A 3-year longitudinal study of cognitive impairment in patients with primary progressive multiple sclerosis: Speed matters

Current Status of Oral Disease-Modifying Treatment Effects on Cognitive Outcomes in Multiple Sclerosis: A Scoping Review

INTRODUCTION

Cognitive impairment represents one of the most hidden and disabling clinical aspects of multiple sclerosis (MS). In this regard, the major challenges are represented by the need for a comprehensive and standardised cognitive evaluation of each patient, both at disease onset and during follow-up, and by the lack of clear-cut data on the effects of treatments. In the present review, we summarize the current evidence on the effects of the available oral disease-modifying treatments (DMTs) on cognitive outcome measures.

MATERIALS AND METHODS

In this systematised review, we extract all the studies that reported longitudinally acquired cognitive outcome data on oral DMTs in MS patients.

RESULTS

We found 29 studies that evaluated at least one oral DMT, including observational studies, randomised controlled trials, and their extension studies. Most of the studies (n = 20) evaluated sphingosine-1-phosphate (S1P) modulators, while we found seven studies on dimethyl fumarate, six on teriflunomide, and one on cladribine. The most frequently used cognitive outcome measures were SDMT and PASAT. Most of the studies reported substantial stability or mild improvement in cognitive outcomes in a short-time follow-up (duration of most studies ≤2 years). A few studies also reported MRI measures of brain atrophy.

CONCLUSION

Cognitive outcomes were evaluated only in a minority of prospective studies on oral DMTs in MS patients with variable findings. More solid and numerous data are present for the S1P modulators. A standardised cognitive evaluation remains a yet unmet need to better clarify the possible positive effect of oral DMTs on cognition.

Examining the Influence of Cognition on the Relationship Between Backward Walking and Falls in Persons With Multiple Sclerosis

BACKGROUND

Multiple sclerosis (MS) causes motor, cognitive, and sensory impairments that result in injurious falls. Current fall risk measures in MS (ie, forward walking [FW] speed and balance) are limited in their sensitivity. Backward walking (BW) velocity is a sensitive marker of fall risk and correlates with information processing speed (IPS) and visuospatial memory (VSM) in persons with MS. Backward walking is a complex motor task that requires increased cognitive demands, which are negatively affected by MS; however, whether cognitive function modifies the sensitivity of BW as a fall risk assessment in MS remains unknown. This study examines the influence of cognition on the relationship between BW and falls in persons with MS.

METHODS

Measures of BW, FW, IPS, VSM, and retrospective falls were collected. Hierarchical regression tested moderation and included an interaction term predicting number of falls. Covariates for all analyses included age and disease severity.

RESULTS

Thirty-eight persons with MS participated. Although BW, IPS, and covariates significantly predicted the number of falls (R 2 = 0.301; P = .016), there was no evidence of moderation. Backward walking, VSM, and covariates also significantly predicted number of falls (R 2 = 0.332, P = .008), but there was no evidence of moderation. The FW models generated comparable results.

CONCLUSIONS

The relationship between BW velocity and falls was not conditional on IPS or VSM in this sample. Larger-scale studies examining additional cognitive domains commonly affected by MS and prospective falls are needed to characterize neurobiological processes relevant to BW and its clinical application in the assessment of fall risk.

The Use of Smartphone Keystroke Dynamics to Passively Monitor Upper Limb and Cognitive Function in Multiple Sclerosis: Longitudinal Analysis

Background

Typing on smartphones, which has become a near daily activity, requires both upper limb and cognitive function. Analysis of keyboard interactions during regular typing, that is, keystroke dynamics, could therefore potentially be utilized for passive and continuous monitoring of function in patients with multiple sclerosis.

Objective

To determine whether passively acquired smartphone keystroke dynamics correspond to multiple sclerosis outcomes, we investigated the association between keystroke dynamics and clinical outcomes (upper limb and cognitive function). This association was investigated longitudinally in order to study within-patient changes independently of between-patient differences.

Methods

During a 1-year follow-up, arm function and information processing speed were assessed every 3 months in 102 patients with multiple sclerosis with the Nine-Hole Peg Test and Symbol Digit Modalities Test, respectively. Keystroke-dynamics data were continuously obtained from regular typing on the participants’ own smartphones. Press-and-release latency of the alphanumeric keys constituted the fine motor score cluster, while latency of the punctuation and backspace keys constituted the cognition score cluster. The association over time between keystroke clusters and the corresponding clinical outcomes was assessed with linear mixed models with subjects as random intercepts. By centering around the mean and calculating deviation scores within subjects, between-subject and within-subject effects were distinguished.

