Cognitive Impairment in Multiple Sclerosis: A Review of Neuropsychological Assessments

Cross-Cultural Adaptation and Spanish Validation of the Computerized Information Processing Assessment Battery (COGNITO)

INTRODUCTION

Mild cognitive impairment (CI) has an exponential increase in its prevalence and causes functional deficits and dependence. Its early detection allows for timely treatment and greater therapeutic efficacy. However, mild cognitive impairment (MCI) is currently underdiagnosed. Although recent decades have seen a rise in computerized instruments for the detection and early diagnosis of MCI, showing numerous advantages over the classic paper-and-pencil methods, such as standardized stimulus presentation. However, their limitations include the use of self-administered application without professional supervision. Few of these instruments have Spanish-adapted versions.

OBJECTIVE

To translate, adapt, and validate the computerized Information Processing Assessment Battery (COGNITO) battery in the Spanish population and to develop a portable administration system that facilitates its application in different settings. COGNITO was then administered to 232 Spanish participants (18-89 years) without cognitive impairment, after which preliminary normative data were obtained.

RESULTS

Strong positive correlations were found between the main cognitive domains assessed by COGNITO and the variables of age, educational level, and MEC score. The gender variable only correlated with visuospatial skills, with men outperforming women. The test-retest correlations conducted after 4 weeks with 89 participants revealed adequate reliability coefficients ranging between.63 and.66 (visuospatial skills = 0.35). Internal consistency coefficients were satisfactory in Attention-Executive Functions and Memory domains.

CONCLUSIONS

The Spanish adaptation of COGNITO shows adequate psychometric characteristics of validity and reliability. The preliminary normative data provided may contribute to the early detection of cognitive impairments associated with both normal aging and various types of neurological pathology. This tool has great utility and versatility for neuropsychological practice.

Predictive value of brain atrophy, serum biomarkers and information processing speed for early disease progression in multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a chronic autoimmune-mediated demyelinating disease of the central nervous system (CNS). A clinical presentation of the disease is highly differentiated even from the earliest stages of the disease. The application of stratifying tests in clinical practice would allow for improving clinical decision-making including a proper assessment of treatment benefit/risk balance.

METHODS

This prospective study included patients with MS diagnosed up to 1 year before recruitment. We analyzed serum biomarkers such as CXCL13, CHI3L1, OPN, IL-6, and GFAP and neurofilament light chains (NfLs); brain MRI parameters of linear atrophy such as bicaudate ratio (BCR), third ventricle width (TVW); and information processing speed were measured using the Symbol Digit Modalities Test (SDMT) during the 2 years follow-up.

RESULTS

The study included a total of 50 patients recruited shortly after the diagnosis of MS diagnosis (median 0 months; range 0-11 months), and the mean time of observation was 28 months (SD = 4.75). We observed a statistically significant increase in the EDSS score (Wilcoxon test: Z = 3.06, p = 0.002), BCR (Wilcoxon test: Z = 4.66, p < 0.001), and TVW (Wilcoxon test: Z = 2.84, p = 0.005) after 2 years of disease. Patients who had a significantly higher baseline level of NfL suffered from a more severe disease course as per the EDSS score (Mann-Whitney U-test: U = 107, Z = -2,74, p = 0.006) and presence of relapse (Mann-Whitney U-test: U = 188, Z = -2.01, p = 0.044). In the logistic regression model, none of the parameters was a significant predictor for the achieving of no evidence of disease activity status (NEDA). In the model considering all assessed parameters, only the level of NfL had a significant impact on disease progression, measured as the increase in EDSS (logistic regression: β = 0.002, p = 0.017).

CONCLUSION

We confirmed that NfL levels in serum are associated with more active disease. Moreover, we found that TVW at the time of diagnosis was associated with an impairment in cognitive function measured by information processing speed at the end of the 2-year observation. The inclusion of serum NfL and TVW assessment early in the disease may be a good predictor of disease progression independent of NEDA.

Examining electroencephalogram signatures of people with multiple sclerosis using a nonlinear dynamics approach: a systematic review and bibliographic analysis

Background

Considering that brain activity involves communication between millions of neurons in a complex network, nonlinear analysis is a viable tool for studying electroencephalography (EEG). The main objective of this review was to collate studies that utilized chaotic measures and nonlinear dynamical analysis in EEG of multiple sclerosis (MS) patients and to discuss the contributions of chaos theory techniques to understanding, diagnosing, and treating MS.

Methods

Using the preferred reporting items for systematic reviews and meta-analysis (PRISMA), the databases EbscoHost, IEEE, ProQuest, PubMed, Science Direct, Web of Science, and Google Scholar were searched for publications that applied chaos theory in EEG analysis of MS patients.

Results

A bibliographic analysis was performed using VOSviewer software keyword co-occurrence analysis indicated that MS was the focus of the research and that research on MS diagnosis has shifted from conventional methods, such as magnetic resonance imaging, to EEG techniques in recent years. A total of 17 studies were included in this review. Among the included articles, nine studies examined resting-state, and eight examined task-based conditions.

Conclusion

Although nonlinear EEG analysis of MS is a relatively novel area of research, the findings have been demonstrated to be informative and effective. The most frequently used nonlinear dynamics analyses were fractal dimension, recurrence quantification analysis, mutual information, and coherence. Each analysis selected provided a unique assessment to fulfill the objective of this review. While considering the limitations discussed, there is a promising path forward using nonlinear analyses with MS data.

