Brain reserve against physical disability progression over 5 years in multiple sclerosis

Brain reserve and timing of clinical onset in multiple sclerosis

BACKGROUND

A latent period of variable length elapses between multiple sclerosis (MS) biological onset and the occurrence of the first clinical episode reflecting a central nervous system (CNS) demyelinating event. Factors affecting the duration of such interval are unknown.

OBJECTIVE

To explore whether brain reserve, which moderates the impact of structural damage along MS course, could also affect the timing of MS clinical onset.

METHODS

We conducted a time-to-event analysis in 326 relapsing-onset multiple sclerosis patients to ascertain the effect of brain reserve, that is, larger maximal lifetime brain growth (MLBG) estimated as intracranial volume, on the risk of an earlier disease onset. For this purpose, we carried out a Cox proportional hazards regression model stratified by sex and adjusted by site and pre-morbid MS risk factors. All patients reached the event (i.e. the disease onset) with no censored case; the age (years) at disease onset was set as the main time variable.

RESULTS

We identified a protective effect of brain reserve on the time to disease onset (HR = 0.11, 95% CI = 0.02-0.83, p = 0.032), unchanged when accounting for MS risk factors.

CONCLUSION

Brain reserve might counteract the pathological mechanisms ongoing after biological initiation, thus delaying the disease overt clinical manifestation.

Towards new perspectives: A scoping review and meta-synthesis to redefine brain health for multiple sclerosis

BACKGROUND AND PURPOSE

Research promoting the health of the brain has increased exponentially over the last decade. The importance of 'brain health' for multiple sclerosis (MS), as one example, is a high priority. However, as research into the concept increases, so does varied use of the term.

METHODS

A scoping review, guided by the methodological framework of the Joanna Briggs Institute, was conducted to collate the evidence relating to brain health for MS. A comprehensive literature search incorporated six search strategies to retrieve both scientific and grey literature sources. All evidence sources were qualitatively charted and synthesized (meta-synthesis) according to their definition of brain health used, outcome measures and brain-healthy lifestyle elements.

RESULTS

Seventy evidence sources (34 peer reviewed, 36 grey literature) were eligible for inclusion. Of these, just over half (n = 40, 57%) provided a definition of brain health. The most common definition alluded to the biomedical model of neurological reserve (n = 22, 55%), a self-remodelling theory described to retain optimal brain function. Twenty-nine outcome measures of brain health were identified, the most frequent being magnetic resonance imaging metrics (n = 25, 83%). Physical activity was the most prevalent brain-healthy lifestyle element (n = 44), followed by avoidance of smoking (n = 26) and diet (n = 24).

CONCLUSIONS

Brain health should be considered a primary target for optimal disease and lifestyle management across the MS disease course. A working definition reflecting a shift from a medical lens towards broader biopsychosocial contexts that may influence brain health for people living with MS is proposed.

Defining the concept of reserve in the motor domain: a systematic review

A reserve in the motor domain may underlie the capacity exhibited by some patients to maintain motor functionality in the face of a certain level of disease. This form of "motor reserve" (MR) could include cortical, cerebellar, and muscular processes. However, a systematic definition has not been provided yet. Clarifying this concept in healthy individuals and patients would be crucial for implementing prevention strategies and rehabilitation protocols. Due to its wide application in the assessment of motor system functioning, non-invasive brain stimulation (NIBS) may support such definition. Here, studies focusing on reserve in the motor domain and studies using NIBS were revised. Current literature highlights the ability of the motor system to create a reserve and a possible role for NIBS. MR could include several mechanisms occurring in the brain, cerebellum, and muscles, and NIBS may support the understanding of such mechanisms.