Results

Mean (SD) scores for the fine motor score cluster and cognition score cluster were 0.43 (0.16) and 0.94 (0.41) seconds, respectively. The fine motor score cluster was significantly associated with the Nine-Hole Peg Test: between-subject β was 15.9 (95% CI 12.2-19.6) and within-subject β was 6.9 (95% CI 2.0-11.9). The cognition score cluster was significantly associated with the Symbol Digit Modalities Test between subjects (between-subject β –11.2, 95% CI –17.3 to –5.2) but not within subjects (within-subject β –0.4, 95% CI –5.6 to 4.9).

Conclusions

Smartphone keystroke dynamics were longitudinally associated with multiple sclerosis outcomes. Worse arm function corresponded with longer latency in typing both across and within patients. Worse processing speed corresponded with higher latency in using punctuation and backspace keys across subjects. Hence, keystroke dynamics are a potential digital biomarker for remote monitoring and predicting clinical outcomes in patients with multiple sclerosis.

Trial Registration

Netherlands Trial Register NTR7268; https://trialsearch.who.int/Trial2.aspx?TrialID=NTR7268

Reliability, construct and concurrent validity of a smartphone-based cognition test in multiple sclerosis

Background:

Early detection and monitoring of cognitive dysfunction in multiple sclerosis (MS) may be enabled with smartphone-adapted tests that allow frequent measurements in the everyday environment.

Objectives:

The aim of this study was to determine the reliability, construct and concurrent validity of a smartphone-adapted Symbol Digit Modalities Test (sSDMT).

Methods:

During a 28-day follow-up, 102 patients with MS and 24 healthy controls (HC) used the MS sherpa^® app to perform the sSDMT every 3 days on their own smartphone. Patients performed the Brief International Cognitive Assessment for MS at baseline. Test–retest reliability (intraclass correlation coefficients, ICC), construct validity (group analyses between cognitively impaired (CI), cognitively preserved (CP) and HC for differences) and concurrent validity (correlation coefficients) were assessed.

Results:

Patients with MS and HC completed an average of 23.2 (SD = 10.0) and 18.3 (SD = 10.2) sSDMT, respectively. sSDMT demonstrated high test–retest reliability (ICCs > 0.8) with a smallest detectable change of 7 points. sSDMT scores were different between CI patients, CP patients and HC (all ps < 0.05). sSDMT correlated modestly with the clinical SDMT (highest r = 0.690), verbal (highest r= 0.516) and visuospatial memory (highest r= 0.599).

Conclusion:

Self-administered smartphone-adapted SDMT scores were reliable and different between patients who were CI, CP and HC and demonstrated concurrent validity in assessing information processing speed.

Neurocognitive impairment and social cognition in multiple sclerosis

PURPOSE/AIM OF THE STUDY

The impairment of neurocognitive functions occurs in all subtypes of multiple sclerosis, even from the earliest stages of the disease. Commonly reported manifestations of cognitive impairment include deficits in attention, conceptual reasoning, processing efficiency, information processing speed, memory (episodic and working), verbal fluency (language), and executive functions. Multiple sclerosis patients also suffer from social cognition impairment, which affects their social functioning. The objective of the current paper is to assess the effect of neurocognitive impairment and its potential correlation with social cognition performance and impairment in multiple sclerosis patients.

MATERIALS AND METHODS

An overview of the available-to-date literature on neurocognitive impairment and social cognition performance in multiple sclerosis patients by disease subtype was performed.

RESULTS

It is not clear if social cognition impairment occurs independently or secondarily to neurocognitive impairment. There are associations of variable strengths between neurocognitive and social cognition deficits and their neural basis is increasingly investigated.

CONCLUSIONS

The prompt detection of neurocognitive predictors of social cognition impairment that may be applicable to all multiple sclerosis subtypes and intervention are crucial to prevent further neural and social cognition decline in multiple sclerosis patients.

Trajectories of Symbol Digit Modalities Test performance in individuals with multiple sclerosis

Background:

Although cognitive problems have been identified in people with multiple sclerosis (PwMS), few studies have investigated the long-term change in cognitive functioning.

Objective:

To identify trajectories of change in cognitive functioning for PwMS.

