on child development to examine development of memory as a function of asthma exposure.

In this study published in JAMA Network Open, the researchers conducted both a longitudinal and cross-sectional analysis of data from the Adolescent Brain Cognitive Development Study, which began in 2015. Children were enrolled at ages 9-10 years with a follow-up assessment 1-2 years later.

The participants were categorized as early childhood-onset asthma (asthma at baseline and follow-up), later childhood-onset asthma (asthma at follow-up only), or no asthma history. The primary outcome of the longitudinal analysis was episodic memory. Approximately half of the participants were boys, and slightly more than half were White.

Among 474 children reviewed in the longitudinal analysis, 135 had early-onset asthma, 102 had later-onset asthma, and 237 had no asthma and served as control individuals. Overall, those with early-onset asthma showed significantly lower rates of longitudinal memory improvements at follow-up compared with the comparison group (P < .01).

Developmental memory improvement in children with later-onset asthma was not significantly different from the control individuals. 

Secondary outcomes included processing speed and inhibition, and attention. In a cross-sectional analysis with a larger sample of 2062 children from the same database (1031 with any asthma), those with asthma scored significantly lower on measures not only of episodic memory but also processing speed and inhibition/attention than children with no asthma, with P values of .04, .01, and .02, respectively.

The results were limited by several factors, including the reliance on parent reports for indicators of asthma and the lack of data on the potential effect of prescription corticosteroid use on neurocognitive development, the researchers noted.

The mechanism behind the association remains unclear; the inflammation associated with asthma may disrupt neural processing and manifest as cognitive dysfunction, as has been seen in rodent models of asthma, the researchers wrote. “It is possible that associations between asthma and developmental trajectories emerge earlier for memory, perhaps due to its sensitivity to subtle hippocampal injury,” they noted.

Longer follow-up studies are needed to fully understand how childhood asthma predicts memory declines or difficulties in childhood and beyond, said Christopher-Hayes. “We also need additional studies to understand why children who were diagnosed earlier and had asthma for longer seem to be particularly affected,” he said.

The results of this study were consistent with previous findings and therefore not surprising, senior author Simona Ghetti, PhD, a professor of psychology at the University of California, Davis, said in an interview. However, the finding that the extent of exposure to asthma was associated with slower memory improvement in childhood was striking, she said. That children with an earlier asthma onset who had disease indicators for a longer period showed a slower development of memory over time, suggests that asthma exposure may affect the developmental trajectory of memory, Ghetti noted. 

“Recommendations to clinicians are premature because we need a better understanding of the boundary conditions, such as the minimal level of asthma exposure that might generate memory difficulties,” said Ghetti.

“Nevertheless, our results underscore the importance of looking at asthma as a potential source of cognitive difficulty in children,” she said.

 

Asthma’s Extensive Effect

Evidence is mounting that a diagnosis of asthma may have implications outside the pulmonary system, Diego J. Maselli, MD, professor and chief of the Division of Pulmonary Diseases & Critical Care at UT Health, San Antonio, said in an interview. 

“Asthmatics may be at risk of nasal polyps, allergic rhinitis, and other allergic conditions, but there is emerging of evidence inflammation associated with asthma may affect other organ systems,” said Maselli, who was not involved in the study.

“For example, chronic inflammation in asthmatics may increase the risk of cardiovascular disease,” he said.

Although less is known about the effects of asthma on the nervous system, animal models suggest that inflammation associated with asthma may result in neuronal injury and potential effects on memory, said Maselli.

The findings of this study provide evidence of potential detrimental effects on the memory of children with asthma but should be interpreted with caution, Maselli said. “Children with chronic medical conditions may have an inherent disadvantage compared with their peers due to the burden of their disease, medication utilization and side effects, absenteeism from school, physical limitations, and other disease-specific circumstances,” he noted.

“Uncontrolled asthma, in particular, has strong links to low socioeconomic factors that are closely tied to access to adequate medical care, nutrition, educational institutions, and other relevant contributors to normal cognitive development,” Maselli said. Although the authors account for some of these socioeconomic factors by evaluating income and race, other variables may have influenced the results, he added.

