The prevalence of cognitive impairment in a community survey of multiple sclerosis

The Prevalence of Cognitive Impairment in Relapsing-Remitting Multiple Sclerosis: A Systematic Review and Meta-analysis

It is increasingly recognized that cognitive symptoms are a common sequelae of relapsing-remitting multiple sclerosis and are associated with adverse functional consequences. However, estimates of cognitive impairment (CIm) prevalence vary widely. This study aimed to determine the pooled prevalence of CIm among adults with RRMS and investigate moderators of prevalence rates. Following prospective registration (PROSPERO; CRD42021281815), electronic databases (Embase, Scopus, Medline, and PsycINFO) were searched from inception until March 2023. Eligible studies reported the prevalence of CIm among adults with RRMS, as determined through standardized neuropsychological testing and defined as evidence of reduced performance across at least two cognitive domains (e.g., processing speed, attention) relative to normative samples, healthy controls, or premorbid estimates. The electronic database search yielded 8695 unique records, of which 50 met selection criteria. The pooled prevalence of cognitive impairment was 32.5% (95% confidence interval 29.3-36.0%) across 5859 participants. Mean disease duration and age were significant predictors of cognitive impairment prevalence, with samples with longer disease durations and older age reporting higher prevalence rates. Studies which administered more extensive test batteries also reported significantly higher cognitive impairment prevalence. Approximately one third of adults with RRMS experience clinical levels of CIm. This finding supports the use of routine cognitive testing to enable early detection of CIm, and to identify individuals who may benefit from additional cognitive and functional support during treatment planning.

Cognitive Relapse in Multiple Sclerosis: New Findings and Directions for Future Research

Multiple sclerosis (MS) is a chronic inflammatory, demyelinating disease of the central nervous system, often presenting with brain atrophy and cognitive impairment (CI). In the relapsing–remitting phenotype, cognitive performance is increasingly recognized to decline acutely during MS relapse, with varying degrees of recovery afterwards. Therefore, CI in MS may result from incomplete recovery from episodes of so-called “cognitive relapse”, gradual neurodegeneration, or both. Among a variety of validated measures of cognitive performance, the Symbol Digit Modalities Test (SDMT) represents the most sensitive measure of cognitive decline and is easily translated to clinical practice. In fact, cognitive relapse identified using the SDMT has been reported in clinically relapsing cohorts as well as in individuals with no other neurological signs, suggesting that routine cognitive assessment may be necessary to fully appreciate the extent of a patient’s disease activity. The aim of this narrative review is as follows: (1) to provide the historical context for neuropsychological assessment in MS, (2) to provide a summation of key studies describing the cognitive relapse phenomenon, and (3) to discuss current gaps in our knowledge and highlight avenues for future research.

Predominant domains and associated demographic and clinical characteristics in multiple sclerosis-related cognitive impairment in mildly disabled patients

Background

Cognitive impairment (CI) is a common finding in multiple sclerosis (MS); however, there is a limited information about its prevalence in mildly disabled cases. We aimed to determine the most affected domains, and also the relation between the demographic factors and cognitive outcomes in mildly disabled relapsing–remitting MS (RRMS).

Results

Ninety-one mildly disabled RRMS patients with expanded disability status scale (EDSS) < 4 and literacy level above 9 years, were recruited. Based on Minimal Assessment of Cognitive Function in MS (MACFIMS) battery, CI was observed in 19.8% of the patients while 40.60% of the patients had at least one failure in cognitive tests. The most common impaired cognitive domain was information processing speed and working memory (27.5%). There was no significant difference between men and women in terms of CI in our sample (p-values > 0.05). Disease duration (p = 0.01), EDSS (p = 0.01), and education (p < 0.01) were significantly different between CI and non-CI patients, while age (p = 0.72), sex (p = 0.50), diagnostic gap (p = 0.89), and frequency of relapses (p = 0.22), did not differ considerably.

Conclusions

RRMS patients experience some degrees of CI that may present even before the onset of remarkable physical disability; nevertheless, a higher EDSS score and longer disease duration increases the risk of CI. These findings suggest routine cognitive assessment of MS patients.