Cognitive reserve as a moderating factor between EDSS and cognition in multiple sclerosis

OBJECTIVES

It is now well recognized that brain damage and/or atrophy apparent on MRI is only moderately correlated to cognitive functioning. The cognitive reserve (CR) hypothesis has been proposed to explain this functional heterogeneity, but it has only been addressed recently in the MS literature and has not yet been thoroughly investigated. The objective of this study is to examine the protective role of CR in cognition using a standardized CR tool in a population with a wide age range.

METHODS

A neuropsychological evaluation was performed on 84 pwMS aged between 27 and 78 years old and the CR Index questionnaire (CRIq) was used to estimate CR. The EDSS scale was used to assess the degree of neurologic impairment and estimate the disease burden.

RESULTS

A moderating effect of CR was observed in the relationship between EDSS score and specific cognitive domains: processing efficiency, visuospatial learning and memory, as well as a tendency for verbal memory. In pwMS with a high level of CR, there was no negative relationship between these cognitive domains and EDSS.

CONCLUSION

The results support the protective role of CR in a sample of pwMS with a wide age range. This role seems to be limited to specific cognitive tasks that pose a greater challenge and therefore require greater adaptability.

Cognitive impairment in people with multiple sclerosis: Perception vs. performance - factors that drive perception of impairment differ for patients and clinicians

BACKGROUND

Neurologists' perceptions of the presence of cognitive impairment (CI) in people with multiple sclerosis (PwMS) may not always align with findings of objective cognitive assessment. The accuracy of self-reported CI in PwMS can also be highly variable across individuals, and may not align with objective measurement of cognitive disturbances. Research suggests that additional factors impact perceived cognitive ability, such as depression and fatigue. Objective cognitive screening regardless of patient or neurologist perception has been recommended but still is often limited in routine care. Moreover, comprehensive neuropsychological assessment is even less routinely done.

OBJECTIVE

To explore how neurologists' perceptions of PwMS' CI compare to the perception of the patient by determining whether PwMS and their clinicians are accurate in detecting the presence and degree of CI as defined by a multi-domain validated computerized test battery in PwMS, as well as investigate what factors influence perception of CI in each group.

METHODS

PwMS completed a computerized multi-domain cognitive testing battery, and self-reported measures of disease impact (MSIS-29), fatigue (MFIS), and depression (BDI-II). Disability was assessed by the clinician using the Expanded Disability Status Scale (EDSS). Clinicians and patients also provided an estimation of cognitive deficits along a Likert scale.

RESULTS

In this cohort of PwMS (N=202, age range: 20 to 88, gender: 71% female), their level of accuracy in detecting attention deficits (k = -.028, p = .010) was low but statistically significant. In contrast, clinicians' accuracy in detecting global CI (k = -.037, p < .001) and a number of specific domain deficits was moderate. Fatigue (p < .001) and cognitive performance (p = .012) significantly predicted patient perceived cognitive deficits. Clinician perceived cognitive performance was significantly predicted by multiple factors: cognitive scores (p < .001), physical disability (p = .011), age (p = .021), and depression (p = .038).

CONCLUSION

The need to objectively screen for CI in PwMS, regardless of perception, can be aided by a better understanding of the agreement and discrepancies between the patient and clinician regarding perceived cognitive disturbances and the presence of CI defined by a multi-dimensional objective screening battery.

Altered functional connectivity during performance feedback processing in multiple sclerosis

Effective learning from performance feedback is vital for adaptive behavior regulation necessary for successful cognitive performance. Yet, how this learning operates in clinical groups that experience cognitive dysfunction is not well understood. Multiple sclerosis (MS) is an autoimmune, degenerative disease of the central nervous system characterized by physical and cognitive dysfunction. A highly prevalent impairment in MS is cognitive fatigue (CF). CF is associated with altered functioning within cortico-striatal regions that also facilitate feedback-based learning in neurotypical (NT) individuals. Despite this cortico-striatal overlap, research about feedback-based learning in MS, its associated neural underpinnings, and its sensitivity to CF, are all lacking. The present study investigated feedback-based learning ability in MS, as well as associated cortico-striatal function and connectivity. MS and NT participants completed a functional magnetic resonance imaging (fMRI) paired-word association task during which they received trial-by-trial monetary, non-monetary, and uninformative performance feedback. Despite reporting greater CF throughout the task, MS participants displayed comparable task performance to NTs, suggesting preserved feedback-based learning ability in the MS group. Both groups recruited the ventral striatum (VS), caudate nucleus, and ventromedial prefrontal cortex in response to the receipt of performance feedback, suggesting that people with MS also recruit cortico-striatal regions during feedback-based learning. However, compared to NT participants, MS participants also displayed stronger functional connectivity between the VS and task-relevant regions, including the left angular gyrus and right superior temporal gyrus, in response to feedback receipt. Results indicate that CF may not interfere with feedback-based learning in MS. Nonetheless, people with MS may recruit alternative connections with the striatum to assist with this form of learning. These findings have implications for cognitive rehabilitation treatments that incorporate performance feedback to remediate cognitive dysfunction in clinical populations.