Overall, this study’s findings suggested that the diagnosis of asthma in children may be associated with memory deficits and may influence neurodevelopment; however, more research is needed to determine whether the findings are replicated in other cohorts, said Maselli. “In particular, evaluating the effects of the severity of asthma and different asthma endotypes would be crucial to identify children with a higher risk of memory or cognitive deficits and confirm these associations,” he said.

This study was funded by the Memory and Plasticity Program at the University of California, Davis, and by a Learning, Memory, and Plasticity Training Program Fellowship grant from the National Institutes of Health. The researchers and Maselli had no financial conflicts to disclose. 

 

A version of this article appeared on Medscape.com.

Children with asthma scored significantly lower than those without asthma on measures of episodic memory, based on longitudinal data from nearly 500 individuals.

Animal models have shown associations between asthma and memory problems, but data for children are lacking, wrote Nicholas J. Christopher-Hayes, MA, of the University of California, Davis, and colleagues.

“Asthma is very frequent among children, and there is mounting evidence from rodent models that asthma may result in neural injury in the hippocampus, which in turn may cause memory loss,” Christopher-Hayes said in an interview. “Although there is also a good amount of research with older adults, very little research has been done with children, the period that is most frequently linked to asthma onset,” he said. Therefore, the researchers leveraged a large national study on child development to examine development of memory as a function of asthma exposure.

In this study published in JAMA Network Open, the researchers conducted both a longitudinal and cross-sectional analysis of data from the Adolescent Brain Cognitive Development Study, which began in 2015. Children were enrolled at ages 9-10 years with a follow-up assessment 1-2 years later.

The participants were categorized as early childhood-onset asthma (asthma at baseline and follow-up), later childhood-onset asthma (asthma at follow-up only), or no asthma history. The primary outcome of the longitudinal analysis was episodic memory. Approximately half of the participants were boys, and slightly more than half were White.

Among 474 children reviewed in the longitudinal analysis, 135 had early-onset asthma, 102 had later-onset asthma, and 237 had no asthma and served as control individuals. Overall, those with early-onset asthma showed significantly lower rates of longitudinal memory improvements at follow-up compared with the comparison group (P < .01).

Developmental memory improvement in children with later-onset asthma was not significantly different from the control individuals. 

Secondary outcomes included processing speed and inhibition, and attention. In a cross-sectional analysis with a larger sample of 2062 children from the same database (1031 with any asthma), those with asthma scored significantly lower on measures not only of episodic memory but also processing speed and inhibition/attention than children with no asthma, with P values of .04, .01, and .02, respectively.

The results were limited by several factors, including the reliance on parent reports for indicators of asthma and the lack of data on the potential effect of prescription corticosteroid use on neurocognitive development, the researchers noted.

The mechanism behind the association remains unclear; the inflammation associated with asthma may disrupt neural processing and manifest as cognitive dysfunction, as has been seen in rodent models of asthma, the researchers wrote. “It is possible that associations between asthma and developmental trajectories emerge earlier for memory, perhaps due to its sensitivity to subtle hippocampal injury,” they noted.

Longer follow-up studies are needed to fully understand how childhood asthma predicts memory declines or difficulties in childhood and beyond, said Christopher-Hayes. “We also need additional studies to understand why children who were diagnosed earlier and had asthma for longer seem to be particularly affected,” he said.

The results of this study were consistent with previous findings and therefore not surprising, senior author Simona Ghetti, PhD, a professor of psychology at the University of California, Davis, said in an interview. However, the finding that the extent of exposure to asthma was associated with slower memory improvement in childhood was striking, she said. That children with an earlier asthma onset who had disease indicators for a longer period showed a slower development of memory over time, suggests that asthma exposure may affect the developmental trajectory of memory, Ghetti noted. 

“Recommendations to clinicians are premature because we need a better understanding of the boundary conditions, such as the minimal level of asthma exposure that might generate memory difficulties,” said Ghetti.

“Nevertheless, our results underscore the importance of looking at asthma as a potential source of cognitive difficulty in children,” she said.

 

Asthma’s Extensive Effect

Evidence is mounting that a diagnosis of asthma may have implications outside the pulmonary system, Diego J. Maselli, MD, professor and chief of the Division of Pulmonary Diseases & Critical Care at UT Health, San Antonio, said in an interview. 

“Asthmatics may be at risk of nasal polyps, allergic rhinitis, and other allergic conditions, but there is emerging of evidence inflammation associated with asthma may affect other organ systems,” said Maselli, who was not involved in the study.