Mental Health in Multiple Sclerosis During the COVID-19 Outbreak: A Delicate Balance between Fear of Contagion and Resilience

The current study aimed at exploring the relationship between objective disability, illness perceptions, resilience, fear of COVID-19, and psychological distress (i.e., anxiety, depression, and stress) in people with multiple sclerosis (pwMS) during the second wave of the COVID-19 outbreak. A group of 122 pwMS recruited in an Italian university hospital took part in this cross-sectional monocentric study. Hierarchical multiple linear regression analyses were performed to assess the strength of the hypothesized associations. Results indicated that, differently from cognitive impairment, motor disability was positively associated with anxiety. However, accounting for subjective illness perception, such association was no longer significant. Moreover, accounting for both protective and risk factors in the models, even illness perception was no longer significant, highlighting the central role of resilience and fear of COVID-19 in explaining the negative emotional outcomes. Implications for clinical interventions and psychoeducational trainings are discussed.

The Possible Direct Correlation between Cognitive Impairment and Fear of Catching COVID-19 among Patients with Multiple Sclerosis

Objective: The prevalence of cognitive impairment in multiple sclerosis (MS) is significant and it is estimated that 40% to 70% of patients with MS suffer from this impairment. COVID-19 is also a new infectious disease. The symptoms of this disease, which include fever, shortness of breath, and cough, can be mild to severe and can even lead to death. Due to the use of immunosuppressive drugs by Patients with MS, they might be at greater risk of catching COVID-19. Thus, patients with MS may be more afraid of catching the virus. One of the important factors is the relationship between cognitive deficit and the increase in patients' fear of COVID-19. The aim of this study was to assess the relationship between fear of catching COVID-19 and cognitive impairment in patients with MS.

Method: This cross-sectional study was conducted at the MS Clinic, Sina hospital, Tehran University of Medical Sciences, Tehran, Iran. Our participants in this project were Patients with MS who were over 18 years old and had no history of other neurological and psychiatric diseases. In addition to obtaining demographic and clinical information, we measured the fear of catching the COVID 2019 via Fear of COVID-19 Scale (FCV-19S), which is 7-item questionnaire. We also used Multiple Sclerosis Neuro Psychological Screening Questionnaire (MSNQ) to assess memory and information processing speed in Patients with MS.

Results: After adjustment for age, gender, disease duration, highest level of education, MS type, and EDSS in linear regression model, as well as the MSNQ total score and fear score of catching coronavirus, the results demonstrated a significant positive correlation with P value of 0.00 and β: 0.024.

Conclusion: The present study showed a direct relationship between cognitive disorder and level of fear regarding COVID-19. Patients with more cognitive disorders were more afraid of COVID-19.

Evaluation of the cognitive benefits of intrathecal baclofen pump implantation in people with intractable multiple sclerosis related spasticity

BACKGROUND

Spasticity is a common problematic symptom in Multiple Sclerosis with over one third of patients failing first line therapies. Intrathecal baclofen is a safe and efficacious option for treatment resistant spasticity. Anecdotally patients report improved concentration/cognitive performance when switching to intrathecal baclofen (ITB) from systemic medications.

AIM

To explore whether subjects who proceed with ITB pump implantation for spasticity management and reduce oral anti-spasticity agents will have improved cognitive function.

METHODS

Subjects were admitted for trial of ITB via lumbar puncture and subsequent pump implantation. Spasticity and cognitive measures before ITB trial and 3 months post implant were recorded. Paired t-test or Wilcoxon Signed Ranks test was used for within subject change and effect sizes (Cohen's d_z) were calculated. Subgroup analysis of those on ≥2, or ≤ 1 spasticity medications at baseline was performed.

RESULTS

27 subjects with MS completed per protocol. Mean age 46 years [26 - 56], disease duration 15 years [6 - 26], RRMS = 3, SPMS = 17 and PPMS=7. The majority were on multiple spasticity medications. Spasticity scores significantly improved post pump implant. Mean ITB dose at 3 months was 143 mcg / day and 19 discontinued all other treatments for spasticity. There was no deterioration on any cognitive or mood measure. An improvement of moderate effect size was found in Backwards Digit Span (d=0.41, p=0.059) and HADS - anxiety (d=0.37, p=0.097). Fatigue Severity Scale score decreased substantially (d=0.81, p=0.005). Small improvements in Symbol Digit Modalities Test score (d=0.24) and Sustained Attention to Response Task response time (d=0.23) were non-significant. Performance on other measures did not change. Effect sizes were larger in subgroup on ≥2 oral spasticity medications at baseline, compared to the group on ≤1 medication (SDMT, d=0.42 vs d=0.07; Backwards digit span 0.45 vs 0.28; HADS-anxiety 0.39 vs 0.32; HADS-depression d=0.32 vs 0.05 and FSS, d= 1.14 vs 0.42).

