Brain reserve and cognitive reserve protect against cognitive decline over 4.5 years in MS

Defining Cognitive Reserve and Implications for Cognitive Aging

PURPOSE OF REVIEW

The aim of this review is to summarize current conceptual models of cognitive reserve (CR) and related concepts and to discuss evidence for these concepts within the context of aging and Alzheimer's disease.

RECENT FINDINGS

Evidence to date supports the notion that higher levels of CR, as measured by proxy variables reflective of lifetime experiences, are associated with better cognitive performance, and with a reduced risk of incident mild cognitive impairment/dementia. However, the impact of CR on longitudinal cognitive trajectories is unclear and may be influenced by a number of factors. Although there is promising evidence that some proxy measures of CR may influence structural brain measures, more research is needed. The protective effects of CR may provide an important mechanism for preserving cognitive function and cognitive well-being with age, in part because it can be enhanced throughout the lifespan. However, more research on the mechanisms by which CR is protective is needed.

Trait Conscientiousness predicts rate of longitudinal SDMT decline in multiple sclerosis

BACKGROUND

Many people with multiple sclerosis (MS) exhibit cognitive decline over several years. Baseline differences may put people at greater risk for such decline.

OBJECTIVE

To characterize rates of longitudinal cognitive decline and investigate baseline clinical predictors.

METHODS

We report a retrospective analysis of 531 MS patients whose data were gleaned from a multi-study database, aggregated over 16 years. Linear mixed effects modeling was applied to estimate the average rate of decline on Symbol Digit Modalities Test (SDMT) performance and to predict rates of decline using baseline clinical variables.

RESULTS

Participants exhibited an average estimated decline of 0.22 SDMT raw-score points/year (95% confidence interval (CI) (-0.32, -0.12)). We observed a significant main effect of time from baseline (t = -2.78, p = 0.006), test form (t = 2.13, p = 0.034), disease course (t = 2.91, p = 0.004), age (t = -2.76, p = 0.006), sex (t = -2.71, p = 0.007), subjective cognitive impairment (t = -2.00, p = 0.046), premorbid verbal intelligence (t = 5.14, p < 0.001), and trait Conscientiousness (t = 2.69, p = 0.008). A significant interaction emerged for Conscientiousness and time from baseline (t = 2.57, p = 0.011).

CONCLUSION

Higher baseline trait Conscientiousness predicts slower rates of longitudinal cognitive decline in MS. This relationship, the average rate of decline, and practice effects can inform future research and clinical treatment decisions.

Learning ability correlates with brain atrophy and disability progression in RRMS

OBJECTIVE

To assess the prognostic value of practice effect on Paced Auditory Serial Addition Test (PASAT) in multiple sclerosis.

METHODS

We compared screening (day -14) and baseline (day 0) PASAT scores of 1009 patients from the FTY720 Research Evaluating Effects of Daily Oral therapy in Multiple Sclerosis (FREEDOMS) trial. We grouped patients into high and low learners if their PASAT score change was above or below the median change in their screening PASAT quartile group. We used Wilcoxon test to compare baseline disease characteristics between high and low learners, and multiple regression models to assess the respective impact of learning ability, baseline normalised brain volume and treatment on brain volume loss and 6-month confirmed disability progression over 2 years.

RESULTS

The mean PASAT score at screening was 45.38, increasing on average by 3.18 from day -14 to day 0. High learners were younger (p=0.003), had lower Expanded Disability Status Scale score (p=0.031), higher brain volume (p<0.001) and lower T2 lesion volume (p=0.009) at baseline. Learning status was not significantly associated with disability progression (HR=0.953, p=0.779), when adjusting for baseline normalised brain volume, screening PASAT score and treatment arm. However, the effect of fingolimod on disability progression was more pronounced in high learners (HR=0.396, p<0.001) than in low learners (HR=0.798, p=0.351; p for interaction=0.05). Brain volume loss at month 24 tended to be higher in low learners (0.17%, p=0.058), after adjusting for the same covariates.

CONCLUSIONS

Short-term practice effects on PASAT are related to brain volume, disease severity and age and have clinically meaningful prognostic implications. High learners benefited more from fingolimod treatment.

The topographical model of MS: Empirical evaluation of the recapitulation hypothesis

OBJECTIVE

Using the topographical model of multiple sclerosis (MS) to evaluate a longitudinal cohort we (1) test the recapitulation hypothesis, positing that patients' "disease topography" predicts the clinical pattern of disability accumulation; and (2) identify leading indicators of progression.

METHODS

10 patients who transitioned from relapsing-remitting MS to secondary progressive MS (SPMS) were evaluated. Neurologic exams were analyzed from relapses, at time of SPMS diagnosis, and most recent visit. Functional systems (FS), location/laterality, and recovery were recorded. The pyramidal/motor system was the target FS assessing symptom laterality and severity at relapse and SPMS time-points. Each patient's clinical course was mapped using the topographical model software.

RESULTS

Cohort was 80% female, age 31.6 ± 8.6 years at diagnosis, followed average 23.8 ± 8.8 years, mean 3.1 relapses before SPMS. 83.3 ± 0.2% of relapse symptoms were present at transition to SPMS, increasing to 91.0 ± 0.2% at most recent visit. This demonstrates concordance between the topographical distribution of relapse symptoms and deficits from subsequent progression. In the topographical model, progression became apparent 7.75 years earlier than SPMS was diagnosed in practice.

CONCLUSIONS

We demonstrate the model's utility in depicting patients' disease topography as the loci of clinical progression. This could allow for earlier recognition of progressive disease by identifying leading indicators of progression.