Cognitive measures used in adults with multiple sclerosis: A systematic review

Cognitive problems are common in people with Multiple Sclerosis (MS), and researchers and clinicians have used a vast array of measures to assess cognition. Our aim was to systematically identify cognitive measures routinely used in MS research, and outline their different uses. Previous recommendations of cognitive measures to use in MS have relied on expert consensus approaches. We believe this systematic review is a starting point for an evidence-based approach to recommend cognitive tests for use with people with MS. We systematically searched electronic databases using relevant search terms for studies that assessed cognitive functioning in MS (last search in February 2020). From 11,854 abstracts retrieved, based on title and abstract review, 2563 remained. Data were extracted from 1526 studies. Studies used 5665 measures of cognition, with 316,053 people with MS. Substitutional style tests, serial addition tests, and word list learning tests were the most commonly used individual tests, and the Brief Repeatable Battery of Neuropsychological Tests was the most commonly used battery. Some of the most frequently used measures were potentially inappropriate due to measuring irrelevant domains of cognition, and issues with sensitivity. Further research is needed to ascertain the psychometric properties, and acceptability of measures for people with MS.

Demographic Patterns of MS Patients Using BRISA: An MS-Specific App in Germany

Background: Multiple sclerosis (MS) is a chronic, progressive neurological autoimmune disease impacting quality of life. BRISA is an app designed to help MS patients in Germany track their disease course by symptom-monitoring. This study aimed to understand demographic and health-related characteristics of BRISA users. Methods: Demographic data provided by 2095 users were analyzed to describe characteristics such as sex, age, type of MS, and medication. The distribution of tracked symptoms based on age and time since diagnosis were studied. Furthermore, the covariance of specific symptom pairs was analyzed. Results: BRISA users are predominantly female and between 26 and 55 years old. Relapsing–remitting MS was the most prevalent form of MS. First-line category 1 drugs were most frequently used, followed by high-efficacy category 3 drugs (e.g., monoclonal antibodies). The relative frequencies of use of category 1 and category 2 drugs (e.g., spingosine-1-phosphate-receptor modulators) significantly altered with time since diagnosis. Fatigue, concentration disorders, tingling, forgetfulness, and pain were the top five symptoms affecting users. Conclusion: The results highlight the diversity among MS patients and the need for extensive cohort characterization in the real-world scenario. In-depth analysis could help in identifying novel insights that could aid in disease management.

Initial Adaptation of the General Cognitive Assessment Battery by Cognifit™ for Bulgarian Older Adults

BACKGROUND

Online neuropsychological assessment batteries may facilitate the screening of cognitive functions in older adults and could be useful for early diagnosis and detection of cognitive impairments.

OBJECTIVE

The primary aim of this study was to assess the psychometric qualities of an online multi-domain cognitive assessment battery (General Cognitive Assessment Battery (GCAB) by Cognifit™) applied for the first time in Bulgaria.

METHODS

A total of 20 healthy older adults (6 male and 14 female, aged 60-82) completed the GCAB as well as the Mini-Mental State Examination (MMSE) and the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery. Descriptive statistics were used to describe the demographic characteristics of the sample and the scores on the GCAB and the CERAD battery. The internal consistency of the GCAB was evaluated using item analysis and measured with Cronbach's alpha. The concurrent validity of the GCAB was assessed with respect to the CERAD using Spearman's r after verifying the linear relationship between the GCAB and CERAD scores.

RESULTS

The GCAB showed good concurrent validity when compared with the corresponding CERAD tests. The correlation coefficients ranged from 0.67 for working memory to 0.47 for short-term auditory memory. We found very good reliability of the GCAB, with the inter-class correlation coefficient higher than 0.8 for all cognitive domains. There were no significant correlations between MMSE and GCAB scores.

CONCLUSION

The GCAB was found to be valid for the cognitive screening of Bulgarian healthy older adults and may provide an adequate assessment of their cognitive status. The GCAB showed good concurrent validity when compared with the CERAD battery, measuring similar cognitive constructs. Further work is necessary to explore its validity and reliability.

Is computerized screening for processing speed impairment sufficient for identifying MS-related cognitive impairment in a clinical setting?

BACKGROUND

Annual screening for processing speed impairment (PSI) is recommended for patients with multiple sclerosis (pwMS). However, cognitive deficits in pwMS are heterogeneous, and whether PSI screening identifies patients with impairment in other cognitive domains is unclear. The objective of this study was to examine sensitivity and specificity of the self-administered, computerized Processing Speed Test (PST) in identifying cognitive impairment defined by a comprehensive neuropsychological battery (NPT).

METHODS

Ninety-one pwMS completed PST and NPT, with raw scores demographically adjusted. Cognitive impairment on NPT was defined as performance <5^th percentile in at least one domain. Receiver operating characteristic (ROC) analyses were performed to determine the ability of the PST to discriminate between cognitively normal (CN) and cognitively impaired with PSI (CI-PSI) and cognitively impaired with normal processing speed (CI-PSN) groups.

RESULTS

Cognitive impairment was observed in 23.1% of pwMS on PST and in 42.9% on NPT. PST demonstrated excellent ability to discriminate between CN (57.1%) and CI-PSI (20.9%) groups (Area Under the Curve [AUC] = 0.86, p < 0.001). In contrast, PST was unable to discriminate CN and CI-PSN (22.0%) groups (AUC = 0.42, p = 0.32).

CONCLUSION

The PST demonstrates excellent ability to detect PSI in pwMS but is unable to identify cognitively impaired pwMS without PSI, highlighting the importance of developing additional screening measures.