Methods:

Participants enrolled in the quality-of-life subgroup from the Comprehensive Longitudinal Investigation of Multiple Sclerosis at Brigham and Women’s Hospital (CLIMB) were eligible for our analysis. In 2006, participants in this group began to complete the Symbol Digit Modalities Test (SDMT) annually. Latent trajectory models were used to identify groups of participants with similar longitudinal change in SDMT scores. Linear and quadratic trajectory models were fit, and the models were compared. Latent trajectory models were also fit adjusting for baseline age and disease duration as well as using normalized SDMT scores. The groups identified across the approaches were compared.

Results:

We found that classes with higher-than-average baseline values improved, classes with average baseline values remained relatively constant, and classes with lower baseline values experienced cognitive worsening. Similar results were observed in the alternative latent trajectory models accounting for other variables.

Conclusion:

Our models show that subjects with higher SDMT scores at baseline showed improvement, while subjects with lower SDMT scores at baseline showed worsening. Baseline age and disease duration were also associated with SDMT performance.

Cognitive functions and disability progression in relapsing-remitting multiple sclerosis: A longitudinal study

Longitudinal studies have shown inconsistent findings regarding the association between cognition, demographic characteristics, and clinical decline in relapsing-remitting multiple sclerosis (RRMS). Our objective was to further explore these relations, over time, while also considering age and sex. A total of 183 patients with RRMS were assessed at two time points, using a neuropsychological battery and the Expanded Disability Status Scale (EDSS). For the first assessment, participants were divided by age (<29, 30-39, 40-49, 50-60) and sex. Next, they were divided according to their participation in one of three interval assessment points: 2-3, 4-5, and 6-8 years. Cognitive function was not correlated with disease duration but was negatively correlated with EDSS score. Men under 29 and women under 39 showed negative correlations between cognitive and clinical impairment. Executive functions, attention, and information processing speed (IPS) showed cognitive decline between the first and second assessments. Furthermore, at the 4-5 year interval IPS predicted EDSS scores, while at the 6-8 year interval it was IPS and visuo-spatial ability. Therefore, relation between clinical status and cognition is not consistent across different age and sex groups. Additionally, cognitive deterioration is only partially evident longitudinally; however, IPS appears to be the most sensitive in predicting one's future clinical condition.

Recommendations for cognitive screening and management in multiple sclerosis care

Purpose:

To promote understanding of cognitive impairment in multiple sclerosis (MS), recommend optimal screening, monitoring, and treatment strategies, and address barriers to optimal management.

Methods:

The National MS Society (“Society”) convened experts in cognitive dysfunction (clinicians, researchers, and lay people with MS) to review the published literature, reach consensus on optimal strategies for screening, monitoring, and treating cognitive changes, and propose strategies to address barriers to optimal care.

Recommendations:

Based on current evidence, the Society makes the following recommendations, endorsed by the Consortium of Multiple Sclerosis Centers and the International Multiple Sclerosis Cognition Society:

Evidence of attentional impairments using virtual driving simulation in multiple sclerosis

BACKGROUND

Detection of attentional disorders in complex situation related to daily life activities in multiple sclerosis patients needs better adapted tools than traditional cognitive assessment.

OBJECTIVE

To investigate the usefulness of virtual reality assessment of attention in multiple sclerosis, especially to evaluate alertness and divided attention using driving simulation.

METHODS

In this preliminary study, 11 relapsing-remitting patients (median EDSS: 2; mean disease duration of 10.3 years) and 11 healthy matched controls performed a driving simulation under three conditions (monotonous driving, divided attention driving and urban driving) where Standard Deviation of Lateral position (SDLP) was the main evaluated criteria. In comparison, traditional cognitive assessment of attentional functions was administered (SDMT, alertness and divided attention of TAP battery). Statistical non-parametric Mann-Whitney U tests were used to compare performances between groups in the two types of assessments. Exploratory correlational analyses were further conducted.

RESULTS

No significant difference was observed between groups for traditional attentional assessment except for information processing speed (SDMT; p < 0.01). Considering virtual reality, patients were less efficient than controls on the primary parameter of safe driving (SDLP; p < 0.05). They also committed more errors and omissions (p < 0.01) and speed fluctuations (p < 0.01) during the divided-attention driving condition. Urban driving did not reveal difference between groups. Lack of significant correlations between traditional and virtual reality attentional assessment suggested that they do not evaluate the same cognitive processes.

CONCLUSION

Patients experienced difficulties in maintaining the trajectory and the speed of the simulated vehicle which may be indicative of attentional difficulties, especially alertness and divided attention. These impairments were not revealed by the traditional cognitive assessment. Results of this preliminary study shed new light about the usefulness of virtual reality techniques and their future interest as a part of cognitive rehabilitation programs. They also highlights the need to develop driving preventive measures in MS.