Effective Reserve: A Latent Variable to Improve Outcome Prediction in Stroke

Prediction of functional outcome after stroke based on initial presentation remains an open challenge, suggesting that an important aspect is missing from these prediction models. There exists the notion of a protective mechanism called brain reserve, which may be utilized to understand variations in disease outcome. In this work, we expand the concept of brain reserve (effective reserve) to improve prediction models of functional outcome after acute ischemic stroke (AIS). Consecutive AIS patients with acute brain magnetic resonance imaging (<48 hours) were eligible for this study. White matter hyperintensity and acute infarct volume were determined on T2 fluid attenuated inversion recovery and diffusion weighted images, respectively. Modified Rankin Scale scores were obtained at 90days poststroke. Effective reserve was defined as a latent variable using structural equation modeling by including age, systolic blood pressure, and intracranial volume measurements. Of 453 AIS patients (mean age 66.6 ± 14.7 years), 36% were male and 311 hypertensive. There was inverse association between effective reserve and 90-day modified Rankin Scale scores (path coefficient -0.18 ± 0.01, P < .01). Compared to a model without effective reserve, correlation between predicted and observed modified Rankin Scale scores improved in the effective-reserve-based model (Spearman's ρ 0.29 ± 0.18 versus 0.15 ± 0.17, P < .001). Furthermore, hypertensive patients exhibited lower effective reserve (P < 10^-6). Using effective reserve in prediction models of stroke outcome is feasible and leads to better model performance. Furthermore, higher effective reserve is associated with more favorable functional poststoke outcome and might correspond to an overall better vascular health.

Longitudinal Stability of Cognition in Early-Phase Relapsing-Remitting Multiple Sclerosis: Does Cognitive Reserve Play a Role?

Background

Up to 70% of people with multiple sclerosis (MS) experience cognitive impairment. Some remain cognitively intact despite advanced disease. Cognitive reserve (CR) theory postulates that individuals with higher levels of intellectual enrichment can tolerate more pathology than others before exhibiting cognitive impairment.

Methods

Thirty-two individuals with early-phase relapsing-remitting MS with mild physical disability and disease duration less than 10 years and 32 controls were recruited. At baseline and after 3 years, participants completed neuropsychological tests evaluating several cognitive domains. The CR was assessed via a cognitive reserve index (CRI) using educational levels and North American Adult Reading Test scores. Change in cognition was assessed using a reliable change index.

Results

At baseline, people with MS performed worse than controls on visual memory. There were no significant group differences on information processing speed, learning, language, and executive functions. Most cognitive domains showed no change over time, and CRI was not a significant predictor in the regression model.

Conclusions

People with MS performed worse on memory tasks at baseline compared with controls. Cognitive change differed between people with MS and controls in executive functions. Although people with MS and controls improved over time, beyond practice effects, people with MS improved less than controls. Overall, no cognitive deterioration was noted over time, and CR did not predict change in cognition. Sample homogeneity in terms of disease stage and CR may explain these findings.

Effects of Cognitive Reserve on Cognitive Performance in a Follow-Up Study in Older Adults With Subjective Cognitive Complaints. The Role of Working Memory

Objective: Analyze the effects of CR on cognitive performance in adults with subjective cognitive complaints at follow-up. Method: We analyzed the factorial structure of the three constructs defined in cognitive performance (Episodic memory, Working memory, and General cognitive performance) separately to search for evidence of the invariance of the measurement model. We then developed four structural nested models to analyze the relationship between CR and cognitive performance, measured at baseline and after approximately 18 months, in 266 participants older than 50 years with subjective cognitive complaints. Results: The nested models revealed the following main results: direct effects of CR on all cognitive constructs at baseline and also indirect effects on the same constructs at follow-up, and indirect effects of CR on other cognitive constructs at follow-up via working memory at follow-up. Conclusion: The findings show that the proposed model is useful for measuring the influence of CR on cognitive performance in follow-up studies and that CR has a positive influence on cognitive performance at follow-up via working memory. CR may enhance mechanisms of information processing, favoring performance of tasks involving other cognitive constructs in older adults with subjective cognitive complaints.

Into the Moment: Does Mindfulness Affect Biological Pathways in Multiple Sclerosis?

Mindfulness was introduced in the Western world by Jon Kabat-Zinn in 1979. He defined it as "awareness that arises through paying attention, on purpose, in the present moment, non-judgmentally." Since then, research on mindfulness-based interventions (MBIs) has increased exponentially both in health and disease, including in patients with neurodegenerative diseases such as dementia and Parkinson's disease. Research on the effect of mindfulness and multiple sclerosis (MS) only recently gained interest. Several studies completed since 2010 provided evidence that mindfulness improves quality of life (QoL), depression and fatigue in MS patients. In addition to patient-reported outcome measures, potential effects on cognitive function have been investigated only to a very limited extent. However, research on laboratory biomarkers and neuroimaging, capable to deliver proof-of-concept of this behavioral treatment in MS, is mainly lacking. In this perspective, we illustrate possible neurobiological mechanisms, including the tripartite interaction between the brain, the immune system and neuroendocrine regulation, through which this treatment might affect multiple sclerosis symptoms. We propose to (1) include immunological and/or neuroimaging biomarkers as standard outcome measures in future research dedicated to mindfulness and MS to help explain the clinical improvements seen in fatigue and depression; (2) to investigate effects on enhancing cognitive reserve and cognitive function; and (3) to investigate the effects of mindfulness on the disease course in MS.