Predicting Neuropsychological Impairment in Relapsing Remitting Multiple Sclerosis: The Role of Clinical Measures, Treatment, and Neuropsychiatry Symptoms

OBJECTIVE

This retrospective observational study aimed to define neuropsychological impairment (NI) profiles and determine the influence of clinical, demographic, and neuropsychiatric measures in specific cognitive domains in a cohort of relapsing-remitting multiple sclerosis (RRMS) patients.

METHODS

Ninety-one RRMS patients underwent a neurological examination and a brief neuropsychological assessment. Patients were classified according to the disease-modifying therapies (DMTs) received (platform or high-efficacy). Differences between groups and multiple regression analyses were performed to determine the predictive value of the assessed measures in cognitive performance.

RESULTS

More than two-thirds of the patients showed NI. Specifically, mild to moderate NI was presented in approximately half of the participants. Paced Auditory Serial Addition Test (PASAT-3) and Symbol Digit Modalities Test (SDMT) were the most frequently impaired cognitive tests (45.3% and 41.3%, respectively) followed by phonemic verbal fluency (PVF) (27.8%). Expanded Disability Status Scale (EDSS), age, depressive symptoms, and disease duration were the best predictors of SDMT (R2 = .34; p < .01), whereas disease duration, EDSS, and anxiety-state levels predicted PASAT-3 (R2 = .33, p < .01). Educational level, age, EDSS, and depressive symptoms demonstrated the strongest association with PVF (R2 = .31, p < .01).

CONCLUSIONS

Our results indicated a significant prevalence of NI in RRMS patients that was not dependent on the DMT type. In addition to the meaningful working memory (PASAT-3) and information processing speed (SDMT) impairments found, PVF deficits may also be an important marker of cognitive impairment in RRMS patients. This study supports the relevance of standard clinical measures and reinforces the importance of quantifying clinical and neuropsychiatric symptoms to predict subsequent cognitive performance on a similar multiple sclerosis phenotype and disease stage.

Cognition in acute relapses: A psychometric evaluation and its correlation with event-related potential, P300 in multiple sclerosis

OBJECTIVE

During acute relapses of multiple sclerosis (MS), physical symptoms attract utmost care. However, cognitive impairment may constitute an substantial part of a new relapse. In this study, we evaluated the cognitive status of MS patients during acute relapses.

MATERIALS AND METHODS

We enrolled 35 definite MS patients and 21 healthy subjects. Neuropsychometric tests and the event-related potential, P300 were administered to the MS patients before corticosteroid treatment, and 3 months later. The control subjects were tested only once.

RESULTS

The differences between the scores of the Timed 25-Foot Walk test, the Brief Repeatable Battery subtests (10/36 SPART, SDMT, SRT, SRT-LTM) in the relapse and remission phases were statistically significant (p = .005, p = .007, p = .05, p = .029, p = .001, respectively). The latencies of P300 waves during the relapses were significantly prolonged than the ones in the remission and the controls' (p = .004, p < .001, respectively).

CONCLUSIONS

In this study, we observed a significant involvement of visual-spatial perception, remote memory, and recall, as well as P300 latencies in acute relapses. The inclusion of cognitive assessment during a relapse can provide accurate information on cognitive status for future treatment modalities.

The effects of aging and disease duration on cognition in multiple sclerosis

OBJECTIVES

Multiple sclerosis (MS) is a disease of the central nervous system that can interfere with cognitive functions. The purpose of this study is to document the impact of MS, aging and disease duration on cognitive functioning as both life expectancy and incidence of the disease among persons with MS (PwMS) aged 50 years and over (late-onset MS) are increasing in the last two decades.

METHODS

Exhaustive neuropsychological evaluation was performed in 84 PwMS (30 young, 30 elderly adult-onset, 25 elderly late-onset) and 50 control participants (25 young, 24 elderly). ANCOVAs and hierarchical linear regressions were used to meet the objectives.

RESULTS

Interaction effects were found between age and presence of MS on higher executive function and information processing speed/working memory. After controlling for confounding variables (fatigue, quality of life, depression, MS course, comorbidity), results demonstrated an important role of age on all cognitive functions but only a trend of disease duration on information processing speed/working memory.

CONCLUSION

Decline in higher executive functions and information processing speed/working memory in aging is accentuated by the presence of MS, but the impact of age and MS on memory are independent. Age appears to be the variable having the most important role on cognition.

Graph Theoretic Analysis of Brain Connectomics in Multiple Sclerosis: Reliability and Relationship with Cognition

Research suggests that disruption of brain networks might explain cognitive deficits in multiple sclerosis (MS). The reliability and effectiveness of graph theoretic network metrics as measures of cognitive performance were tested in 37 people with MS and 23 controls. Specifically, relationships with cognitive performance (linear regression against the paced auditory serial addition test-3 seconds [PASAT-3], symbol digit modalities test [SDMT], and attention network test) and 1-month reliability (using the intraclass correlation coefficient [ICC]) of network metrics were measured using both resting-state functional and diffusion magnetic resonance imaging data. Cognitive impairment was directly related to measures of brain network segregation and inversely related to network integration (prediction of PASAT-3 by small worldness, modularity, characteristic path length, R² = 0.55; prediction of SDMT by small worldness, global efficiency, and characteristic path length, R² = 0.60). Reliability of the measures for 1 month in a subset of nine participants was mostly rated as good (ICC >0.6) for both controls and MS patients in both functional and diffusion data, but was highly dependent on the chosen parcellation and graph density, with the 0.2–0.5 density range being the most reliable. This suggests that disrupted network organization predicts cognitive impairment in MS and its measurement is reliable for a 1-month period. These new findings support the hypothesis of network disruption as a major determinant of cognitive deficits in MS and the future possibility of the application of derived metrics as surrogate outcomes in trials of therapies for cognitive impairment.