Ecological Momentary Assessment of Pain, Fatigue, Depressive, and Cognitive Symptoms Reveals Significant Daily Variability in Multiple Sclerosis

OBJECTIVE

To describe the daily variability and patterns of pain, fatigue, depressed mood, and cognitive function in persons with multiple sclerosis (MS).

DESIGN

Repeated-measures observational study of 7 consecutive days of home monitoring, including ecological momentary assessment (EMA) of symptoms. Multilevel mixed models were used to analyze data.

SETTING

General community.

PARTICIPANTS

Ambulatory adults (N=107) with MS recruited through the University of Michigan and surrounding community.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

EMA measures of pain, fatigue, depressed mood, and cognitive function rated on a 0 to 10 scale, collected 5 times a day for 7 days.

RESULTS

Cognitive function and depressed mood exhibited more stable within-person patterns than pain and fatigue, which varied considerably within person. All symptoms increased in intensity across the day (all P<.02), with fatigue showing the most substantial increase. Notably, this diurnal increase varied by sex and age; women showed a continuous increase from wake to bedtime, whereas fatigue plateaued after 7 pm for men (wake-bed B=1.04, P=.004). For the oldest subgroup, diurnal increases were concentrated to the middle of the day compared with younger subgroups, which showed an earlier onset of fatigue increase and sustained increases until bed time (wake-3 pm B=.04, P=.01; wake-7 pm B=.03, P=.02). Diurnal patterns of cognitive function varied by education; those with advanced college degrees showed a more stable pattern across the day, with significant differences compared with those with bachelor-level degrees in the evening (wake-7 pm B=-.47, P=.02; wake-bed B=-.45, P=.04).

CONCLUSIONS

Findings suggest that chronic symptoms in MS are not static, even over a short time frame; rather, symptoms-fatigue and pain in particular-vary dynamically across and within days. Incorporation of EMA methods should be considered in the assessment of these chronic MS symptoms to enhance assessment and treatment strategies.

Decline of Neuropsychological Abilities in a Large Sample of Patients with Multiple Sclerosis: A Two-Year Longitudinal Study

OBJECTIVE

In this longitudinal study, we monitored two large groups of multiple sclerosis (MS) patients and healthy controls (HC) for 2 years, with the aim of comparing their neuropsychological profile over time.

METHOD

Three hundred and twenty-two patients with MS and 303 HC were administered the Brief Repeatable Battery of Neuropsychological tests (BRB-N); neuropsychiatric measures were also administered. Two follow-ups were scheduled at 1 and 2 years, respectively.

RESULTS

A linear mixed model (LMM) with random intercept was run by considering participants' performance on each test of the BRB-N at the three assessment points (baseline and follow-ups) as the within-subjects variable, and group (patients and controls) as the between-subjects factor. The interaction term was statistically significant for the tests: Symbol Digit Modalities test (SDMT) (p = 0.044), Paced Auditory Serial Addition test (PASAT) (p = 0.011) and Word List Generation (WLG) (p < 0.001), whereas for the PASAT-3 approached statistical significance (p = 0.05). In addition, a LMM with random intercept was also run by identifying three groups (controls, relapsing-remitting course of MS (i.e. RR-MS), and prog-MS). The interaction term was statistically significant for: PASAT-3 (p = 0.017), PASAT-2 (p = 0.0026), and WLG (p = 0.0022).

CONCLUSIONS

Our results corroborate on a very large scale evidence that the abilities tapped by the tasks SDMT, PASAT and WLG are particularly sensitive to MS, and further extend this issue by showing that these abilities are likely to be more sensitive than others to the progression of the disease, as compared to HC.

Information processing speed in multiple sclerosis: Past, present, and future

BACKGROUND

Information processing speed (IPS) is a prevalent cognitive impairment in multiple sclerosis (MS).

OBJECTIVES

This review aims to summarize the methods applied to assess IPS in MS and its theoretical conceptualization. A PubMed search was performed to select articles published between 1 January 2004 and 31 December 2013, resulting in 157 articles included.

RESULTS

The majority (54%) of studies assessed IPS with heterogeneous samples (several disease courses). Studies often report controlling for presence of other neurological disorders (60.5%), age (58.6%), education (51.6%), alcohol history (47.8%), or use of steroids (39.5%). Potential confounding variables, such as recent relapses (50.3%), history of developmental disorders (19.1%), and visual problems (29.9%), were often neglected. Assessments used to study IPS were heterogeneous (ranging from simple to complex tasks) among the studies under review, with 62 different tasks used. Only 9.6% of articles defined the construct of IPS and 22.3% discussed IPS in relation to a theoretical model.