“For example, chronic inflammation in asthmatics may increase the risk of cardiovascular disease,” he said.

Although less is known about the effects of asthma on the nervous system, animal models suggest that inflammation associated with asthma may result in neuronal injury and potential effects on memory, said Maselli.

The findings of this study provide evidence of potential detrimental effects on the memory of children with asthma but should be interpreted with caution, Maselli said. “Children with chronic medical conditions may have an inherent disadvantage compared with their peers due to the burden of their disease, medication utilization and side effects, absenteeism from school, physical limitations, and other disease-specific circumstances,” he noted.

“Uncontrolled asthma, in particular, has strong links to low socioeconomic factors that are closely tied to access to adequate medical care, nutrition, educational institutions, and other relevant contributors to normal cognitive development,” Maselli said. Although the authors account for some of these socioeconomic factors by evaluating income and race, other variables may have influenced the results, he added.

Overall, this study’s findings suggested that the diagnosis of asthma in children may be associated with memory deficits and may influence neurodevelopment; however, more research is needed to determine whether the findings are replicated in other cohorts, said Maselli. “In particular, evaluating the effects of the severity of asthma and different asthma endotypes would be crucial to identify children with a higher risk of memory or cognitive deficits and confirm these associations,” he said.

This study was funded by the Memory and Plasticity Program at the University of California, Davis, and by a Learning, Memory, and Plasticity Training Program Fellowship grant from the National Institutes of Health. The researchers and Maselli had no financial conflicts to disclose. 

 

A version of this article appeared on Medscape.com.

TOPLINE:

Risk for dementia is nearly 80% higher in stroke survivors than in those without stroke, a new study reveals. The data suggest risk declines within 1 year after stroke but remains elevated for up to 20 years.

METHODOLOGY:

• Researchers conducted a population-wide analysis of over 15 million people in Canada between 2002 and 2022. The study focused on adults hospitalized for ischemic stroke, intracerebral hemorrhage, or acute myocardial infarction (AMI).
• Of 175,980 stroke survivors, 99% were matched 1:1 to residents without stroke on the basis of age, sex, rural residence, neighborhood deprivation, and vascular comorbidities. In addition, 90% of patients were matched to those with AMI.
• Incident dementia diagnoses were tracked starting 90 days after stroke until death, emigration, or the end of the study, using a validated algorithm based on hospitalization for dementia, prescriptions for cholinesterase inhibitors, or physician claims within 2 years.
• The mean follow-up duration was 5.6 years.

TAKEAWAY:

• Among stroke survivors, 19% were diagnosed with dementia vs 12.5% in the reference population. The dementia rate per 100 person-years was higher among stroke survivors than in the reference population over the entire follow-up period (3.34 vs 1.89).
• Over the entire study period, dementia was 76% more likely among stroke patients (hazard ratio [HR], 1.76; 95% CI, 1.73-1.79) and 82% more likely in the AMI cohort (HR, 1.82; 95% CI, 1.79-1.85) than in the reference population.
• Time-varying analysis revealed that dementia risk was highest within the first year after stroke, with a > 2.5-fold increase at 6 months (HR, 2.51; 95% CI, 2.42-2.59), which decreased to a 1.5-fold increase at 5 years (HR, 1.51; 95% CI, 1.48-1.56) but remained elevated compared with the reference population even 20 years after the index stroke.
• Recurrent stroke was associated with an approximately threefold increased risk for dementia (single recurrent stroke adjusted HR, 2.64; 95% CI, 2.54-2.74; multiple recurrent strokes adjusted HR, 3.05; 95% CI, 2.81-3.33).

IN PRACTICE:

“While much research has been focused on reducing the risk of a second stroke, our findings make it clear that more research also is needed on developing interventions to help prevent dementia after stroke,” lead author Raed A. Joundi, MD, DPhil, McMaster University, Hamilton, Ontario, Canada, said in a press release.

“There is a need to accelerate the implementation of promising interventions or multipronged approaches into large randomized controlled trials to lower the risk of dementia,” the investigators wrote.
 

SOURCE:

The study was published online on December 4 in Neurology.

LIMITATIONS:

The study’s limitations included reliance on administrative coding without imaging data, potential underestimation of mild dementia, and lack of granular information on stroke severity, disability, and prestroke cognitive decline. While adjustments were made for healthcare contact and secondary prevention medications, residual biases may have persisted.