A simple measure of cognitive reserve is relevant for cognitive performance in MS patients

Cognitive reserve (CR) contributes to preserve cognition despite brain damage. This theory has been applied to multiple sclerosis (MS) to explain the partial relationship between cognition and MRI markers of brain pathology. Our aim was to determine the relationship between two measures of CR and cognition in MS. One hundred and forty-seven MS patients were enrolled. Cognition was assessed using the Rao's Brief Repeatable Battery and the Stroop Test. CR was measured as the vocabulary subtest of the WAIS-R score (VOC) and the number of years of formal education (EDU). Regression analysis included raw score data on each neuropsychological (NP) test as dependent variables and demographic/clinical parameters, VOC, and EDU as independent predictors. A binary logistic regression analysis including clinical/CR parameters as covariates and absence/presence of cognitive deficits as dependent variables was performed too. VOC, but not EDU, was strongly correlated with performances at all ten NP tests. EDU was correlated with executive performances. The binary logistic regression showed that only the Expanded Disability Status Scale (EDSS) and VOC were independently correlated with the presence/absence of CD. The lower the VOC and/or the higher the EDSS, the higher the frequency of CD. In conclusion, our study supports the relevance of CR in subtending cognitive performances and the presence of CD in MS patients.

White matter tract network disruption explains reduced conscientiousness in multiple sclerosis

Quantifying white matter (WM) tract disruption in people with multiple sclerosis (PwMS) provides a novel means for investigating the relationship between defective network connectivity and clinical markers. PwMS exhibit perturbations in personality, where decreased Conscientiousness is particularly prominent. This trait deficit influences disease trajectory and functional outcomes such as work capacity. We aimed to identify patterns of WM tract disruption related to decreased Conscientiousness in PwMS. Personality assessment and brain MRI were obtained in 133 PwMS and 49 age- and sex-matched healthy controls (HC). Lesion maps were applied to determine the severity of WM tract disruption between pairs of gray matter regions. Next, the Network-Based-Statistics tool was applied to identify structural networks whose disruption negatively correlates with Conscientiousness. Finally, to determine whether these networks explain unique variance above conventional MRI measures and cognition, regression models were applied controlling for age, sex, brain volume, T2-lesion volume, and cognition. Relative to HCs, PwMS exhibited lower Conscientiousness and slowed cognitive processing speed (p = .025, p = .006). Lower Conscientiousness in PwMS was significantly associated with WM tract disruption between frontal, frontal-parietal, and frontal-cingulate pathways in the left (p = .02) and right (p = .01) hemisphere. The mean disruption of these pathways explained unique additive variance in Conscientiousness, after accounting for conventional MRI markers of pathology and cognition (ΔR²  = .049, p = .029). Damage to WM tracts between frontal, frontal-parietal, and frontal-cingulate cortical regions is significantly correlated with reduced Conscientiousness in PwMS. Tract disruption within these networks explains decreased Conscientiousness observed in PwMS as compared with HCs.

Evaluating Cognitive Reserve Through the Prism of Preclinical Alzheimer Disease

The concept of cognitive reserve (CR) was proposed to account for the discrepancy between levels of brain pathologic features or damage and clinical and cognitive function. This article provides a detailed review of prospective longitudinal studies that have investigated the interaction between CR and Alzheimer's disease (AD) biomarkers on clinical and cognitive outcomes among individuals with preclinical AD. Current evidence shows that higher levels of CR are associated with a delay in the onset of symptoms of mild cognitive impairment and that there may be multiple pathways by which CR exerts its protective effects.

Face-to-Face or Telematic Cognitive Stimulation in Patients with Multiple Sclerosis and Cognitive Impairment: Why Not Both?

Introduction

Cognitive impairment (CI) affects 40-65% of patients with multiple sclerosis (MS). Few studies address telematic cognitive stimulation (TCS) in MS. The objective of this study is to evaluate the efficacy and impact of telestimulation or distance cognitive stimulation (TCS), with and without the support of face-to-face cognitive stimulation (FCS) in cognitive impairment in MS.

Methods

Multicentre, prospective, randomised, controlled study. We will include 98 MS patients with EDSS ≤ 6, symbol digit modality test (SDMT) ≤ Pc 25, and Multiple Sclerosis Neuropsychological Screening Questionnaire (MSNQ) > 26 points. Patients will be randomised into 3 groups, a TCS group, a mixed TCS/FCS group, and a control group. CS is performed 3 days a week for 3 months. Processing speed, memory, attention, and executive functions will be rehabilitated. FCS will include ecological exercises and strategies. EDSS and a cognitive evaluation (SDMT, CTMT, PASAT, and TAVEC), MSNQ, psychological impact scales (MSIS), and depression (BDI) will be carried out, baseline, postrehabilitation, and also 6 and 12 months later, to evaluate the effect of CS in the longer term.

Conclusion

This study could help to establish the usefulness of TCS or, in its absence, TCS with face-to-face help for CI in MS. The interest lies in the clear benefits of remote rehabilitation in the daily life of patients.

Cognition in multiple sclerosis: State of the field and priorities for the future

Cognitive decline is recognized as a prevalent and debilitating symptom of multiple sclerosis (MS), especially deficits in episodic memory and processing speed. The field aims to (1) incorporate cognitive assessment into standard clinical care and clinical trials, (2) utilize state-of-the-art neuroimaging to more thoroughly understand neural bases of cognitive deficits, and (3) develop effective, evidence-based, clinically feasible interventions to prevent or treat cognitive dysfunction, which are lacking. There are obstacles to these goals. Our group of MS researchers and clinicians with varied expertise took stock of the current state of the field, and we identify several important practical and theoretical challenges, including key knowledge gaps and methodologic limitations related to (1) understanding and measurement of cognitive deficits, (2) neuroimaging of neural bases and correlates of deficits, and (3) development of effective treatments. This is not a comprehensive review of the extensive literature, but instead a statement of guidelines and priorities for the field. For instance, we provide recommendations for improving the scientific basis and methodologic rigor for cognitive rehabilitation research. Toward this end, we call for multidisciplinary collaborations toward development of biologically based theoretical models of cognition capable of empirical validation and evidence-based refinement, providing the scientific context for effective treatment discovery.