FUTURE DIRECTIONS

The challenges for the upcoming decade include clarification of the definition of IPS as well as its theoretical conceptualization and a consensus on assessment. Based on the results obtained, we propose a new theoretical model, the tri-factor model of IPS.

Reduced information processing speed as primum movens for cognitive decline in MS

Background:

Cognitive impairment affects half of the multiple sclerosis (MS) patient population and is an important contributor to patients’ daily activities. Most cognitive impairment studies in MS are, however, cross-sectional or/and focused on the early disease stages.

Objective:

We aim to assess the time course of decline of different cognitive domains.

Methods:

We collected neuropsychological data on 514 MS patients to construct Kaplan-Meier survival curves of the tests included in the Neuropsychological Screening Battery for MS (NSBMS) and the Symbol Digit Modalities Test (SDMT). Cox-proportional hazard models were constructed to examine the influence of MS onset type, age at onset, gender, depression and level of education on the time course, expressed as age or disease.

Results:

Survival curves of tests focusing on information processing speed (IPS) declined significantly faster than tests with less specific demands of IPS. Median age for pathological decline was 56.2 years (95% CI: 54.4–58.2) on the SDMT and 63.9 years (95% CI: 60–66.9) on the CLTR, a memory task.

Conclusion:

In conclusion, IPS is the cognitive domain not only most widely affected by MS but it is also the first cognitive deficit to emerge in MS.

Validating predictors of disease progression in a large cohort of primary-progressive multiple sclerosis based on a systematic literature review

BACKGROUND

New agents with neuroprotective or neuroregenerative potential might be explored in primary-progressive Multiple Sclerosis (PPMS)--the MS disease course with leading neurodegenerative pathology. Identification of patients with a high short-term risk for progression may minimize study duration and sample size. Cohort studies reported several variables as predictors of EDSS disability progression but findings were partially contradictory.

OBJECTIVE

To analyse the impact of published predictors on EDSS disease progression in a large cohort of PPMS patients.

METHODS

A systematic literature research was performed to identify predictors for disease progression in PPMS. Individual case data from the Sylvia Lawry Centre (SLC) and the Hamburg MS patient database (HAPIMS) was pooled for a retrospective validation of these predictors on the annualized EDSS change.

RESULTS

The systematic literature analysis revealed heterogeneous data from 3 prospective and 5 retrospective natural history cohort studies. Age at onset, gender, type of first symptoms and early EDSS changes were available for validation. Our pooled cohort of 597 PPMS patients (54% female) had a mean follow-up of 4.4 years and mean change of EDSS of 0.35 per year based on 2503 EDSS assessments. There was no significant association between the investigated variables and the EDSS-change.

CONCLUSION

None of the analysed variables were predictive for the disease progression measured by the annualized EDSS change. Whether PPMS is still unpredictable or our results may be due to limitations of cohort assessments or selection of predictors cannot be answered. Large systematic prospective studies with new endpoints are needed.

Symptomatic treatment and management of multiple sclerosis

The range of symptoms which occur in multiple sclerosis (MS) can have disabling functional consequences for patients and lead to significant reductions in their quality of life. MS symptoms can also interact with each other, making their management challenging. Clinical trials aimed at identifying symptomatic therapies have generally been poorly designed and have tended to be underpowered. Therefore, the evidence base for the management of MS symptoms with pharmacologic therapies is not strong and tends to rely upon open-label studies, case reports, and clinical trials with small numbers of patients and poorly validated clinical outcome measures. Recently, there has been a growing interest in the management of MS symptoms with pharmacologic treatments, and better-designed, randomized, double-blind, controlled trials have been reported. This chapter will describe the evidence base predominantly behind the various pharmacologic approaches to the management of MS symptoms, which in most, if not all, cases, requires multidisciplinary input. Drugs routinely recommended for individual symptoms and new therapies, which are currently in the development pipeline, will be reviewed. More interventional therapies related to symptoms that are refractory to pharmacotherapy will also be discussed, where relevant.