Frontoparietal connectivity correlates with working memory performance in multiple sclerosis

Working Memory (WM) impairment is the most common cognitive deficit of patients with Multiple Sclerosis (MS). However, evidence of its neurobiological mechanisms is scarce. Here we recorded electroencephalographic activity of twenty patients with relapsing-remitting MS and minimal cognitive deficit, and 20 healthy control (HC) subjects while they solved a WM task. In spite of similar performance, the HC group demonstrated both a correlation between temporoparietal theta activity and memory load, and a correlation between medial frontal theta activity and successful memory performances. MS patients did not show theses correlations leading significant differences between groups. Moreover, cortical connectivity analyses using granger causality and phase-amplitude coupling between theta and gamma revealed that HC group, but not MS group, presented a load-modulated progression of the frontal-to-parietal connectivity. This connectivity correlated with working memory capacity in MS groups. This early alterations in the oscillatory dynamics underlaying working memory could be useful for plan therapeutic interventions.

Detecting Subtle Cognitive Impairment in Multiple Sclerosis with the Montreal Cognitive Assessment

BACKGROUND

Although cognitive deficits are frequent in multiple sclerosis (MS), screening for them with tools such as the Montreal Cognitive Assessment (MoCA) test is usually not performed unless there is a subjective complaint. The Multiple Sclerosis Neuropsychological Questionnaire (MSNQ) is among the instruments most commonly used to assess self-reported subjective complaints in MS. Nonetheless, it does not always accurately reflect cognitive status; many patients with cognitive deficits thus fail to receive appropriate referral for detailed neuropsychological evaluation. The objective of this study was to examine the validity of the MoCA test to detect the presence of objective cognitive deficits among patients with MS without subjective complaints using the Minimal Assessment of Cognitive Function in MS (MACFIMS) as the gold standard.

METHODS

The sample included 98 patients who were recruited from a university hospital MS clinic. The MSNQ was used to select patients without subjective cognitive complaints who also completed the MACFIMS, MoCA test and MSQOL-54.

RESULTS

23.5% of patients without subjective cognitive complaints had evidence of objective cognitive impairment on the MACFIMS (z score < -1.5 on two or more tests). The MoCA had a sensitivity of 87% and a specificity of 68% for detecting objective cognitive impairment in this patient population using a cut-off score of 27.

CONCLUSION

A significant proportion of patients without self-reported cognitive impairment do have evidence of cognitive deficits on more exhaustive cognitive assessment. The MoCA is a rapid screening test that could be used to target patients for whom a more detailed neuropsychological assessment would be recommended.

Cognitive Dysfunction in the Early Stages of Multiple Sclerosis-How Much and How Important?

Purpose of Review

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system that mainly affects young adults and that is one of the leading causes of disability in this age group, with cognitive impairment occurring early in the course of the disease. This article summarizes the current knowledge about cognitive dysfunction in the early phase of MS, including biomarkers, MRI correlates, and its value as a prognostic marker.

Recent Findings

New sets of neuropsychological tests have been established to screen for cognitive dysfunction more easily and accurately. Moreover, structural changes detected by brain MRI and several biomarkers found in cerebrospinal fluid and blood serum have been recently correlated with decreased cognitive performance. Additionally, factors influencing cognition in MS, such as disease-modifying therapy, mood disorders, and lifestyle, are better described.

Summary

Cognitive impairment early in the course of MS is suggested as a prognostic factor for disease progression. However, clear-cut definitions of the early stage of MS as well as unified criteria for the diagnosis of cognitive impairment are still lacking. New and more reliable tools for evaluating cognition in MS patients should be developed and introduced into everyday practice to facilitate the implementation of effective disease-modifying therapy, cognitive rehabilitation, and lifestyle management.

Cognitive disturbances in the cuprizone model of multiple sclerosis

Cognitive problems frequently accompany neurological manifestations of multiple sclerosis (MS). However, during screening of preclinical candidates, assessments of behaviour in mouse models of MS typically focus on locomotor activity. In the present study, we analysed cognitive behaviour of 9 to 10-week-old female C57Bl/6J mice orally administered with the toxin cuprizone that induces demyelination, a characteristic feature of MS. Animals received 400 mg/kg cuprizone daily for 2 or 4 weeks, and their performance was compared with that of vehicle-treated mice. Cuprizone-treated animals showed multiple deficits in short touchscreen-based operant tasks: they responded more slowly to visual stimuli, rewards and made more errors in a simple rule-learning task. In contextual/cued fear conditioning experiments, cuprizone-treated mice showed significantly lower levels of contextual freezing than vehicle-treated mice. Diffusion tensor imaging showed treatment-dependent changes in fractional anisotropy as well as in axial and mean diffusivities in different white matter areas. Lower values of fractional anisotropy and axial diffusivity in cuprizone-treated mice indicated developing demyelination and/or axonal damage. Several diffusion tensor imaging measurements correlated with learning parameters. Our results show that translational touchscreen operant tests and fear conditioning paradigms can reliably detect cognitive consequences of cuprizone treatment. The suggested experimental approach enables screening novel MS drug candidates in longitudinal experiments for their ability to improve pathological changes in brain structure and reverse cognitive deficits.