Cognitive reserve, cognition, and regional brain damage in MS: A 2 -year longitudinal study

BACKGROUND

According to the cognitive reserve (CR) theory, enriching experiences protect against cognitive decline.

OBJECTIVES

To investigate the dynamic interaction between CR and global/regional measures of brain white matter (WM) and gray matter (GM) damage and their effect on cognitive performance in multiple sclerosis (MS).

METHODS

Baseline and 2 -year three-dimensional (3D) T1-weighted scans were obtained from 54 MS patients and 20 healthy controls. Patients' cognitive functions were tested and a cognitive reserve index (CRI) was calculated. Baseline regional atrophy and longitudinal volume changes were investigated using voxel-wise methods. Structural damage and CRI effects on cognitive performance were explored with linear models.

RESULTS

At baseline, MS patients showed atrophy of the deep GM nuclei, GM/WM frontal-temporal-parietal-occipital regions, and left cerebellum. Controlling for atrophy, higher CRI explained significant portions of variance in verbal memory and verbal fluency (∆ R² = 0.07-0.16; p < 0.03). The interaction between thalamic volume and CRI was significant (∆ R² = 0.05; p = 0.03). Longitudinal changes in memory and attention performance were associated with local/global variations of GM/WM and T2 lesions. CRI had no effect on longitudinal cognitive changes.

CONCLUSION

In MS, CR may have a protective role in preserving cognitive functions, moderating the effect of structural damage on cognitive performance. This protective role may diminish with disease progression.

The Relationship between Cognitive Reserve and Math Abilities

Cognitive Reserve is the capital of knowledge and experiences that an individual acquires over their life-span. Cognitive Reserve is strictly related to Brain Reserve, which is the ability of the brain to cope with damage. These two concepts could explain many phenomena such as the modality of onset in dementia or the different degree of impairment in cognitive abilities in aging. The aim of this study is to verify the effect of Cognitive Reserve, as measured by a questionnaire, on a variety of numerical abilities (number comprehension, reading and writing numbers, rules and principles, mental calculations and written calculations), in a group of healthy older people (aged 65–98 years). Sixty older individuals were interviewed with the Cognitive Reserve Index questionnaire (CRIq), and assessed with the Numerical Activities of Daily Living battery (NADL), which included formal tasks on math abilities, an informal test on math, one interview with the participant, and one interview with a relative on the perceived math abilities. We also took into account the years of education, as another proxy for Cognitive Reserve. In the multiple regression analyses on all formal tests, CRIq scores did not significantly predict math performance. Other variables, i.e., years of education and Mini-Mental State Examination score, accounted better for math performance on NADL. Only a subsection of CRIq, CRIq-Working-activity, was found to predict performance on a NADL subtest assessing informal use of math in daily life. These results show that education might better explain abstract math functions in late life than other aspects related to Cognitive Reserve, such as lifestyle or occupational attainment.

Functional Components of Cognitive Impairment in Multiple Sclerosis: A Cross-Sectional Investigation

Background

Cognitive impairment is frequent and disabling in multiple sclerosis (MS). Changes in information processing speed constitute the most important cognitive deficit in MS. However, given the clinical and topographical variability of the disease, cognitive impairment may vary greatly and appear in other forms in addition to slower information processing speed. Our aim was to determine the frequency of cognitive impairment, the principal cognitive domains, and components involved in MS and to identify factors associated with presence of cognitive impairment in these patients in a large series of patients.

Methods

Cross-sectional study of 311 patients with MS [236 with relapsing-remitting MS (RRMS), 52 with secondary progressive MS (SPMS), and 23 with primary progressive MS (PPMS)]. Patients' cognitive function was assessed with a comprehensive neuropsychological assessment protocol. Patients displaying deficits in 2 or more cognitive domains were considered to have cognitive impairment associated with MS. We conducted a principal component analysis to detect different cognitive patterns by identifying clusters of tests highly correlated to one another.

Results

Cognitive impairment was detected in 41.5% of the sample, and it was more frequent in patients with SPMS and PPMS (P = 0.002). Expanded Disability Status Scale scores and education were independent predictors of cognitive impairment. Principal component analysis identified seven clusters: attention and basic executive function (including information processing speed), planning and high-level executive function, verbal memory and language, executive and visuospatial performance time, fatigue-depression, visuospatial function, and basic attention and verbal/visual working memory. Mean scoring of components 2 (high-order executive functioning) and 3 (verbal memory-language) was higher in patients with RRMS than in those with PPMS (component 2) and SPMS (component 3).

Conclusion

MS is linked to multiple cognitive profiles and disturbances in different domains. This suggests that cognitive alterations in MS are heterogeneous and affect other domains in addition to information processing speed.