Adaptation of the Concept of Brain Reserve for the Prediction of Stroke Outcome: Proxies, Neural Mechanisms, and Significance for Research

The prediction of stroke outcome is challenging due to the high inter-individual variability in stroke patients. We recently suggested the adaptation of the concept of brain reserve (BR) to improve the prediction of stroke outcome. This concept was initially developed alongside the one for the cognitive reserve for neurodegeneration and forms a valuable theoretical framework to capture high inter-individual variability in stroke patients. In the present work, we suggest and discuss (i) BR-proxies-quantitative brain characteristics at the time stroke occurs (e.g., brain volume, hippocampus volume), and (ii) proxies of brain pathology reducing BR (e.g., brain atrophy, severity of white matter hyperintensities), parameters easily available from a routine MRI examination that might improve the prediction of stroke outcome. Though the influence of these parameters on stroke outcome has been partly reported individually, their independent and combined impact is yet to be determined. Conceptually, BR is a continuous measure determining the amount of brain structure available to mitigate and compensate for stroke damage, thus reflecting individual differences in neural resources and a capacity to maintain performance and recover after stroke. We suggest that stroke outcome might be defined as an interaction between BR at the time stroke occurs and lesion load. BR in stroke can potentially be influenced, e.g., by modifying cardiovascular risk factors. In addition to the potential power of the BR concept in a mechanistic understanding of inter-individual variability in stroke outcome and establishing individualized therapeutic approaches, it might help to strengthen the synergy of preventive measures in stroke, neurodegeneration, and healthy aging.

Managing cognitive impairment and its impact in multiple sclerosis: An Australian multidisciplinary perspective

Cognitive impairment in multiple sclerosis (MS) affects approximately 40-70% of patients and can have varying degrees of severity. Even mild cognitive impairment can impact on quality of life and productivity. Despite this, patients are not routinely screened or monitored for cognitive impairment in Australia due to a range of issues, with time and space being the main limiting factors. This Australian multidisciplinary perspective provides recommendations on cognition management in Australia. It gives a broad overview of cognition in MS, advice on the screening and monitoring tools available to clinicians, and strategies that can be implemented in clinics to help monitor for cognitive impairment in patients with MS. We suggest a routine baseline assessment and multidomain cognitive battery in regular intervals; a change should trigger a thorough investigation of the cause.

Validation of a New Semiautomated Segmentation Pipeline Based on the Spinal Cord Toolbox DeepSeg Algorithm to Estimate the Cervical Canal Area

BACKGROUND AND PURPOSE

As in the brain reserve concept, a larger cervical canal area may also protect against disability. In this context, a semiautomated pipeline has been developed to obtain quantitative estimations of the cervical canal area. The aim of the study was to validate the pipeline, to evaluate the consistency of the cervical canal area measurements during a 1-year period, and to compare cervical canal area estimations obtained from brain and cervical MRI acquisitions.

MATERIALS AND METHODS

Eight healthy controls and 18 patients with MS underwent baseline and follow-up 3T brain and cervical spine sagittal 3D MPRAGE. The cervical canal area was measured in all acquisitions, and estimations obtained with the proposed pipeline were compared with manual segmentations performed by 1 evaluator using the Dice similarity coefficient. The cervical canal area estimations obtained on baseline and follow-up T1WI were compared; brain and cervical cord acquisitions were also compared using the individual and average intraclass correlation coefficients.

RESULTS

The agreement between the manual cervical canal area masks and the masks provided by the proposed pipeline was excellent, with a mean Dice similarity coefficient mean of 0.90 (range, 0.73-0.97). The cervical canal area estimations obtained from baseline and follow-up scans showed a good level of concordance (intraclass correlation coefficient = 0.76; 95% CI, 0.44-0.88); estimations obtained from brain and cervical MRIs also had good agreement (intraclass correlation coefficient = 0.77; 95% CI, 0.45-0.90).

CONCLUSIONS

The proposed pipeline is a reliable tool to estimate the cervical canal area. The cervical canal area is a stable measure across time; moreover, when cervical sequences are not available, the cervical canal area could be estimated using brain T1WI.

Exploring the relation between reserve and fatigue in multiple sclerosis

INTRODUCTION

Intellectual enrichment and brain reserve modulate the expression of cognitive and motor disability in multiple sclerosis (MS). Their association with fatigue, one of the most debilitating and common symptoms of MS, has never been explored.