DISCLOSURES:

This study received funding from the Canada Brain Research Fund, Heart & Stroke Foundation of Canada, and Canadian Stroke Consortium. Two authors hold awards and positions from national organizations and academic institutions in Canada. Additional details are provided in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

TOPLINE:

Risk for dementia is nearly 80% higher in stroke survivors than in those without stroke, a new study reveals. The data suggest risk declines within 1 year after stroke but remains elevated for up to 20 years.

METHODOLOGY:

• Researchers conducted a population-wide analysis of over 15 million people in Canada between 2002 and 2022. The study focused on adults hospitalized for ischemic stroke, intracerebral hemorrhage, or acute myocardial infarction (AMI).
• Of 175,980 stroke survivors, 99% were matched 1:1 to residents without stroke on the basis of age, sex, rural residence, neighborhood deprivation, and vascular comorbidities. In addition, 90% of patients were matched to those with AMI.
• Incident dementia diagnoses were tracked starting 90 days after stroke until death, emigration, or the end of the study, using a validated algorithm based on hospitalization for dementia, prescriptions for cholinesterase inhibitors, or physician claims within 2 years.
• The mean follow-up duration was 5.6 years.

TAKEAWAY:

• Among stroke survivors, 19% were diagnosed with dementia vs 12.5% in the reference population. The dementia rate per 100 person-years was higher among stroke survivors than in the reference population over the entire follow-up period (3.34 vs 1.89).
• Over the entire study period, dementia was 76% more likely among stroke patients (hazard ratio [HR], 1.76; 95% CI, 1.73-1.79) and 82% more likely in the AMI cohort (HR, 1.82; 95% CI, 1.79-1.85) than in the reference population.
• Time-varying analysis revealed that dementia risk was highest within the first year after stroke, with a > 2.5-fold increase at 6 months (HR, 2.51; 95% CI, 2.42-2.59), which decreased to a 1.5-fold increase at 5 years (HR, 1.51; 95% CI, 1.48-1.56) but remained elevated compared with the reference population even 20 years after the index stroke.
• Recurrent stroke was associated with an approximately threefold increased risk for dementia (single recurrent stroke adjusted HR, 2.64; 95% CI, 2.54-2.74; multiple recurrent strokes adjusted HR, 3.05; 95% CI, 2.81-3.33).

IN PRACTICE:

“While much research has been focused on reducing the risk of a second stroke, our findings make it clear that more research also is needed on developing interventions to help prevent dementia after stroke,” lead author Raed A. Joundi, MD, DPhil, McMaster University, Hamilton, Ontario, Canada, said in a press release.

“There is a need to accelerate the implementation of promising interventions or multipronged approaches into large randomized controlled trials to lower the risk of dementia,” the investigators wrote.
 

SOURCE:

The study was published online on December 4 in Neurology.

LIMITATIONS:

The study’s limitations included reliance on administrative coding without imaging data, potential underestimation of mild dementia, and lack of granular information on stroke severity, disability, and prestroke cognitive decline. While adjustments were made for healthcare contact and secondary prevention medications, residual biases may have persisted.

DISCLOSURES:

This study received funding from the Canada Brain Research Fund, Heart & Stroke Foundation of Canada, and Canadian Stroke Consortium. Two authors hold awards and positions from national organizations and academic institutions in Canada. Additional details are provided in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

TOPLINE:

Risk for dementia is nearly 80% higher in stroke survivors than in those without stroke, a new study reveals. The data suggest risk declines within 1 year after stroke but remains elevated for up to 20 years.

METHODOLOGY:

• Researchers conducted a population-wide analysis of over 15 million people in Canada between 2002 and 2022. The study focused on adults hospitalized for ischemic stroke, intracerebral hemorrhage, or acute myocardial infarction (AMI).
• Of 175,980 stroke survivors, 99% were matched 1:1 to residents without stroke on the basis of age, sex, rural residence, neighborhood deprivation, and vascular comorbidities. In addition, 90% of patients were matched to those with AMI.
• Incident dementia diagnoses were tracked starting 90 days after stroke until death, emigration, or the end of the study, using a validated algorithm based on hospitalization for dementia, prescriptions for cholinesterase inhibitors, or physician claims within 2 years.
• The mean follow-up duration was 5.6 years.