Anti-cholinergic medications for bladder dysfunction worsen cognition in persons with multiple sclerosis

Bladder dysfunction is common in persons with MS (PwMS), often due to detrusor muscle overactivity. Anticholinergic medications are considered the first line treatment for bladder dysfunction and are known to worsen cognition in healthy older adults and in persons with dementia. Yet, it is not known if these medications have the same effect on PwMS. Thus, the Objective of this prospective matched-cohort study was to determine if anticholinergic medications affect objective measures of cognition in PwMS. We recruited PwMS starting either oxybutynin or tolterodine (cases). Cases and controls were tested with the Brief International Cognitive Assessment for MS (BiCAMS) battery prior to starting anticholinergic medications and 12weeks later. The primary outcome was change on the Symbol Digit Modalities Test (SDMT) between groups; secondary outcomes were changes on the other BiCAMS measures. Analysis of Covariance with baseline measures as covariates to assess the significance of between group differences was performed at 12weeks. Forty eight PwMS starting anticholinergic medications and 21 matched PwMS controls were recruited. There was a significant difference (p<0.001) in the change on the cognitive measures over 12weeks between groups. The controls demonstrated improvement, consistent with practice effect, while the cases remained unchanged. This study demonstrates that anticholinergic medications may have a negative effect on cognition in PwMS; further confirmatory studies are needed.

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.

Pattern separation performance is decreased in patients with early multiple sclerosis

BACKGROUND

Hippocampal-dependent memory impairment is frequent and occurs early during the course of multiple sclerosis (MS). While mechanisms responsible for episodic memory dysfunction in patients with MS remain largely unknown, dentate gyrus structure has been suggested as particularly vulnerable at the early stage of the disease. If true, we hypothesized that the pattern separation component of episodic memory (a function known to be critically dependent to dentate gyrus function) would be impaired in patients with early MS (PweMS).

METHODS

Thirty eight participants (19 PweMS and 19 healthy controls matched on age, gender and education level) were tested with a behavioral pattern separation task and also for information processing speed and visuospatial episodic memory.

RESULTS

We report a significant decrease in pattern separation performance in PweMS compared to healthy controls (27.07 vs. 40.01, p = .030 after Holm-Bonferroni correction, d = 1.02) together with a significantly higher pattern completion rate (56.11 vs. 40.95, p = .004 after Holm-Bonferroni correction, d = 1.07) while no difference was found among groups for information processing speed and "global" visuospatial episodic memory regarding learning, long-term recall or recognition.

CONCLUSION

Our results suggest that behavioral pattern separation task can detect subtle memory decline in patients with MS and argue for early dentate gyrus dysfunction during the course of the disease.

Unprovoked seizures in multiple sclerosis: Why are they rare?

INTRODUCTION

The frequency of seizures in patients with multiple sclerosis (MS) ranges from 1.5% to 7.8% and is considerably more common than chance events. The etiopathogenesis of seizures in MS is still poorly understood.

METHOD

A review of the literature on seizures and MS using PubMed.

RESULTS

Cortical gray matter involvement appears to be an all-too-common pathological finding in MS to play a primary role in the pathogenesis of seizures in MS patients. There is no clear relationship between seizures and the severity of MS. In approximately 10% of cases, a seizure is actually an initial neurological symptom of MS.

CONCLUSION

Searching for coherence in the occurrence of unprovoked seizures in MS directs attention to the dichotomy in MS pathology characterized by a complex intertwining of neuroinflammatory and neurodegenerative processes. The appearance (or nonappearance) of seizures in MS in relation to disease activity and disease progression indicates a distinct clinical phenotype of MS that opens up new perspectives in MS research.

Prevalence of cognitive impairment among Hungarian patients with relapsing-remitting multiple sclerosis and clinically isolated syndrome

BACKGROUND

Cognitive impairment (CI) is a frequent symptom of multiple sclerosis (MS); its prevalence is reported to be 43-70%. It is one of the most important determinants of MS patients' quality of life, as it is one of the main factors for MS patients becoming unemployed.

AIM

We aimed to determine the prevalence of CI among the relapsing-remitting MS (RRMS) and clinically isolated syndrome (CIS) patients in Hungary, to evaluate the predicting factors of CI and to assess the differences between sexes and patients with different educational levels.

PATIENTS AND METHODS

Five-hundred and fifty-three CIS and RRMS patients were enrolled to our study from three Hungarian MS centers. Age at screening, age at disease onset, disease duration, EDSS score, sex and educational levels were analyzed as socio-demographic factors. The BICAMS battery was used to assess their cognitive state, the BDI-II battery to assess depression. For statistical analysis, we utilized logistical regression, and used Fisher exact tests, chi-square tests and one-way ANOVA.

RESULTS

The mean age of our patients was 44.93 ± 11.69 years, mean age at disease onset was 31.95 ± 10.01 years, the mean disease duration was 13.05 ± 8.05 years and the median EDSS score 2.0 (Range: 6.5, IQR:2.0) points. Three-hundred and sixteen (57.1%) patients had CI. Sex, educational level and EDSS score proved to be significant predictors of CI (OR: 2.71, p < 0.001; OR: 1.94, p = 0.023; OR: 0.47, p = 0.003 respectively). CI was significantly (p < 0.001) more frequent among men (70.1%) than women (52.0%). We found, that educational level and EDSS score were only a significant predicting factor among women. Thus, the prevalence of CI among women with college or university degree was significantly (p < 0.001) less common (39.4%) than women with 12-15 years of education (57.4%) and women without a high school degree (66.7%). Also, we found that among women with higher EDSS score than 2 points, the prevalence of CI is 69.9% as compared to women with EDSS score between 0 and 2 points, where the prevalence is 42.8% (p < 0.001). No such differences were observed among man.