MATERIALS AND METHODS

Forty-eight MS patients underwent clinical and MRI examination at baseline and after 1 year. Physical and cognitive MS-related fatigue were evaluated via Modified Fatigue Impact subscales (MFIS-P and MFIS-C). Differences in reserve indexes between fatigued and non-fatigued patients were tested. The relationship between clinico-demographic features, global brain structural damage, indexes of reserve (age-adjusted intracranial volume and cognitive reserve index) and fatigue were tested via correlations and hierarchical linear/binary logistic regression, to predict MFIS-P and MFIS-C (at baseline) or new-onset fatigue and meaningful worsening in MFIS (at follow-up).

RESULTS

At baseline, although a significant difference was identified for cognitive reserve questionnaire between fatigued and non-fatigued patients (18.19 ± 4.76 versus 15.15 ± 3.56, p = 0.015), only depression accounted for significant variance in MFIS-P and MFIS-C (R²=0.248, p = 0.002; R²=0.252, p<0.001). MFIS-T, MFIS-P and MFIS-C changes over time were associated to depression changes over time (r = 0.56, r = 0.55, and r = 0.57, respectively; all p<0.001). Indexes of reserve did not differ between non-fatigued patients and patients developing new-onset fatigue at follow-up. None of the baseline features was able to predict the new-onset fatigue or meaningful worsening in MFIS at follow-up.

CONCLUSIONS

Among the explored features, only depression was strongly associated to both physical and cognitive fatigue. Intellectual enrichment and brain reserve did not seem to affect fatigue symptoms in MS patients.

Spinal cord reserve in multiple sclerosis

BACKGROUND

The spinal cord (SC) is a preferential target of multiple sclerosis (MS) damage highly relevant towards disability. Differential impact of such damage could be due to the initial amount of SC tissue, as described for the brain parenchyma (brain reserve concept). We aimed to test the existence of SC reserve by using spinal canal area (SCaA) as a proxy.

METHODS

Brain sagittal three-dimensional T1-weighted scans covering down to C5 level were acquired in 2930 people with MS and 43 healthy controls (HCs) in a cross-sectional, multicentre study. SC area (SCA) and SCaA were obtained with the Spinal Cord Toolbox. Demographical data and patient-derived disability scores were obtained. SC parameters were compared between groups with age-adjusted and sex-adjusted linear regression models. The main outcome of the study, the existence of an association between SCaA and Patient Determined Disease Steps, was tested with scaled linear models.

RESULTS

1747 persons with MS (mean age: 46.35 years; 73.2% female) and 42 HCs (mean age: 45.56 years; 78.6% female) were analysed after exclusion of post-processing errors and application of quality criteria. SCA (60.41 mm² vs 65.02 mm², p<0.001) was lower in people with MS compared with HC; no differences in SCaA were observed (213.24 mm² vs 212.61 mm², p=0.125). Adjusted scaled linear models showed that a larger SCaA was significantly associated with lower scores on Patient Determined Disease Steps (beta coefficient: -0.12, p=0.0124) independently of spinal cord atrophy, brain T2 lesion volume, age and sex.

CONCLUSIONS

A larger SCaA may be protective against disability in MS, possibly supporting the existence of SC reserve.

Considering patient age when treating multiple sclerosis across the adult lifespan

Introduction: The successful development of anti-inflammatory disease-modifying treatments (DMT) significantly improved disease outcomes and longevity of persons with multiple sclerosis (pwMS). However, the shift toward an elderly MS population has resulted with new concerns regarding DMT efficacy and safety.Areas covered: This review summarizes the evidence of an age-based decrease in the efficacy of MS DMTs and increase in pharmacovigilance concerns. The age effects on pathophysiological MS processes, immunosenescence and its relevance to DMT selection or discontinuation are also reviewed. Lastly, the authors discuss the influence of age-associated comorbidities on DMT initiation and drug-induced events.Expert opinion: There is an age discrepancy between pwMS included in regulatory drug trials and an aging real-world MS population. Most trials demonstrate significantly diminished anti-inflammatory efficacy in patients older than 40 years old. Older age is associated with a greater risk for adverse events including serious infections. Age-associated comorbidities influence the risk-benefit analysis and sometimes cause patients to discontinue DMTs. Instead of chronological age cutoffs, therefore, studies should aim at promoting biologically-based age biomarkers.