CONCLUSIONS

In a pilot study exploring the impact of ITB on cognition, spasticity scores improved universally and beneficial effects on some measures of fatigue, anxiety, auditory attention and verbal working memory were found. Improvement of speed of processing in those withdrawing higher doses of oral medication was also demonstrated suggesting that switching to ITB has added cognitive and psychological benefits for people with MS.

The Expanded Disability Status Scale Score and Demographic Indexes Are Correlated with the Severity of Cognitive Impairment in Multiple Sclerosis Patients

Background and Purpose

Cognitive impairment (CI) is a common symptom of multiple sclerosis (MS). Although demographic and clinical factors contribute to MS-dependent CI, previous findings have been inconsistent. This study aimed to identify the cognitive domains that are impaired in MS patients, and to determine the impacts of the Expanded Disability Status Scale (EDSS) score and other clinical and demographic factors on them domains.

Methods

This study enrolled 115 MS patients. Cognitive performance was assessed using the Minimal Assessment of Cognitive Function in Multiple Sclerosis (MACFIMS) battery. CI severity was assessed based on the number of impaired tasks in the MACFIMS battery, with impairment in two or more tasks defined as CI cases. Correlation analysis was used to determine whether factors including current age, age at disease onset, EDSS score, disease duration, relapse rate, and education level affect the severity of CI.

Results

The scores on the Paced Auditory Serial Addition Test and Delis-Kaplan Executive Function System were the most and least affected, respectively. EDSS score (r=0.438, p<0.001), current age (r=0.393, p<0.001), and disease duration (r=0.486, p<0.001) were positively correlated with CI severity, whereas education level (r=−0.527, p<0.001) had a negative correlation with CI severity, and age at disease onset and relapse rate were not correlated with CI severity (r=0.150 and p=0.107, and r=0.052 and p=0.530, respectively). However, all variables (except EDSS score) significantly predicted CI severity in a multiple regression model (p<0.001, r=0.668).

Conclusions

Information processing speed and working memory were the most commonly affected cognitive domains in the present MS patients. CI severity had strong positive correlations with current age, EDSS score, and disease duration, and a negative correlation with education level. The relapse rate and age at disease onset were not correlated with CI severity.

The relationship between executive functions and fluid intelligence in multiple sclerosis

BACKGROUND & OBJECTIVE

Deficits in cognitive functions dependent upon the integrity of the prefrontal cortex have been described in Multiple Sclerosis (MS). In a series of studies we have shown that fluid intelligence (g) is a substantial contributor to frontal deficits and that, for some classical "executive" tasks, frontal deficits were entirely explained by g. However, for another group of frontal tasks deficits remained once g was introduced as a covariate. This second set of tests included multitasking and theory of mind tasks. In the present study, we aimed at determining the role of fluid intelligence in frontal deficits seen in patients with MS.

METHODS

A group of patients with Relapsing Remitting MS (n = 36) and a group of control subjects (n = 42) were assessed with a battery of classical executive tests (which included the Wisconsin Card Sorting Test, Verbal Fluency, and Trail Making Test B), a multitasking test, a theory of mind test and a fluid intelligence test.

RESULTS

MS patients showed significant deficits in the fluid intelligence task. We found differences between patients and control subjects in all tests except for the multitasking test. The differences in the classical executive tests became non-significant once fluid intelligence was introduced as a covariate, but differences in theory of mind remained.

CONCLUSIONS

The present results suggest that fluid intelligence can be affected in MS and that this impairment can play a role in the executive deficits described in MS.

Structured Cognitive-Motor Dual Task Training Compared to Single Mobility Training in Persons with Multiple Sclerosis, a Multicenter RCT

The aim was to compare the effectiveness of dual-task training (DTT) compared to single mobility training (SMT) on dual-task walking, mobility and cognition, in persons with Multiple Sclerosis (pwMS). Forty pwMS were randomly assigned to the DTT or SMT groups. The DTT-group performed dual-task exercises using an interactive tablet-based application, while the SMT-group received conventional walking and balance exercises. Both interventions were supervised and identical in weeks (8) and sessions (20). Nine cognitive-motor dual-task conditions were assessed at baseline, after intervention and at 4-weeks follow-up (FU). The dual-task cost (DTC), percentage change of dual-task performance compared to single-task performance, was the primary outcome. Mobility and cognition were secondarily assessed. Mixed model analyses were done with group, time and the interaction between group and time as fixed factors and participants as random factors. Significant time by group interactions were found for the digit-span walk and subtraction walk dual-task conditions, with a reduction in DTC (gait speed) for the DTT maintained at FU. Further, absolute dual-task gait speed during walking over obstacles only improved after the DTT. Significant improvements were found for both groups in various motor and cognitive measures. However, the DTT led to better dual-task walking compared to the SMT.