DISCUSSION

Our prevalence data is similar to those reported in the literature (43-70%), and almost identical to the one assessment using the BICAMS battery. We found that men are more vulnerable to CI than women in MS, as was reported recently. We are the first to report however, that higher educational level and lower EDSS scores are only associated with better cognitive performance in women.

Cognitive reserve and cognitive performance of patients with focal frontal lesions

The Cognitive reserve (CR) hypothesis was put forward to account for the variability in cognitive performance of patients with similar degrees of brain pathology. Compensatory neural activity within the frontal lobes has often been associated with CR. For the first time we investigated the independent effects of two CR proxies, education and NART IQ, on measures of executive function, fluid intelligence, speed of information processing, verbal short term memory (vSTM), naming, and perception in a sample of 86 patients with focal, unilateral frontal lesions and 142 healthy controls. We fitted multiple linear regression models for each of the cognitive measures and found that only NART IQ predicted executive and naming performance. Neither education nor NART IQ predicted performance on fluid intelligence, processing speed, vSTM or perceptual abilities. Education and NART IQ did not modify the effect of lesion severity on cognitive impairment. We also found that age significantly predicted performance on executive tests and the majority of our other cognitive measures, except vSTM and GNT. Age was the only predictor for fluid intelligence. This latter finding suggests that age plays a role in executive performance over and above the contribution of CR proxies in patients with focal frontal lesions. Overall, our results suggest that the CR proxies do not appear to modify the relationship between cognitive impairment and frontal lesions.

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Effect of cognitive reserve (CR) proxies in focal unilateral lesions.

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NART IQ accounts for a larger proportion of variance in executive and naming skills.

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Age predicts performance on executive, fluid intelligence, speed and perception tests.

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Education and NART IQ did not modify the effect of lesion severity on cognitive impairment.

Contribution of Gray and White Matter Abnormalities to Cognitive Impairment in Multiple Sclerosis

Patients with multiple sclerosis (MS) commonly exhibit cognitive impairments (CI). However, the neural mechanisms underlying CI remain unclear. The current study applied diffusion tensor imaging (DTI) and voxel-based morphometric (VBM) magnetic resonance imaging (MRI) techniques to evaluate differences in white matter (WM) integrity and gray matter (GM) volume between MS patients with CI and MS patients with cognitive preservation (CP). Neuropsychological assessment and MRI were obtained from 39 relapsing-remitting MS (RRMS) patients and 29 healthy controls (HCs). Patients were classified as CI or CP according to cognitive ability, and demographic characteristics and MRI images were compared. Compared with HCs, MS patients exhibited widespread damage in WM integrity, and GM loss in several regions. Compared with CP patients, CI patients exhibited more extensive WM impairments, particularly in the corpus callosum, cerebellar peduncle, corona radiata, optic radiation, superior longitudinal fasciculus, anterior limb of the internal capsule, and cingulate, as well as decreased GM volume in the bilateral caudate, left insula and right temporal lobe. MS patients with CI exhibited more significant structural abnormalities than those with CP. Widespread impairments of WM integrity and selective GM atrophy both appear to be associated with impaired cognition in RRMS.

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 relevance of cortical lesions in patients with multiple sclerosis

BACKGROUND

Recent studies suggest that cortical lesions in multiple sclerosis (MS) substantially contribute to clinical disease severity. The present study aimed at investigating clinical, neuroanatomical, and cognitive correlates of these cortical lesions with a novel approach, i.e. by comparing two samples of relapsing-remitting multiple sclerosis (RRMS) patients, one group with and the other without cortical lesions.

METHODS

High-resolution structural MRI was acquired from 42 RRMS patients and 43 controls (HC). The patient group was dichotomized based on the presence versus absence of DIR-hyperintense cortex-involving lesions, resulting in a cortical lesion group (CL, n = 32) and a non-cortical lesion group (nCL, n =10). Cognitive functioning was assessed in all participants with a comprehensive neuropsychological battery, covering mnestic, executive, and attentional functions.

RESULTS

Highest densities of cortical lesions in the CL group were observed in the bilateral parahippocampal gyrus. Relative to HC, patients with cortical lesions - but not those without - showed significant global cortical thinning and mnestic deficits. The two patient groups did not differ from each other regarding demographic and basic disease characteristics such as EDSS scores.

CONCLUSION

The appearance of cortical lesions in MS patients is associated with cortical thinning as well as mnestic deficits, which might be key characteristics of a 'cortically dominant' MS subtype.

Synergistic Effects of Reserve and Adaptive Personality in Multiple Sclerosis

OBJECTIVES

Cognitive reserve moderates the effects of gray matter (GM) atrophy on cognitive function in neurological disease. Broadly speaking, Reserve explains how persons maintain function in the face of cerebral injury in cognitive and other functional domains (e.g., physical, social). Personality, as operationalized by the Five Factor Model (FFM), is also implicated as a moderator of this relationship. It is conceivable that these protective mechanisms are related. Prior studies suggest links between Reserve and personality, but the degree to which these constructs overlap and buffer the clinical effects of neuropathology is unclear.

METHODS

We evaluated Reserve and FFM traits-Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness-in a cohort of 67 multiple sclerosis (MS) patients. We also examined the extent to which FFM traits and aspects of Reserve interact in predicting cognitive processing speed.

RESULTS

Retrospectively reported educational/occupational achievement was associated with higher Openness, and childhood social engagement was associated with higher Extraversion, Agreeableness, and Conscientiousness. Current involvement in exercise activities and social activities was associated with Extraversion, current involvement in hobbies was associated with Neuroticism, and current receptive behaviors were associated with Agreeableness and Conscientiousness. When tested as predictors, Conscientiousness and childhood enrichment activities interacted in predicting cognitive processing speed after accounting for age, disease duration, disability, and GM volume.