Quantitative MRI phenotypes capture biological heterogeneity in multiple sclerosis patients

Magnetization transfer ratio (MTR) and brain volumetric imaging are (semi-)quantitative MRI markers capturing demyelination, axonal degeneration and/or inflammation. However, factors shaping variation in these traits are largely unknown. In this study, we collected a longitudinal cohort of 33 multiple sclerosis (MS) patients and extended it cross-sectionally to 213. We measured MTR in lesions, normal-appearing white matter (NAWM), normal-appearing grey matter (NAGM) and total brain, grey matter, white matter and lesion volume. We also calculated the polygenic MS risk score. Longitudinally, inter-patient differences at inclusion and intra-patient changes during follow-up together explained > 70% of variance in MRI, with inter-patient differences at inclusion being the predominant source of variance. Cross-sectionally, we observed a moderate correlation of MTR between NAGM and NAWM and, less pronounced, with lesions. Age and gender explained about 30% of variance in total brain and grey matter volume. However, they contributed less than 10% to variance in MTR measures. There were no significant associations between MRI traits and the genetic risk score. In conclusion, (semi-)quantitative MRI traits change with ongoing disease activity but this change is modest in comparison to pre-existing inter-patient differences. These traits reflect individual variation in biological processes, which appear different from those involved in genetic MS susceptibility.

Late onset multiple sclerosis is associated with more severe ventricle expansion

BACKGROUND

Late-onset multiple sclerosis (LOMS) is associated with faster disability progression than persons with adult-onset MS (PwAOMS). The differences in brain atrophy are currently unknown.

OBJECTIVES

To determine MRI-derived atrophy rates in persons with late-onset MS (PwLOMS) and compare them to an age-matched and disease duration-matched sample of PwAOMS.

METHODS

870 persons with MS (290 PwLOMS, 290 age-matched PwAOMS, and 290 disease duration-matched PwAOMS), and 150 healthy controls (HCs), were followed for 5 years and 3 years, respectively. Cross-sectional and longitudinal measures of T2-lesion volume (LV), lateral ventricular volume (LVV) and whole brain volume (WBV) were derived. Expanded Disability Status Scale (EDSS) and Multiple Sclerosis Severity Score (MSSS) were calculated. Both analyses were corrected for false discovery rate.

RESULTS

Persons with MS exhibited significantly greater annualized WBV loss (-0.88% vs. -0.38%, p<0.001) and annualized LVV expansion (3.1% vs. 1.7%, p=0.002) when compared to HCs. PwLOMS had significantly higher baseline and follow-up median MSSS when compared to both age-matched and disease duration-matched PwAOMS (p<0.026). PwLOMS showed significantly greater percent LVV change (14.3% vs. 9.3% p=0.001) and greater annualized percent LVV change (4.1% vs. 1.6%, p<0.001) compared to age-matched PwAOMS.

CONCLUSION

PwLOMS had higher MSSS and greater ventricle expansion when compared to PwAOMS.

Accelerated Trajectories of Walking Capacity Across the Adult Life Span in Persons With Multiple Sclerosis: An Underrecognized Challenge

Background. In the general population, trajectories of walking capacity is accelerated and nonlinear with advanced age. Whether this is more pronounced in persons with multiple sclerosis (pwMS), along with the prevalence of dismobility (ie, slow gait speed), are currently unknown. Our objective was to investigate trajectories of walking capacity and prevalence of dismobility across the adult life span in pwMS versus healthy controls (HC). Methods. Data on maximal timed 25-foot walk test (T25FWT), 2-minute walk test (2MWT), and 6-minute walk test (6MWT) along with prevalence of dismobility were assembled from 2 RIMS multicenter studies (n = 502 pwMS; age range 21-77 years, 6 age groups: 20-29, 30-39, 40-49, 50-59, 60-69, and 70-79 years). HC data were extracted from studies containing normative reference values (n = 1070-3780 HC). Results. Age trajectories of walking capacity was nonlinear and accelerated in pwMS versus HC. While measures of walking capacity in pwMS were suppressed already early in life, the gap between pwMS and HC significantly widened across the 6 age groups (pwMS performed 64%, 70%, 57%, 59%, 51%, and 37% of HC, respectively). This coincided with high prevalences of dismobility in pwMS across the 6 age groups when using usual gait speed cut-point values <1.0 m/s (corresponding to 33%, 32%, 51%, 59%, 75%, and 100%) and <0.6 m/s (corresponding to 19%, 12%, 26%, 23%, 33%, and 43%), markedly exceeding that observed in HC. Conclusion. The present data on walking capacity provide evidence for an accelerated deterioration in pwMS with advanced age, coinciding with high prevalences of dismobility (ie, slow gait speed).