Design, Development, and Testing of an App for Dual-Task Assessment and Training Regarding Cognitive-Motor Interference (CMI-APP) in People With Multiple Sclerosis: Multicenter Pilot Study

Background

Dual tasking constitutes a large portion of most activities of daily living; in real-life situations, people need to not only maintain balance and mobility skills, but also perform other cognitive or motor tasks at the same time. Interest toward dual-task training (DTT) is increasing as traditional interventions may not prepare patients to adequately face the challenges of most activities of daily living. These usually involve simultaneous cognitive and motor tasks, and they often show a decline in performance. Cognitive-motor interference (CMI) has been investigated in different neurological populations, but limited evidence is present for people with multiple sclerosis (MS). The use of computerized tools is mandatory to allow the application of more standardized assessment and rehabilitation intervention protocols and easier implementation of multicenter and multilanguage studies.

Objective

To describe the design and development of CMI-APP, an adaptive and interactive technology tablet-based app, and to present the preliminary results of a multicenter pilot study involving people with MS performed in several European centers for evaluating the feasibility of and adherence to a rehabilitation program based on CMI-APP.

Methods

CMI-APP includes user-friendly interfaces for personal data input and management, assessment of CMI, and DTT. A dedicated team developed CMI-APP for Android tablets above API level 14 (version 4.0), using C# as the programming language and Unity and Visual Studio as development tools. Three cognitive assessment tests for working memory, information processing speed, and sustained attention and four motor assessment tests for walking at different difficulty levels were implemented. Dual cognitive-motor tasks were performed by combining single cognitive and motor tasks. CMI-APP implements exercises for DTT involving the following 12 cognitive functions: sustained attention, text comprehension, verbal fluency, auditory discrimination, visual discrimination, working memory, information processing speed, auditory memory, visual memory, verbal analog reasoning, visual analog reasoning, and visual spatial planning, which can be performed during walking or stepping on the spot. Fifteen people with MS (mean age 52.6, SD 8.6 years; mean disease duration 9.4, SD 8.4 years; mean Expanded Disability Status Scale score 3.6, SD 1.1) underwent DTT (20 sessions). Adherence to the rehabilitation program was evaluated according to the percentage of performed sessions, perceived exertion during the training (Borg 15-point Ratings of Perceived Exertion [RPE] Scale), and subjective experience of the training (Intrinsic Motivation Inventory [IMI]).

Results

The adherence rate was 91%. DTT was perceived as “somewhat difficult” (mean RPE Scale score 12.6, SD 1.9). IMI revealed that participants enjoyed the training and felt that it was valuable and, to some extent, important, without feelings of pressure. They felt competent, although they did not always feel they could choose the exercises, probably because the therapist chose the exercises and many exercises had few difficulty levels.

Conclusions

CMI-APP is safe, highly usable, motivating, and well accepted for DTT by people with MS. The findings are fundamental for the preparation of future large-sample studies examining CMI and the effectiveness of DTT interventions with CMI-APP in people with MS.

Procedural Learning Improves Cognition in Multiple Sclerosis

Background:

Multiple sclerosis (MS) is considered a neurodegenerative disease and an inflammatory demyelinating neuropathology in young population. Procedural memory has been poorly investigated in MS.

Objective:

We assessed whether the MS group was able to develop a motor-cognitive skill, using a procedural task (PLSC) developed in our laboratory, applying a manual and serial reaction time (RT) paradigm to semantic categorization.

Methods:

We evaluated 26 MS patients and 26 socio-demographic matched control participants using the PLSC task.

Results:

Using non-parametric statistical analyses, we observed a significant improvement of semantic categorization RTs with practice (p = 0.002), even with new verbal material to categorize in MS patients (p = 0.006), despite their motor and executive moderate deficits. This same profile of semantic procedural learning in MS was observed in previous studies carried out with Alzheimer’s and Parkinson’s diseases. Moreover, the visual-motor RTs remained stable or slightly improved over the five blocks in both groups, as well as in the AD groups of previous studies. The MS group showed longer visual-motor reaction times than those of the control group (p < 0.042), except in motor initiation aspect (p = 0.064). Both groups showed no significant differences for any type of error. Additionally, disability level and cognitive performances were not associated with the ratio of semantic procedural learning.

Conclusion:

The present results support the notion that MS patients may be capable of acquiring semantic skill, despite their motor disabilities and executive troubles. This work also addresses the possibilities to improve motor-cognitive skill RTs in neurodegenerative diseases.

Computerized neuropsychological assessment devices in multiple sclerosis: A systematic review

Background:

The proliferation of computerized neuropsychological assessment devices (CNADs) for screening and monitoring cognitive impairment is increasing exponentially. Previous reviews of computerized tests for multiple sclerosis (MS) were primarily qualitative and did not rigorously compare CNADs on psychometric properties.

Objective:

We aimed to systematically review the literature on the use of CNADs in MS and identify test batteries and single tests with good evidence for reliability and validity.

Method:

A search of four major online databases was conducted for publications related to computerized testing and MS. Test–retest reliability and validity coefficients and effect sizes were recorded for each CNAD test, along with administration characteristics.