Pain and cognition in multiple sclerosis

There is a high prevalence of pain, depression, and cognitive dysfunction in patients with Multiple Sclerosis (MS). These symptoms affect daily tasks resulting in a significant reduction in quality of life. Pain and cognitive changes have been studied across various animal models of MS. In these models the onset of pain and cognitive dysfunction occur early, and do not coincide with the pattern of motor deficits. This is likely underpinned by a number of different mechanisms including changes in glutamate transmission, glial cell activation, and increased levels of pro-inflammatory cytokines. Changes in pain and cognition have been described as belonging to a cluster of symptoms and have been linked through centrally driven processes. In particular, the overactive immune response can induce a state of "sickness-like behaviours" that can influence both pain and cognition. Investigating the mechanism of inflammatory sickness behaviors in MS could lead to a better understanding of the links between pain and cognition. There are currently few effective treatments for pain and cognition dysfunction in MS. Studying the relationship between these symptoms will allow better management of both symptoms.

Processing speed versus working memory: contributions to an information-processing task in multiple sclerosis

Individuals with multiple sclerosis (MS) often experience cognitive impairments in information processing. However, the relative contributions of processing speed abilities and working memory abilities to information-processing tasks are not yet fully understood. The current study examined the extent to which processing speed and/or working memory abilities contributed to an information-processing task, the Keeping Track Task (KTT). Forty-nine individuals with MS were given tests to assess processing speed and working memory, as well as the KTT. Regression analyses indicated that in the MS group, processing speed abilities accounted for the majority of the explained variance in KTT performance. The findings suggest that processing speed plays a significant role on KTT performance in MS. Implications for cognitive rehabilitation treatments aimed at improving processing speed abilities in MS are discussed.

Cognitive change and neuroimaging following immunoablative therapy and hematopoietic stem cell transplantation in multiple sclerosis: A pilot study

BACKGROUND

Individuals with MS undergoing immunoablative therapy and hematopoietic stem cell transplantation (HSCT) show substantial decrease in brain volume over 2.4 months, presumably from chemotoxic effects, although other mechanisms have also been postulated.

OBJECTIVE

We examined whether volume loss was accompanied by a concomitant decrease in cognition. White and gray matter volumes, and the effect of stem cell dosage were considered.

METHODS

Seven individuals with rapidly progressing MS and poor prognosis underwent high dose immunosuppression and autologous HSCT. Neuropsychological testing and MRI scans were performed at baseline, 2 and 24 months post-procedure.

RESULTS

Cognitive impairment was noted at all times in most participants. Median decline of 1.39% in total brain volume was noted 2 months post-HSCT. By 24 months a further decline of 1.65% was noted. At 2 months significant decline was observed for areas of executive functioning. At 24 months almost no significant declines were noted. No significant correlations were found between cognitive decline and change in imaging variables or stem cell dosage.

CONCLUSIONS

Cognition changed in the early period following treatment but with little apparent relationship to volume changes. With temporal distance from the HSCT procedure, cognition returned to baseline levels. With the caution of a very small sample, preliminary results suggest that immunoablation and HSCT may have no lasting deleterious effects on cognition.

Difficulties in planning among patients with multiple sclerosis: a relative consequence of deficits in information processing speed

Previous studies show that MS patients take longer than healthy controls to plan their solutions to Tower of London (TOL) problems but yield conflicting results regarding the quality of their solutions. The present study evaluated performance under untimed or timed conditions to assess the possibility that differences in planning ability only occur when restrictions in solution times are imposed. MS patients (n = 39) and healthy controls (n = 43) completed a computerized version of the TOL under one of two conditions. In the untimed condition, participants were allowed as much time as needed on each problem. In the timed condition, limits were imposed on solution times and time remaining was displayed with each problem. Patients exhibited longer planning times than controls, and the disparity between groups increased with problem difficulty. Planning performance depended upon condition. In the untimed condition, patients and controls performed equally well. When solution times were restricted, however, patients solved fewer problems than controls. MS patients' planning ability is intact when permitted sufficient time to formulate the required plan. Deficiencies in planning are only evident when time is restricted, and, therefore, are more accurately considered a relative consequence of disease-related problems in information processing speed.

[Acquired and developmental Gerstmann syndrome. Illustration from a patient with multiple sclerosis]

Gerstmann's syndrome (GS) is defined by a clinical tetrad including acalculia, finger anomia, left-right disorientation and agraphia. In this article, we describe the case of a 42-year-old woman suffering from an aggressive relapsing-remitting multiple sclerosis in which a systematic neuropsychological assessment revealed Gertsmann's syndrome amongst other cognitive disturbances. Brain MRI showed a high concentration of plaques within a left subcortical parietal region that has recently been considered as a crucial node for GS appearance. However, history, taking provided information suggesting that an important part of the GS, may have been present since childhood, evoking a possible neurodevelopmental origin in this patient. This article reviews the role of the GS concept in contemporary literature, with a special attention to pathophysiological hypotheses and to precautions necessary to study such cases.