Estimating the prevalence of cognition and mental health among multiple sclerosis patients: A population-based cross-sectional study

BACKGROUND

Multiple sclerosis (MS) is a chronic neurological disease, considered most common autoimmune disorder of the central nervous system with dramatic impact on patient's emotional/mental well-being. Cognitive decline is acknowledged as debilitating symptom of MS. This paper aims to estimate the prevalence of cognition and mental health impairment among MS patients in Kuwait and test their association with socio-economic factors.

METHODS

Data were collected from 224 MS patients. As scales of MS quality of life inventory (MSQOLI), mental health inventory (MHI) and perceived deficit questionnaire (PDQ) were used to estimate scores for mental health and cognition, respectively. Tertiles were used to estimate prevalence and associations were tested accordingly.

RESULTS

The prevalence of cognition and mental health impairment were approximately 23.3% and 14.1%, respectively. When stratified by gender, significant difference exists in mental health impairment. When stratified by nationality, there is significant difference between Kuwaiti and Non-Kuwaiti Arabs in cognition. Poorest patients had median cognition score worse than all other income categories.

CONCLUSION

MS in Kuwait seems to have an earlier age at onset. There is significant gender difference in mental health impairment among patients. Future interventions should be directed toward women, low-income, and non-Kuwaiti-Arabs. The estimated prevalence is based on self-reported data, tertiles as cut-off points, and hence should be interpreted with caution. PDQ and MHI are MSQOLI scales used as screening tools that don't correlate well with an objective test and shouldn't replace objective measures of physical and cognitive function tests including expanded disability status scale or magnetic resonance imaging.

Pharmacological and Non-pharmacological Therapies of Cognitive Impairment in Multiple Sclerosis

Background

Cognitive impairment is one of the most important clinical features of neurodegenerative disorders including multiple sclerosis (MS). Conducted research shows that up to 65 percent of MS patients have cognitive deficits such as episodic memory, sustained attention, reduced verbal fluency; however, the cognitive MS domain is information processing speed. It is the first syndrome of cognitive dysfunction and the most widely affected in MS. Occasionally these impairments occur even before the appearance of physical symptoms.

Methods

Therefore, this review focused on the current status of our knowledge about possible methods of treatment cognitive impairment in MS patients including novel strategies. Research and online content was performed using Medline and EMBASE databases.

Results

The most recent research suggests that cognitive impairment is correlated with brain lesion volume and brain atrophy. The examination of the cognitive impairment is usually based on particular neuropsychological batteries. However, it can be not enough to make a precise diagnosis. This creates a demand to find markers that might be useful for identifying patients with risk of cognitive impairment at an early stage of the disease. Currently the most promising methods consist of neuroimaging indicators, such as diffusion tensor imaging, the magnetization transfer ratio, and N-acetyl aspartate levels. Diagnosis problems are strictly connected with treatment procedures. There are two main cognitive therapies: pharmacological (disease modifying drugs (DMD), symptomatic treatments) and non-pharmacological interventions that are focused on psychological and physical rehabilitation. Some trials have shown a positive association between physical activity and the cognitive function.

Conclusion

This article is an overview of the current state of knowledge related to cognition impairment treatment in MS. Additionally, novel strategies for cognitive impairments such as cryostimulation and other complementary methods are presented.

Short Report: Prevalence of Cognitive Impairment in Newly Diagnosed Relapsing-Remitting Multiple Sclerosis

Background

Cognitive impairment is common in multiple sclerosis (MS) and can manifest early in the disease process, sometimes as early as the first demyelinating event. However, the frequency of cognitive impairment in a newly diagnosed MS population has not been evaluated comprehensively in a clinical population. We sought to examine the prevalence of cognitive impairment in relapsing-remitting MS (RRMS) within a year of diagnosis in a clinic where cognitive testing at diagnosis is part of routine practice.

Methods

A retrospective medical record review of persons with RRMS assessed in a cognitive MS clinic identified 107 patients assessed by the Minimal Assessment of Cognitive Function in Multiple Sclerosis battery within 1 year of a confirmed RRMS diagnosis.