CONCLUSIONS

Childhood enrichment activities and Conscientiousness have a synergistic effect on cognitive processing speed. Current findings have implications for using psychological interventions to foster both Reserve and adaptive personality characteristics to stave off clinical symptoms in MS. (JINS, 2016, 22, 920-927).

["Time is brain" in relapsing remitting multiple sclerosis. Current treatment concepts in immunotherapy]

BACKGROUND

Despite highly divergent time scales of disease evolution in multiple sclerosis (MS) and ischemic stroke, clear analogies are apparent that may point the way to optimization of MS treatment. Inflammatory disease activity and neurodegeneration may induce potentially irreversible damage to central nervous system structures and thus lead to permanent disability. For the treatment of MS early detection of disease activity and early immunotherapy or treatment optimization are pivotal determinants of long-term outcomes. Such therapeutic concepts may be described with the catchy phrase "time is brain" as coined for the acute thrombolytic treatment of ischemic stroke.

RESULTS AND DISCUSSION

For MS a "time is brain" concept would comprise an early initiation of first line therapy as well as sensitive and structured monitoring of disease activity under therapy in conjunction with a low threshold for timely treatment optimization to achieve sustained freedom from measurable disease activity. This approach may substantially improve the long-term outcome in patients who show insufficient response to platform therapies. The intersectorial collaboration in regional MS care networks involving office-based neurologists and specialized MS centers may facilitate the timely use of highly active therapies with their specific benefit-risk profiles thus supporting sustained stabilization of patient quality of life.

Reserve and Reserve-building activities research: key challenges and future directions

Background

The concept of Cognitive Reserve has great appeal and has led to an interesting and important body of research. We believe, however, that it is unnecessarily limited by ‘habits’ of measurement, nomenclature, and intra-disciplinary thinking.

Main body

A broader, more comprehensive way of conceptualizing Reserve is proposed that invokes a broader measurement approach, nomenclature that uses specific terms embedded in a theoretical model, and crosses disciplines.

Conclusion

Building on this comprehensive conceptualization, we will discuss fruitful directions for future research.

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.

Cumulative evidence for MS as a neural network disconnection syndrome consistent with cognitive impairment mechanisms and the confounding role of fatigue and depression-outlook from the Fourth Nordic MS symposium

The Fourth Nordic MS symposium served as a platform to present an overview over the rise and impact of cognitive impairment in people with MS, from early stages on, impairing their quality of life. After discussing MS and cognitive impairment symptoms, a review on the pathophysiology underlying cognitive impairment was given, followed by a talk on neuroimaging highlighting cortical reorganization in MS-affected brains. As a conclusion, therapy and treatment options were discussed. The symposium presented several cutting-edge research studies providing or testing working models that appear successful in predicting and explaining cognitive impairment in MS, such as the disconnection syndrome.

Evaluation of cognition and fatigue in multiple sclerosis: daily practice and future directions

The so-called hidden symptoms or soft signs of multiple sclerosis comprise cognitive dysfunction, fatigue, depression and anxiety. From a patient's perspective, these symptoms are rated as exerting much more negative impact on quality of life and daily functioning than their physical symptoms. Despite this knowledge, the symptoms remain disregarded by many neurologists in clinical practice. This missing awareness can be attributed to several reasons. First, the underlying pathophysiological mechanisms determining occurrence and severity of the different symptoms are still unclear. Second, there is uncertainty in how to reliably assess them. It is undeniable that assessment can be difficult as the hidden symptoms seldom appear isolated but more often highly interact. Third, if standardized, fast and cost-effective assessment to quantify and monitor the evolution of the hidden symptoms would be feasible, the question still remains how to treat these aspects. The present article will give an overview on symptom background and assessment strategies for clinical practice.

Pathology and MRI: exploring cognitive impairment in MS

Cognitive impairment is a frequent symptom in people with multiple sclerosis, affecting up to 70% of patients. This article reviews the published association of cognitive dysfunction with neuroimaging findings. Cognitive impairment has been related to focal T2 hyperintense lesions, diffuse white matter damage and corical and deep gray matter atrophy. Focal lesions cannot sufficiently explain cognitive dysfunction in MS; microstructural tissue damage detectable by diffusion tensor imaging and gray matter atrophy are probably at least as relevant. Resting state functional magnetic resonance imaging is increasingly used to investigate the contribution of functional connectivity changes to cognitive function in MS. The fact that at least one third of MS patients are not overtly cognitively impaired despite significant radiographic tissue damage argues for protective factors (brain reserve, cognitive reserve) that require further clarification. It is concluded that the reported correlations between imaging findings and cognitive function do not imply causality. Well conceived and sufficiently powered longitudinal studies are lacking. Such studies would help unravel protective mechanisms against cogniitve decline and identify suitable imaging techniques to monitor cognitive function in individual patients with MS.