Cognition in multiple sclerosis

PURPOSE OF REVIEW

A broad overview of cognition in multiple sclerosis (MS) is provided, taking account of its impact on the lives of patients, how cognitive impairment relates to disease and magnetic resonance variables, which cognitive domains are most vulnerable, the influence of depression and fatigue and what treatment options are available.

RECENT FINDINGS

The current focus is on cognitive reserve, which seems to offer some protection from the cognitive impact of MS. There is also considerable momentum with new MRI techniques and growing interest in PET studies.

SUMMARY

Cognition in MS is a priority for patients. Although understanding of the natural history of MS cognitive deficits is reasonably well understood, treatment options require further work before precise recommendations can be made on an individual basis.

Cognitive functioning in multiple sclerosis

In this article, the nature and course of cognitive dysfunction in MS are reviewed, particularly in the context of recent advances in our understanding of the diffuse nature of neuropathology in MS, and in the context of specific factors that may confer risk or protection for the development of cognitive impairment. In addition, assessment and screening approaches of MS-related cognitive dysfunction are discussed. MS is a condition not only restricted to the adult population, and this article includes a brief description of cognition in pediatric-onset MS. Finally, promising intervention approaches to treat cognitive problems in MS are summarized.

Cognitive impairment in early stages of multiple sclerosis

Cognitive dysfunction involves 40-65% of multiple sclerosis patients and can have a great functional impact. It can be detected in all the disease phenotypes since the early stages of the disease, and tends to progress over time. Memory, complex attention, information-processing speed and executive functions are most commonly involved. The relationship between cognitive changes and magnetic resonance imaging (MRI) findings may involve changes in different areas, including white matter lesions, cortical and deep grey matter and normal appearing brain tissue on conventional MRI. The search for effective therapeutic strategies is a major undertaking, involving the use of both pharmacologic and rehabilitative approaches. Early treatment with disease-modifying drugs that can contain the disease burden in the brain seems to be highly advisable in order to prevent or delay the development of cognitive impairment.

Relationship between global cognitive decline and depressive symptoms in multiple sclerosis

Cognitive impairment and depressed mood are common symptoms in multiple sclerosis (MS), which significantly impact patients' role functioning and quality of life. Cross-sectional studies indicate a modest association between cognitive impairment and depressive symptoms in MS. Longitudinal studies show inconsistent results but provide some data indicating a relationship between increasing global cognitive decline and increasing depressive symptoms over time. Establishing whether such a relationship exists represents an important first step in understanding the temporal nature of that relationship along with any treatment implications. The current study investigated this relationship by using the adjusted difference between a demographic estimate of premorbid intellectual functioning (Barona) and a performance measure of current intellectual functioning (Shipley Institute of Living) to capture long-term global cognitive decline in MS patients. Degree of global cognitive decline was then related to a self-report measure of mood, evaluative, and vegetative depression symptoms (Chicago Multiscale Depression Inventory). Global cognitive decline accounted for 5% of the variance in mood-evaluative symptoms but none of the variance in vegetative symptoms. When groups experiencing moderate, mild, and no global cognitive decline were compared on depression symptom subscales, MS patients experiencing moderate cognitive decline reported significantly higher mood and evaluative, but not vegetative, depressive symptoms than MS patients with stable cognitive functioning.

Assessment of social cognition in patients with multiple sclerosis

We examined the capacity of patients with multiple sclerosis (MS) to attribute mental states to others and to identify cognitive abilities that subserve theory of mind (ToM). In this article, we report findings on 41 out-patients with diagnosed MS who underwent detailed neuropsychological and social-cognitive assessment. They were subdivided into a cognitively intact (n=15) and cognitively impaired (n=26) group according to their neuropsychological test results. Their results were compared with those of 20 age- and education-matched controls. MS patients with cognitive impairments were found to have more difficulties attributing mental states to others than did cognitively intact MS patients and normal controls on two ToM measures; short stories (Happé, Winner, & Brownell, 1998) and video clips (Ouellet, Bédirian, Charbonneau, & Scherzer, 2009). When attention, memory, and working memory were controlled, performance on the WAIS-III Picture Arrangement task accounted for 17.3% of the variance in performance on the video clips task. Performance on a WAIS-III index composed of Similarities and Comprehension subtests, accounted for 7.0% of the variance in performance on the short stories task. These results provide some preliminary information on the effect of MS-related cognitive deficits on the ability to attribute mental states to others.