Results:

We identified 11 batteries and 33 individual tests from 120 peer-reviewed articles meeting the inclusion criteria. CNADs with the strongest psychometric support include the CogState Brief Battery, Cognitive Drug Research Battery, NeuroTrax, CNS-Vital Signs, and computer-based administrations of the Symbol Digit Modalities Test.

Conclusion:

We identified several CNADs that are valid to screen for MS-related cognitive impairment, or to supplement full, conventional neuropsychological assessment. The necessity of testing with a technician, and in a controlled clinic/laboratory environment, remains uncertain.

Motivation in multiple sclerosis cognitive fatigue: An experimental approach

Introduction: Cognitive fatigue is a common symptom in multiple sclerosis (MS). Recent research has implicated dopaminergic pathways originating in the basal ganglia as neurological correlates of cognitive fatigue in MS. This same system has long been associated with goal-directed behavior and reward-based motivation. While researchers have demonstrated that reward has a reliable impact on performance in tasks of sustained attention in healthy individuals, the effect of reward on fatigue is less clear, as prior research has not adequately controlled for desensitization to reward in a sustained attention task. The primary aims of this study were to examine the effect of reward on attention in MS patients, and to examine the effect of reward on objective cognitive fatigue. Method: The study employed a 3 × 3 repeated measures design to evaluate performance of N = 64 patients with definite MS on a measure of cognitive fatigue across several reward conditions. The study utilized a novel delayed-reward paradigm to better control the measured effect of reward on fatigue. Results: Reward (main effect) displayed a significant effect on overall performance (F = 3.050, p < .05). Reward was also shown to affect fatigue trajectory (Reward × Interval, F = 2.433, p < .05). However, this effect was dependent on the method of reward administration. Conclusions: Study findings support the role of motivation in MS cognitive performance, particularly in objective cognitive fatigue, a behavioral finding that is consistent with current neuropsychological theory. Study findings support the delayed-reward paradigm as an effective method for measuring reward effect on tasks of sustained attention.

Performance in daily activities, cognitive impairment and perception in multiple sclerosis patients and their caregivers

Background

The relationship between cognitive assessment results in multiple sclerosis (MS) and performance in daily activities (DAs) remains unclear. Our study aimed to evaluate the relationship between cognitive functions (CF) measured by tests, performance in DAs, and the perception of CF in patients and their caregivers (CG) in MS.

Methods

The Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) battery was used to evaluate cognitive status. We created an ad hoc questionnaire (DaQ) to assess performance in DAs not requiring specific motor skills. We used the Multiple Sclerosis Neuropsychological Questionnaire (MSNQ) to measure each patient self-judgment and caregiver’s perception of CF.

Results

Forty-nine patients and their caregivers were included in the study. Significant correlations were found between the BICAMS and the DaQ (Symbol Digit Modalities Test (SDMT): r = − 0.48, p < 0.001; California Verbal Learning Test (CVLT): r = − 0.33, p = 0.01; Brief Visual Memory Test (BVMT-R): r = − 0.42; p = 0.002); patients self-judgment (SDMT: r = − 0.38, p = 0.004; CVLT: r = − 0.26, p = 0.03); caregiver perception of patient’s CF (SDMT: r = − 0.52, p < 0.001; CVLT: r = − 0.3, p = 0.01; BVMT-R: r = − 0.42, p = 0.002). The difference in perception between the patients and their caregivers was related to patient age (p = 0.001) and severity of cognitive impairment (p = 0.03).

Conclusions

Cognitive assessment results show a significant correlation with performance in daily activities and with patients and, especially, caregiver perception of cognitive impairment. These data support the importance of a routine evaluation of cognitive function in MS that includes an anamnestic evaluation of patients, and, when possible, consideration of the caregiver’s point of view.

Electronic supplementary material

The online version of this article (10.1186/s12883-018-1224-z) contains supplementary material, which is available to authorized users.

Neuropsychology in the Integrated MS Care Setting

The goal of this paper is to describe the role of the neuropsychologist in a Multiple Sclerosis clinic setting. A brief overview of the pathophysiology and neuropsychological deficits in MS is presented. Practical details regarding relations with the neurology team, and the neuropsychologist's focus on assessment are described. Recommendations regarding necessary training and skills, as well as typical clinical practice routines are described. The neuropsychologist's communication with internal and external providers and family members in order to assist implementation of recommendations is described.

Comparison of the abbreviated minimal assessment of cognitive function in multiple sclerosis (aMACFIMS) and the brief international cognitive assessment for multiple sclerosis (BICAMS)

BACKGROUND

Cognitive impairment is a prevalent and often intrusive problem among persons with multiple sclerosis (PwMS). Valid and reliable assessments, including quick screening measures, are crucial. The Brief International Cognitive Assessment for MS (BICAMS) was developed for this reason. While it lends itself to use in locations where formal neuropsychological resources might be limited, it does not include measures of verbal fluency or executive functioning, domains assessed as part of the Minimal Assessment of Cognitive Function in MS (MACFIMS).

OBJECTIVE

Given previous evidence that shortened MACFIMS measures have strong criterion validity, this study aimed to determine which of these should be included in the abbreviated MACFIMS (aMACFIMS), and how the aMACFIMS compares to the BICAMS.

METHODS

One hundred forty-seven PwMS were included in the analyses. A stepwise logistic regression was used to determine the measures in the aMACFIMS. Receiver-operating-characteristic (ROC) curves assessed the classification accuracy, sensitivity, and specificity. The batteries' sensitivity, specificity, and predictive values were then compared.