What you get from what you see: Parametric assessment of visual processing capacity in multiple sclerosis and its relation to cognitive fatigue

Multiple sclerosis (MS(1)) is a diffusely disseminated inflammatory disease affecting widespread cerebral networks. Major cognitive impairments are a reduction of processing capacity and mental fatigue, i.e., an "abnormal sense of tiredness or lack of energy". Here, the present study provides the first assessment of the distinct components of visual processing capacity based on a 'theory of visual attention' (TVA(2)) in MS patients and relates it to measures of subjective as well as (more) objective fatigue. The performance of 36 relapsing-remitting MS patients in a whole report task of brief letter arrays was compared to healthy control subjects matched for gender, age and education. Additionally, the sustained attention test PASAT-3(3) served as a measure of objective fatigue, and the self-report questionnaire MFIS(4) as a measure of subjective fatigue. Results indicate generally diminished processing speed as well as iconic memory buffers, and increased perceptual thresholds in MS patients compared to healthy controls. Block-wise analysis of attentional parameters shows that the processing speed performance of MS patients declines in the second half of the TVA-based test compared to healthy controls and in particular for patients with high versus low objective fatigue. These findings describe which aspects of processing capacity are impaired in MS, and show that fatigue mainly affects speed of processing. Thus, TVA-based assessment provides a novel approach in the determination of cognitive impairments and fatigue in MS. However, further research is required to elucidate the complex relations of processing capacity and cognitive functions in MS.

Brain health: time matters in multiple sclerosis

INTRODUCTION

We present international consensus recommendations for improving diagnosis, management and treatment access in multiple sclerosis (MS). Our vision is that these will be used widely among those committed to creating a better future for people with MS and their families.

METHODS

Structured discussions and literature searches conducted in 2015 examined the personal and economic impact of MS, current practice in diagnosis, treatment and management, definitions of disease activity and barriers to accessing disease-modifying therapies (DMTs).

RESULTS

Delays often occur before a person with symptoms suggestive of MS sees a neurologist. Campaigns to raise awareness of MS are needed, as are initiatives to improve access to MS healthcare professionals and services. We recommend a clear treatment goal: to maximize neurological reserve, cognitive function and physical function by reducing disease activity. Treatment should start early, with DMT and lifestyle measures. All parameters that predict relapses and disability progression should be included in the definition of disease activity and monitored regularly when practical. On suboptimal control of disease activity, switching to a DMT with a different mechanism of action should be considered. A shared decision-making process that embodies dialogue and considers all appropriate DMTs should be implemented. Monitoring data should be recorded formally in registries to generate real-world evidence. In many jurisdictions, access to DMTs is limited. To improve treatment access the relevant bodies should consider all costs to all parties when conducting economic evaluations and encourage the continuing investigation, development and use of cost-effective therapeutic strategies and alternative financing models.

CONCLUSIONS

The consensus findings of an international author group recommend a therapeutic strategy based on proactive monitoring and shared decision-making in MS. Early diagnosis and improved treatment access are also key components.

Automated brain volumetrics in multiple sclerosis: a step closer to clinical application

BACKGROUND

Whole brain volume (WBV) estimates in patients with multiple sclerosis (MS) correlate more robustly with clinical disability than traditional, lesion-based metrics. Numerous algorithms to measure WBV have been developed over the past two decades. We compare Structural Image Evaluation using Normalisation of Atrophy-Cross-sectional (SIENAX) to NeuroQuant and MSmetrix, for assessment of cross-sectional WBV in patients with MS.

METHODS

MRIs from 61 patients with relapsing-remitting MS and 2 patients with clinically isolated syndrome were analysed. WBV measurements were calculated using SIENAX, NeuroQuant and MSmetrix. Statistical agreement between the methods was evaluated using linear regression and Bland-Altman plots. Precision and accuracy of WBV measurement was calculated for (1) NeuroQuant versus SIENAX and (2) MSmetrix versus SIENAX.

RESULTS

Precision (Pearson's r) of WBV estimation for NeuroQuant and MSmetrix versus SIENAX was 0.983 and 0.992, respectively. Accuracy (Cb) was 0.871 and 0.994, respectively. NeuroQuant and MSmetrix showed a 5.5% and 1.0% volume difference compared with SIENAX, respectively, that was consistent across low and high values.

CONCLUSIONS

In the analysed population, NeuroQuant and MSmetrix both quantified cross-sectional WBV with comparable statistical agreement to SIENAX, a well-validated cross-sectional tool that has been used extensively in MS clinical studies.

The Rao's Brief Repeatable Battery in the study of cognition in different multiple sclerosis phenotypes: application of normative data in a Serbian population

Cognitive impairment is prevalent in multiple sclerosis (MS) occurring in 43-72 % of patients with all MS phenotypes. The aim of our study was to assess cognitive performance in different MS subtypes in Serbian population. Rao's Brief Repeatable Battery of neuropsychological tests (BRB-N) was administered to 168 MS patients [37 patients with clinically isolated syndrome (CIS) suggestive of MS, 65 with relapsing-remitting MS (RRMS), 31 with secondary progressive MS (SPMS) and 35 patients with primary progressive MS (PPMS)]. The percentage of cognitively impaired patients in our total MS cohort was 58.9 %. Prevalence of cognitive dysfunction was 40.5 % in CIS group, 36.9 % in RRMS, 96.8 % in SPMS, and 85.7 % in PPMS group. Patients in CIS and RRMS groups performed consistently better all tests of the Rao's battery than patients in SPMS and PPMS cohort. CIS and RRMS groups performed consistently better in all tests of the Rao's battery than SPMS and PPMS cohort. Additionally, difference in the performance of any of the BRB-N tests was not found between CIS and RRMS. However, there was a significant difference between SPMS and PPMS patients in the performance on five tests of Rao's battery. Statistical significance (p < 0.05) in favor of PPMS patients was demonstrated for the following tasks: SRT_lts, SRT_cltr, SDMT, SRT_D, SPART_D. Our study demonstrates that cognitive impairment is frequent in all MS phenotypes. Furthermore, we have found that cognitive deficit is most severe and most frequent in SPMS patients, followed by PPMS subjects and then CIS and RRMS patients.