Precision medicine in the multiple sclerosis clinic: Selecting the right patient for the right treatment

Multiple sclerosis (MS) is a chronic, inflammatory disease of the central nervous system (CNS), affecting patients of all ages, causing neurologic disability if inadequately treated. Some patients have a relatively benign disease course without significant disability after decades, while a more aggressive course ensues in others and disability progression occurs after only several years. Certain risk factors confer a higher chance of a patient having aggressive MS. Currently over 15 disease-modifying treatments (DMTs) are approved for MS with different efficacy and safety profiles. Deciding which DMT to use in a specific patient requires a careful analysis of a patient’s disease course for high-risk factors for early progression, consideration of the efficacy and safety profile for potential therapy, as well as understanding of a patient’s lifestyle and expectations. The integration of these factors is the art of precision medicine, a necessary practice in the treatment of patients with MS.

Beyond rehabilitation: A prevention model of reserve and brain maintenance in multiple sclerosis

Persons with multiple sclerosis (MS) experience cognitive and physical decline despite more effective disease-modifying therapies (DMTs), and symptomatic treatments currently have limited efficacy. The best treatment of MS disability may, therefore, be prevention of decline. Here, we present a working model of reserve and brain maintenance, with a focus on modifiable risk and protective factors. At disease onset, patients have varying degrees of reserve, broadly conceptualized as the dynamic availability of cerebral resources to support functional capacity. A clinical focus on prevention aims to minimize factors that deplete reserve (e.g. disease burden, comorbidities) and maximize factors that preserve reserve (e.g. DMTs, cardiovascular health). We review evidence for cardiovascular health, diet, and sleep as three potentially important modifiable factors that may modulate cerebral reserve generally, but also in disease-specific ways. We frame the brain as a limited capacity system in which inefficient usage of available cerebral capacity (reserve) leads to or exacerbates functional deficits, and we provide examples of factors that may lead to such inefficiency (e.g. poor mood, obesity, cognitive-motor dual-tasking). Finally, we discuss the challenges and responsibilities of MS neurologists and patients in pursuing comprehensive brain maintenance as a preventive approach.

Psychological resilience is linked to motor strength and gait endurance in early multiple sclerosis

BACKGROUND

Psychologically resilient persons persist despite obstacles and bounce back after adversity, leading to better outcomes in non-neurologic populations. It is unknown whether psychological resilience relates to objective functional outcomes in multiple sclerosis (MS).

OBJECTIVE

To determine whether psychological resilience explains differential objective cognitive and motor functioning in persons with early MS.

METHODS

Psychological resilience was assessed in 185 patients with early MS and 50 matched healthy controls with the Connors-Davidson Resilience Scale (CDRS-10). Subjects completed the MS Functional Composite (MSFC) and a comprehensive neurobehavioral evaluation. Correlations assessed links between CDRS-10 and MSFC, motor indices (Total, Fine Motor, Gross Motor), and cognitive indices (Total, Cognitive Efficiency, Memory).

RESULTS

Higher CDRS-10 among patients was linked to better MSFC and motor outcomes (but not cognition), with the most robust relationships for gross motor function (grip strength, gait endurance). Findings were independent of mood and fatigue. CDRS-10 was unrelated to MS disease burden. CDRS-10 was also specifically linked to motor outcomes in healthy controls.

CONCLUSION

Functional outcomes vary across persons with MS, even when disease burden and neurologic disability are low. These findings identify high psychological resilience as a non-disease-specific contributor to motor strength and endurance, which may explain differential outcomes across patients.