TAKEAWAY:

• Among stroke survivors, 19% were diagnosed with dementia vs 12.5% in the reference population. The dementia rate per 100 person-years was higher among stroke survivors than in the reference population over the entire follow-up period (3.34 vs 1.89).
• Over the entire study period, dementia was 76% more likely among stroke patients (hazard ratio [HR], 1.76; 95% CI, 1.73-1.79) and 82% more likely in the AMI cohort (HR, 1.82; 95% CI, 1.79-1.85) than in the reference population.
• Time-varying analysis revealed that dementia risk was highest within the first year after stroke, with a > 2.5-fold increase at 6 months (HR, 2.51; 95% CI, 2.42-2.59), which decreased to a 1.5-fold increase at 5 years (HR, 1.51; 95% CI, 1.48-1.56) but remained elevated compared with the reference population even 20 years after the index stroke.
• Recurrent stroke was associated with an approximately threefold increased risk for dementia (single recurrent stroke adjusted HR, 2.64; 95% CI, 2.54-2.74; multiple recurrent strokes adjusted HR, 3.05; 95% CI, 2.81-3.33).

IN PRACTICE:

“While much research has been focused on reducing the risk of a second stroke, our findings make it clear that more research also is needed on developing interventions to help prevent dementia after stroke,” lead author Raed A. Joundi, MD, DPhil, McMaster University, Hamilton, Ontario, Canada, said in a press release.

“There is a need to accelerate the implementation of promising interventions or multipronged approaches into large randomized controlled trials to lower the risk of dementia,” the investigators wrote.
 

SOURCE:

The study was published online on December 4 in Neurology.

LIMITATIONS:

The study’s limitations included reliance on administrative coding without imaging data, potential underestimation of mild dementia, and lack of granular information on stroke severity, disability, and prestroke cognitive decline. While adjustments were made for healthcare contact and secondary prevention medications, residual biases may have persisted.

DISCLOSURES:

This study received funding from the Canada Brain Research Fund, Heart & Stroke Foundation of Canada, and Canadian Stroke Consortium. Two authors hold awards and positions from national organizations and academic institutions in Canada. Additional details are provided in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.

Tina is a lovely 67-year-old woman who was recently found to be an APOE gene carrier (a gene associated with increased risk of developing Alzheimer’s disease as well as an earlier age of disease onset), with diffused amyloid protein deposition her brain. 

Her neuropsychiatric testing was consistent with mild cognitive impairment. Although Tina is not a doctor herself, her entire family consists of doctors, and she came to me under their advisement to consider semaglutide (Ozempic) for early Alzheimer’s disease prevention. 

This would usually be simple, but in Tina’s case, there was a complicating factor: At 5’ and 90 pounds, she was already considerably underweight and was at risk of becoming severely undernourished. 

To understand the potential role for glucagon-like peptide-1 (GLP-1) receptor agonists such as Ozempic in prevention, a quick primer on Alzheimer’s Disease is necessary.

The exact cause of Alzheimer’s disease remains elusive, but it is probably due to a combination of factors, including:

• Buildup of abnormal amyloid and tau proteins around brain cells
• Brain shrinkage, with subsequent damage to blood vessels and mitochondria, and inflammation
• Genetic predisposition
• Lifestyle factors, including obesity, high blood pressure, high cholesterol, and diabetes.

GLP-1 receptor agonists can cross the blood-brain barrier and bind to GLP-1 receptors expressed by neurons. Once in the brain, they can reduce inflammation and improve functioning of the neurons. In early rodent trials, GLP-1 receptor agonists led to reduced amyloid and tau aggregation, downregulation of inflammation, and improved memory.

In 2021, multiple studies showed that liraglutide, an early GLP-1 receptor agonist, improved cognitive function and MRI volume in patients with Alzheimer’s disease. 

A study recently published in Alzheimer’s & Dementia analyzed data from 1 million people with type 2 diabetes and no prior Alzheimer’s disease diagnosis. The authors compared Alzheimer’s disease occurrence in patients taking various diabetes medications, including insulin, metformin, and GLP-1 receptor agonists. The study found that participants taking semaglutide had up to a 70% reduction in Alzheimer’s risk. The results were consistent across gender, age, and weight.