RESULTS

Compared to the BICAMS, the final aMACFIMS had higher specificity (87% versus 72%) and positive predictive value (86% versus 77%), but lower sensitivity (71% versus 81%).

CONCLUSION

The aMACFIMS has several benefits, including reduced administration time and the addition of a verbal fluency/executive functioning measure.

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.

The interpretation of physical activity, exercise, and sedentary behaviours by persons with multiple sclerosis

OBJECTIVES

This study adopted a qualitative research design with directed content analysis and examined the interpretations of physical activity, exercise, and sedentary behaviour by persons with multiple sclerosis.

METHODS

Fifty three persons with multiple sclerosis who were enrolled in an exercise trial took part in semi-structured interviews regarding personal interpretations of physical activity, exercise, and sedentary behaviours.

RESULTS

Forty three percent of participants indicated a consistent understanding of physical activity, 42% of participants indicated a consistent understanding of exercise, and 83% of participants indicated a consistent understanding of sedentary behaviour with the standard definitions. There was evidence of definitional ambiguity (i.e., 57, 58, and 11% of the sample for physical activity, exercise, and sedentary behaviour, respectively); 6% of the sample inconsistently defined sedentary behaviour with standard definitions. Some participants described physical activity in a manner that more closely aligned with exercise and confused sedentary behaviour with exercise or sleeping/napping.

CONCLUSIONS

Results highlight the need to provide and utilise consistent definitions for accurate understanding, proper evaluation and communication of physical activity, exercise, and sedentary behaviours among persons with multiple sclerosis.

PRACTICE IMPLICATIONS

The application of consistent definitions may minimise ambiguity, alleviate the equivocality of findings in the literature, and translate into improved communication about these behaviours in multiple sclerosis. Implications for Rehabilitation The symptoms of multiple sclerosis can be managed through participation in physical activity and exercise. Persons with multiple sclerosis are not engaging in sufficient levels of physical activity and exercise for health benefits. Rehabilitation professionals should use established definitions of physical activity, exercise, and sedentary behaviours when communicating about these behaviours among persons with multiple sclerosis.

Oxidative stress, prefrontal cortex hypomyelination and cognitive symptoms in schizophrenia

Schizophrenia (SZ) is a neurodevelopmental disorder with a broad symptomatology, including cognitive symptoms that are thought to arise from the prefrontal cortex (PFC). The neurobiological aetiology of these symptoms remains elusive, yet both impaired redox control and PFC dysconnectivity have been recently implicated. PFC dysconnectivity has been linked to white matter, oligodendrocyte (OL) and myelin abnormalities in SZ patients. Myelin is produced by mature OLs, and OL precursor cells (OPCs) are exceptionally susceptible to oxidative stress. Here we propose a hypothesis for the aetiology of cognitive symptomatology in SZ: the redox-induced prefrontal OPC-dysfunctioning hypothesis. We pose that the combination of genetic and environmental factors causes oxidative stress marked by a build-up of reactive oxygen species that, during late adolescence, impair OPC signal transduction processes that are necessary for OPC proliferation and differentiation, and involve AMP-activated protein kinase, Akt-mTOR-P70S6K and peroxisome proliferator receptor alpha signalling. OPC dysfunctioning coincides with the relatively late onset of PFC myelination, causing hypomyelination and disruption of connectivity in this brain area. The resulting cognitive deficits arise in parallel with SZ onset. Hence, our hypothesis provides a novel neurobiological framework for the aetiology of SZ cognitive symptoms. Future research addressing our hypothesis could have important implications for the development of new (combined) antioxidant- and promyelination-based strategies to treat the cognitive symptoms in SZ.

The hidden Niemann-Pick type C patient: clinical niches for a rare inherited metabolic disease

BACKGROUND

Niemann-Pick disease type C (NP-C) is a rare, inherited neurodegenerative disease of impaired intracellular lipid trafficking. Clinical symptoms are highly heterogeneous, including neurological, visceral, or psychiatric manifestations. The incidence of NP-C is under-estimated due to under-recognition or misdiagnosis across a wide range of medical fields. New screening and diagnostic methods provide an opportunity to improve detection of unrecognized cases in clinical sub-populations associated with a higher risk of NP-C. Patients in these at-risk groups ("clinical niches") have symptoms that are potentially related to NP-C, but go unrecognized due to other, more prevalent clinical features, and lack of awareness regarding underlying metabolic causes.

METHODS

Twelve potential clinical niches identified by clinical experts were evaluated based on a comprehensive, non-systematic review of literature published to date. Relevant publications were identified by targeted literature searches of EMBASE and PubMed using key search terms specific to each niche. Articles published in English or other European languages up to 2016 were included.

FINDINGS

Several niches were found to be relevant based on available data: movement disorders (early-onset ataxia and dystonia), organic psychosis, early-onset cholestasis/(hepato)splenomegaly, cases with relevant antenatal findings or fetal abnormalities, and patients affected by family history, consanguinity, and endogamy. Potentially relevant niches requiring further supportive data included: early-onset cognitive decline, frontotemporal dementia, parkinsonism, and chronic inflammatory CNS disease. There was relatively weak evidence to suggest amyotrophic lateral sclerosis or progressive supranuclear gaze palsy as potential niches.

CONCLUSIONS

Several clinical niches have been identified that harbor patients at increased risk of NP-C.