Results

The cohort was predominantly female (n = 82 [76.6%]) and white (n = 93 [86.9%]). Only 36 patients (33.6%) were diagnosed as having RRMS based on a second clinical event. Processing speed was the most frequently impaired domain (n = 38 [35.5%]). Only 37 patients (34.6%) were within normal limits on all cognitive domains. Regarding mood symptoms, 25 patients (23.4%) were positive for depressive symptoms; 59 (55.1%), for anxiety. Severe fatigue was correlated with a lower score on the Symbol Digit Modalities Test (SDMT) (r = -0.380, P < .001), and higher depressive scores were correlated with lower performance on the SDMT (r = -0.397, P < .001) and the Paced Auditory Serial Addition Test (r = -0.254, P = .009).

Conclusions

Cognitive impairment, specifically processing speed, and mood symptoms are frequently present in persons with newly diagnosed RRMS.

Investigating Domain-Specific Cognitive Impairment Among Patients With Multiple Sclerosis Using Touchscreen Cognitive Testing in Routine Clinical Care

Cognitive dysfunction is present in up to 70% of patients with multiple sclerosis (MS) and has been reported at all stages and in all subtypes of the disease. These deficits have been reported across a variety of cognitive domains, but are generally under-recognized and incompletely evaluated in routine clinical practice. The aim of this study was to investigate the spectrum of cognitive impairment in patients with MS presenting to a specialist MS clinic using the Cambridge Neuropsychological Test Automated Battery (CANTAB), administered on a touchscreen platform. Ninety MS patients completed computerized CANTAB tasks assessing working memory, executive function, processing speed, attention, and episodic memory. Scores were adjusted for age, sex, and level of education and classified as normal or impaired based on comparison with a large normative data pool. We also investigated the impact of clinical and demographic variables which could potentially influence cognitive performance including patient educational level (a proxy for cognitive reserve), disease status (duration, course, and severity of MS), and depression. CANTAB testing detected cognitive impairment in 40 patients (44% of the sample). The most frequently impaired domain was executive function, present in 55% of cognitively impaired individuals. Disease duration and severity were significantly associated with performance across various cognitive domains. Patients with depressive symptoms were also more likely to exhibit impaired processing speed. Results from this study confirm that cognitive impairment is common and occurs across a range of domains among MS patients attending routine clinical visits. CANTAB tasks provide a sensitive and practical approach to cognitive testing in MS patients as part of a holistic patient assessment.

Everyday memory measures in multiple sclerosis: a systematic review

Everyday memory is one of the most affected cognitive functions in multiple sclerosis (MS). Assessing everyday memory problems is crucial for monitoring the impact of memory deficits on individuals' day-to-day lives and evaluating the effectiveness of interventions that aim to improve cognitive functions. The aim of this systematic review was to identify the research literature on everyday memory measures used with people with MS, describe the types of measures used, and summarise their psychometric properties. Empirical studies of cognitive function in MS using standardised everyday memory measures were included. Online databases (MEDLINE, PsycINFO, PsycARTICLES, Embase) and Google Scholar were searched. Forty-four studies met the inclusion criteria. A total of 12 measures were identified, with varied uses and administration methods. The majority of papers did not report any psychometric properties for MS populations. The few papers that did, reported that the measures have good reliability and appear to have good face, concurrent, and ecological validity, but these need to be evaluated further. This review presents researchers and clinicians with an overview of the various everyday memory measures used in studies with people with MS, to help them choose the appropriate measure for their evaluations.

The neuropsychiatry of multiple sclerosis

Multiple sclerosis is the most common disabling neurological illness affecting young and middle-aged adults. Although attention has tended to focus mainly on its neurological manifestations, reports of the presence of neuropsychiatric symptoms date back to the writings of Charcot in 1877. This article details the neuropsychiatric sequelae of multiple sclerosis and the evidence base for available treatments.

Neuropsychiatric assessments in patients with multiple sclerosis in early phases and with low disability

BACKGROUND

In the early phases of multiple sclerosis (MS), patients exhibit slight neuropsychiatric deficits that can only be detected using reliable tools.

AIM

The present investigation aimed to examine neuropsychological performance in 35 patients with incipient MS.

PATIENTS AND METHODS

For the MS group, the inclusion criteria included time of disease <3 years and low disability. The neuropsychological battery consisted of Rey Auditory Learning Test, Controlled Oral Word Association Test, Hooper Visual Organization Test, and Symbol Digit Modalities Test (SDMT).