Given the reassuring safety profile of GLP-1 receptor agonists and lack of other effective treatment or prophylaxis for Alzheimer’s disease, I agreed to start her on dulaglutide (Trulicity). My rationale was twofold:

1. In studies, dulaglutide has the highest uptake in the brain tissue at 68%. By contrast, there is virtually zero uptake in brain tissue for semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro/Zepbound). Because this class of drugs exert their effects in the brain tissue, I wanted to give her a GLP-1 receptor agonist with a high percent uptake.

2. Trulicity has a minimal effect on weight loss compared with the newer-generation GLP-1 receptor agonists. Even so, I connected Tina to my dietitian to ensure that she would receive a high-protein, high-calorie diet.

Tina has now been taking Trulicity for 6 months. Although it is certainly too early to draw firm conclusions about the efficacy of her treatment, she is not experiencing any weight loss and is cognitively stable, according to her neurologist. 

The EVOKE and EVOKE+ phase 3 trials are currently underway to evaluate the efficacy of semaglutide to treat mild cognitive impairment and early Alzheimer’s in amyloid-positive patients. Results are expected in 2025, but in the meantime, I feel comforted knowing that Tina is receiving a potentially beneficial and definitively low-risk treatment. 

 

Dr Messer, Clinical Assistant Professor, Mount Sinai School of Medicine; Associate Professor, Hofstra School of Medicine, New York, NY, has disclosed no relevant financial relationships.

A version of this article appeared on Medscape.com.

Tina is a lovely 67-year-old woman who was recently found to be an APOE gene carrier (a gene associated with increased risk of developing Alzheimer’s disease as well as an earlier age of disease onset), with diffused amyloid protein deposition her brain. 

Her neuropsychiatric testing was consistent with mild cognitive impairment. Although Tina is not a doctor herself, her entire family consists of doctors, and she came to me under their advisement to consider semaglutide (Ozempic) for early Alzheimer’s disease prevention. 

This would usually be simple, but in Tina’s case, there was a complicating factor: At 5’ and 90 pounds, she was already considerably underweight and was at risk of becoming severely undernourished. 

To understand the potential role for glucagon-like peptide-1 (GLP-1) receptor agonists such as Ozempic in prevention, a quick primer on Alzheimer’s Disease is necessary.

The exact cause of Alzheimer’s disease remains elusive, but it is probably due to a combination of factors, including:

• Buildup of abnormal amyloid and tau proteins around brain cells
• Brain shrinkage, with subsequent damage to blood vessels and mitochondria, and inflammation
• Genetic predisposition
• Lifestyle factors, including obesity, high blood pressure, high cholesterol, and diabetes.

GLP-1 receptor agonists can cross the blood-brain barrier and bind to GLP-1 receptors expressed by neurons. Once in the brain, they can reduce inflammation and improve functioning of the neurons. In early rodent trials, GLP-1 receptor agonists led to reduced amyloid and tau aggregation, downregulation of inflammation, and improved memory.

In 2021, multiple studies showed that liraglutide, an early GLP-1 receptor agonist, improved cognitive function and MRI volume in patients with Alzheimer’s disease. 

A study recently published in Alzheimer’s & Dementia analyzed data from 1 million people with type 2 diabetes and no prior Alzheimer’s disease diagnosis. The authors compared Alzheimer’s disease occurrence in patients taking various diabetes medications, including insulin, metformin, and GLP-1 receptor agonists. The study found that participants taking semaglutide had up to a 70% reduction in Alzheimer’s risk. The results were consistent across gender, age, and weight.

Given the reassuring safety profile of GLP-1 receptor agonists and lack of other effective treatment or prophylaxis for Alzheimer’s disease, I agreed to start her on dulaglutide (Trulicity). My rationale was twofold:

1. In studies, dulaglutide has the highest uptake in the brain tissue at 68%. By contrast, there is virtually zero uptake in brain tissue for semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro/Zepbound). Because this class of drugs exert their effects in the brain tissue, I wanted to give her a GLP-1 receptor agonist with a high percent uptake.

2. Trulicity has a minimal effect on weight loss compared with the newer-generation GLP-1 receptor agonists. Even so, I connected Tina to my dietitian to ensure that she would receive a high-protein, high-calorie diet.