Effects of immunomodulatory treatment with subcutaneous interferon beta-1a oncognitive decline in mildly disabled patients with relapsing—remitting multiple sclerosis

The objective of this study was to assess the effects of subcutaneous (sc) interferon beta-1a (IFNβ-1a) on cognition in mildly disabled patients with relapsing—remitting multiple sclerosis (RRMS). Patients aged 18—50 years with RRMS (McDonald criteria; Expanded Disability Status Scale score ≤4.0) were assigned IFNβ therapy at the physician’s discretion and underwent standardized magnetic resonance imaging, neurological examination and neuropsychological testing at the baseline and regular intervals for up to three years.

This analysis included 459 patients who received sc IFNβ-1a (44 mcg: n = 236; 22 mcg: n = 223; three-year follow up was available for 318 patients). The hazard ratio for cognitive impairment over three years (44 mcg versus 22 mcg) was 0.68 (95% confidence interval [CI]: 0.480—0.972), suggesting a 32% lower risk with the higher dose treatment. At year 3, the proportion of patients who were cognitively impaired increased slightly from 23.5% at the baseline to 24.8% in the IFNβ-1a 22 mcg treatment group, but remained stable at 15.2% in the IFNβ-1a 44 mcg treatment group. The proportion of patients with cognitive impairment at year 3 was significantly higher in the 22 mcg group than in the 44 mcg group (P = 0.03), although a trend was also seen at the baseline (P = 0.058). Multivariate logistic regression (corrected for baseline cognitive deficits) indicated that treatment with the higher dose of IFNβ-1a was predictive of lower cognitive impairment at three years (odds ratio: 0.51, 95% CI: 0.26—0.99) compared with the lower dose of IFNβ-1a.

These findings suggest that sc IFNβ-1a may have dose-dependent cognitive benefits in mildly disabled patients with RRMS, and may support early initiation of high-dose IFNβ-1a treatment.

Sensitivity of conventional memory tests in multiple sclerosis: comparing the Rao Brief Repeatable Neuropsychological Battery and the Minimal Assessment of Cognitive Function in MS

BACKGROUND

Cognitive impairment is common in multiple sclerosis (MS) affecting roughly 45-60% of patients. Because memory deficits have significant impact on employment, caregiver burden, and social functioning, neuropsychological (NP) assessment is often recommended. Two widely used and validated NP batteries for MS are the Rao Brief Repeatable Neuropsychological Battery (BRNB) and the Minimal Assessment of Cognitive Function in MS (MACFIMS). Although similar, these batteries differ in the specific auditory/verbal and visual/spatial memory tests employed. The relative sensitivity of these memory tests is unknown.

METHODS

The BRNB and MACFIMS have considerable overlap but different memory tests: the former includes the Selective Reminding Test (SRT) and the 10/36 Spatial Recall Test (10/36) and the latter the California Verbal Learning Test, Second Edition (CVLT2) and Brief Visuospatial Memory Test, Revised (BVMTR). In 65 patients with MS and 46 demographically matched controls, we compared the sensitivity of these tests, and secondarily their respective batteries.

RESULTS

The BRNB and MACFIMS were comparable in their overall sensitivity to disease status. Although the BVMTR showed greater discriminative validity than the 10/36, the CVLT2 and SRT were comparable in sensitivity. The SDMT was the most sensitive NP test across both batteries.

CONCLUSIONS

We conclude that the BRNB and MACFIMS have comparable sensitivity among patients with MS. The sensitivity of the auditory/verbal memory tests from these batteries is similar, but the BVMTR appears to be more sensitive than the 10/36. Clinical implications are discussed.

Rapid serial processing in patients with multiple sclerosis: the role of peripheral deficits

This study compared speed of information processing in patients with relapsing-remitting or secondary progressive multiple sclerosis (MS) and healthy controls using the Stroop Test and a Picture Naming Test (PNT). While both tests evaluated processing speed within a format calling for rapid serial processing of stimulus information, the PNT included trials designed to impose greater verbal-motor and ocular-motor challenges by using novel rather than repeated pictures and by presenting the pictures in distributed locations rather than always centered on the screen. The results confirmed that a decrease in the speed of information processing is a key feature of the cognitive impairment occurring in conjunction with MS. When this feature is evaluated with tests requiring rapid serial processing of stimulus information, the contribution of peripheral motor deficits appears to be modest.