Navigating choice in multiple sclerosis management

Background

With the advent of modern immunotherapies for relapsing-remitting multiple sclerosis (RRMS) and the increasing amount of treatment options on the market, MS has evolved as a treatable disease. Yet, at the same time, new challenges for the treating neurologists arise.

Main body

This review article covers some of these challenges, including when and how to start treatment, treatment monitoring, and finally considerations on what the increasing choice in treatment options brings to disease management and longer-term planning. Among others, these important issues comprise pregnancy, treatment sequencing, switching or even stopping treatment.

Conclusion

The ultimate goal for navigating choices in RRMS management is to choose the right drug for the right patient at the right time Throughout the article, there is a strong focus on practical aspects and individual decision making in MS to meet the concept of personalized medicine.

The Relevance of Neuroimaging Findings to Physical Disability in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system and one of the leading causes of disability in young adults. While some patients with MS have a benign course in which they develop limited disability even after many years, other patients have a rapidly progressive course resulting in severe disability. However, the progression of the disease, particularly disability, is currently a predictable course with neuroimaging features to some extend. Magnetic resonance imaging (MRI) is not only the main diagnostic tool but also used to monitor response to therapies, thanks to its high sensitivity and ability to identify clinically silent lesions. This report presents a literature review which examines in detail the relationship between MRI findings and disability.

Functional Connectivity Alterations Reveal Complex Mechanisms Based on Clinical and Radiological Status in Mild Relapsing Remitting Multiple Sclerosis

Resting state functional MRI (rs-fMRI) has provided important insights into functional reorganization in subjects with Multiple Sclerosis (MS) at different stage of disease. In this cross-sectional study we first assessed, by means of rs-fMRI, the impact of overall T2 lesion load (T2LL) and MS severity score (MSSS) on resting state networks (RSNs) in 62 relapsing remitting MS (RRMS) patients with mild disability (MSSS < 3). Independent Component Analysis (ICA) followed by dual regression analysis confirmed functional connectivity (FC) alterations of many RSNs in RRMS subjects compared to healthy controls. The anterior default mode network (DMNa) and the superior precuneus network (PNsup) showed the largest areas of decreased FC, while the sensory motor networks area M1 (SMNm1) and the medial visual network (MVN) showed the largest areas of increased FC. In order to better understand the nature of these alterations as well as the mechanisms of functional alterations in MS we proposed a method, based on linear regression, that takes into account FC changes and their correlation with T2LL and MSSS. Depending on the sign of the correlation between FC and T2LL, and furthermore the sign of the correlation with MSSS, we suggested the following possible underlying mechanisms to interpret altered FC: (1) FC reduction driven by MS lesions, (2) "true" functional compensatory mechanism, (3a) functional compensation attempt, (3b) "false" functional compensation, (4a) neurodegeneration, (4b) pre-symptomatic condition (damage precedes MS clinical manifestation). Our data shows areas satisfying 4 of these 6 conditions (i.e., 1,2,3b,4b), supporting the suggestion that increased FC has a complex nature that may exceed the simplistic assumption of an underlying compensatory mechanism attempting to limit the brain damage caused by MS progression. Exploring differences between RRMS subjects with short disease duration (MS_short) and RRMS with similar disability but longer disease duration (MS_long), we found that MS_short and MS_long were characterized by clearly distinct pattern of FC, involving predominantly sensory and cognitive networks respectively. Overall, these results suggest that the analysis of FC alterations in multiple large-scale networks in relation to radiological (T2LL) and clinical (MSSS, disease duration) status may provide new insights into the pathophysiology of relapse onset MS evolution.

Cognition in multiple sclerosis: Between cognitive reserve and brain volume

BACKGROUND

Several correlations between cognitive impairment (CI), radiologic markers and cognitive reserve (CR) have been documented in MS.

OBIECTIVE

To evaluate correlation between CI and brain volume (BV) considering CR as possibile mitigating factor.