Tina has now been taking Trulicity for 6 months. Although it is certainly too early to draw firm conclusions about the efficacy of her treatment, she is not experiencing any weight loss and is cognitively stable, according to her neurologist. 

The EVOKE and EVOKE+ phase 3 trials are currently underway to evaluate the efficacy of semaglutide to treat mild cognitive impairment and early Alzheimer’s in amyloid-positive patients. Results are expected in 2025, but in the meantime, I feel comforted knowing that Tina is receiving a potentially beneficial and definitively low-risk treatment. 

 

Dr Messer, Clinical Assistant Professor, Mount Sinai School of Medicine; Associate Professor, Hofstra School of Medicine, New York, NY, has disclosed no relevant financial relationships.

A version of this article appeared on Medscape.com.

Tina is a lovely 67-year-old woman who was recently found to be an APOE gene carrier (a gene associated with increased risk of developing Alzheimer’s disease as well as an earlier age of disease onset), with diffused amyloid protein deposition her brain. 

Her neuropsychiatric testing was consistent with mild cognitive impairment. Although Tina is not a doctor herself, her entire family consists of doctors, and she came to me under their advisement to consider semaglutide (Ozempic) for early Alzheimer’s disease prevention. 

This would usually be simple, but in Tina’s case, there was a complicating factor: At 5’ and 90 pounds, she was already considerably underweight and was at risk of becoming severely undernourished. 

To understand the potential role for glucagon-like peptide-1 (GLP-1) receptor agonists such as Ozempic in prevention, a quick primer on Alzheimer’s Disease is necessary.

The exact cause of Alzheimer’s disease remains elusive, but it is probably due to a combination of factors, including:

• Buildup of abnormal amyloid and tau proteins around brain cells
• Brain shrinkage, with subsequent damage to blood vessels and mitochondria, and inflammation
• Genetic predisposition
• Lifestyle factors, including obesity, high blood pressure, high cholesterol, and diabetes.

GLP-1 receptor agonists can cross the blood-brain barrier and bind to GLP-1 receptors expressed by neurons. Once in the brain, they can reduce inflammation and improve functioning of the neurons. In early rodent trials, GLP-1 receptor agonists led to reduced amyloid and tau aggregation, downregulation of inflammation, and improved memory.

In 2021, multiple studies showed that liraglutide, an early GLP-1 receptor agonist, improved cognitive function and MRI volume in patients with Alzheimer’s disease. 

A study recently published in Alzheimer’s & Dementia analyzed data from 1 million people with type 2 diabetes and no prior Alzheimer’s disease diagnosis. The authors compared Alzheimer’s disease occurrence in patients taking various diabetes medications, including insulin, metformin, and GLP-1 receptor agonists. The study found that participants taking semaglutide had up to a 70% reduction in Alzheimer’s risk. The results were consistent across gender, age, and weight.

Given the reassuring safety profile of GLP-1 receptor agonists and lack of other effective treatment or prophylaxis for Alzheimer’s disease, I agreed to start her on dulaglutide (Trulicity). My rationale was twofold:

1. In studies, dulaglutide has the highest uptake in the brain tissue at 68%. By contrast, there is virtually zero uptake in brain tissue for semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro/Zepbound). Because this class of drugs exert their effects in the brain tissue, I wanted to give her a GLP-1 receptor agonist with a high percent uptake.

2. Trulicity has a minimal effect on weight loss compared with the newer-generation GLP-1 receptor agonists. Even so, I connected Tina to my dietitian to ensure that she would receive a high-protein, high-calorie diet.

Tina has now been taking Trulicity for 6 months. Although it is certainly too early to draw firm conclusions about the efficacy of her treatment, she is not experiencing any weight loss and is cognitively stable, according to her neurologist. 

The EVOKE and EVOKE+ phase 3 trials are currently underway to evaluate the efficacy of semaglutide to treat mild cognitive impairment and early Alzheimer’s in amyloid-positive patients. Results are expected in 2025, but in the meantime, I feel comforted knowing that Tina is receiving a potentially beneficial and definitively low-risk treatment. 

 

Dr Messer, Clinical Assistant Professor, Mount Sinai School of Medicine; Associate Professor, Hofstra School of Medicine, New York, NY, has disclosed no relevant financial relationships.

A version of this article appeared on Medscape.com.