METHODS

195 relapsing MS patients underwent a neuropsychological assessment using BICAMS. BV was estimated using SIENAX to obtain normalized volume of brain (NBV), white matter (NWV), gray matter (NGV) and cortical gray matter (CGV). CR was estimated using a previously validated tool.

RESULTS

Pearson test showed a correlation between the symbol digit modality test (SDMT) score and NBV (r=0.38; p<0.000) NGV(r=0.31; p<0.000), CGV (r=0.35; p<0.000) and CRI score(r=0.42; p<0.000). Linear regression (dependent variable:SDMT) showed a relationship with CR scores (p=0.000) and NGV(p<0.000). A difference was detected between cognitive impaired and preserved patients regarding mean of NBV(p=0.002), NGV(p=0.007), CGV(p=0.002) and CR Scores (p=0.007). Anova showed a association between the presence of CI (dependent variable) and the interaction term CRIQ × CGV (p=0.004) whit adjustment for age and disability evaluated by EDSS.

CONCLUSIONS

Our study shows a correlation between cognition and BV, in particular gray matter volume. Cognitive reserve is also confirmed as an important element playing a role in the complex interaction to determine the cognitive functions in MS.

New Insights into Multiple Sclerosis Clinical Course from the Topographical Model and Functional Reserve

Clinical course in multiple sclerosis (MS) is difficult to predict on group and individual levels. We discuss the topographical model of MS as a new approach to characterizing the clinical course, with the potential to personalize disability progression based on each individual patient's pattern of disease burden (eg, lesion location) and reserve. The dynamic clinical threshold depicted in this visual model may help clinicians to educate patients about clinical phenotype and disease burden, and foster an understanding of the difference between relapses and pseudoexacerbations. There is an emphasis on building reserve against cognitive and physical decline, encouraging agency among patients.

Differential effects of aging on motor and cognitive functioning in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) patients are impaired in motor and cognitive performance, but the extent to which these deficits are magnified by aging is unknown. In one prior study, differences in cognitive processing speed between MS patients and healthy individuals were of similar magnitude across the lifespan. Here, we have improved on this work by expanding assessment to multiple cognitive domains and motor functioning.

OBJECTIVE

To determine whether the degree of cognitive and motor dysfunction in MS is magnified with increasing age.

METHODS

In all, 698 MS patients (aged 29-71 years) and 226 healthy controls (HCs; aged 18-72 years) completed neuroperformance tests covering ambulation, upper extremity function, information processing speed, and memory.

RESULTS

Linear regression models predicting cognitive and motor function revealed main effects of MS/HC diagnosis, age, and education across all measures. There was also an interaction between age and diagnosis on measures of motor function, but not on cognitive outcomes.

CONCLUSION

The progression of motor decline is amplified by aging in MS. However, the degree of cognitive impairment does not vary across the lifespan. Thus, evidence of accelerated cognitive impairment in older adults with MS may signal the presence of other age-related cognitive pathologies.

The topographical model of multiple sclerosis: A dynamic visualization of disease course

Relapses and progression contribute to multiple sclerosis (MS) disease course, but neither the relationship between them nor the spectrum of clinical heterogeneity has been fully characterized. A hypothesis-driven, biologically informed model could build on the clinical phenotypes to encompass the dynamic admixture of factors underlying MS disease course. In this medical hypothesis, we put forth a dynamic model of MS disease course that incorporates localization and other drivers of disability to propose a clinical manifestation framework that visualizes MS in a clinically individualized way. The topographical model encapsulates 5 factors (localization of relapses and causative lesions; relapse frequency, severity, and recovery; and progression rate), visualized utilizing dynamic 3-dimensional renderings. The central hypothesis is that, like symptom recrudescence in Uhthoff phenomenon and pseudoexacerbations, progression clinically recapitulates prior relapse symptoms and unmasks previously silent lesions, incrementally revealing underlying lesion topography. The model uses real-time simulation software to depict disease course archetypes and illuminate several well-described but poorly reconciled phenomena including the clinical/MRI paradox and prognostic significance of lesion location and burden on disease outcomes. Utilization of this model could allow for earlier and more clinically precise identification of progressive MS and predictive implications can be empirically tested.