RESULTS

After correction for the educational level, no significant effect of MS on performance was found for all the tests except for the number of errors of the SDMT (NE-SDMT). Higher levels of education were associated with better performances in all tests, except for the NE-SDMT. MS patients made more errors than the controls.

CONCLUSION

The effect on the NE-SDMT may reflect difficulties in the ability to inhibit inadequate responses. Patients may exhibit impulsive control disorders in incipient MS, independent of their educational level.

Neuropsychological Assessment in Multiple Sclerosis

Abstract. Neuropsychological deficits in multiple sclerosis (MS) are common. Over the past decades, many different procedures have been employed in diagnosing these deficits. Even though certain aspects of cognitive performance such as information processing speed and working memory may be affected more frequently than other cognitive functions, no specific deficit profile has been established in MS. This article provides an overview of the neuropsychological diagnostic procedures in MS and allows the reader to reach an informed decision on the applicability of specific procedures and the availability of study data in the context of MS. Additionally, it makes recommendations on the compilation of both screening procedures and extensive test batteries.

Characteristics, burden of illness, and physical functioning of patients with relapsing-remitting and secondary progressive multiple sclerosis: a cross-sectional US survey

BACKGROUND

Although most patients with relapsing-remitting multiple sclerosis (RRMS) will develop secondary progressive multiple sclerosis (SPMS), little is known about the burden of multiple sclerosis by disease subtype. This study describes the burden of disease in terms of demographics, disease severity, symptoms, health care resource and disease-modifying therapy (DMT) utilization, work and activity impairment, and physical functioning of SPMS and RRMS patients.

METHODS

SPMS and RRMS patient responses from the 2012 and 2013 waves of the US National Health and Wellness Survey were evaluated to detect differences in demographics, disease severity, symptoms, and health care resource and DMT utilization. In addition, data from the Work Productivity and Activity Impairment and Short Form-36 questionnaires were analyzed.

RESULTS

SPMS patients were older than RRMS patients (mean age 55.7 vs 48.9 years; P<0.001); a lower proportion were female (56.2% with SPMS vs 71.6% with RRMS; P=0.002), and fewer SPMS than RRMS patients were employed (20.0% vs 39.7%; P<0.001). SPMS patients described their disease as more severe, reporting several neurological symptoms more frequently and higher hospitalization rates than RRMS patients. A lower percentage of SPMS than RRMS patients reported DMT use. SPMS patients had greater overall work and activity impairment than RRMS patients. After controlling for baseline characteristics, impairment in physical functioning was greater in SPMS patients.

CONCLUSION

Overall, SPMS patients had a higher burden of illness than RRMS patients, underscoring the need to treat RRMS patients early to delay disability progressing using therapies that are effective in real-world settings.

Fatigue and depression in multiple sclerosis: pharmacological and non-pharmacological interventions

Multiple sclerosis (MS) is a neuroinflammatory condition with a prominent progressive neurodegenerative facet that typically affects young- or middle-aged adults. Although physical disabilities have been in the foreground by being easier to assess, there is an increasing interest in mental disabilities and psychiatric co-morbidities, which have a disproportionally high impact on important outcome measures such as quality of life and occupational disability. In particular, cognitive impairment, depression and mental fatigue, which mutually interact with each other, seem to be of importance in this context. In recent decades, major efforts have been invested in developing more effective disease modulatory treatments. This has resulted in novel therapeutic options and awareness of the importance of early intervention. In comparison, good quality and adequately powered studies on symptomatic treatments of fatigue and psychiatric co-morbidities in MS are rare, and awareness of treatment options is much lower. We here review the existing evidence base for symptomatic treatment of fatigue and depression in MS patients. With regard to fatigue, off-label prescription of alertness improving drugs is common, in spite of all but absent evidence of efficacy. In contrast, a number of smaller studies suggest that physical exercise and fatigue management courses may have some clinical benefit. Very few studies have addressed the efficacy of antidepressants and non-pharmaceutical interventions specifically in MS patients. Therefore, treatment guidelines largely rely on data from non-MS populations. In the future, there is a strong motive to direct additional resources to the study of these important aspects of MS.

Cognitive strategies application of multiple sclerosis patients

When performing a novel task, people need to generate and apply a working strategy. The applicatio n of an appro priate working strategy enables patients with cognitive impairment (C I) to perform tasks efficiently, which in turn makes it easier to meet the challenges of daily life tasks. We investigated the strategy application abilities (SAA) of multiple sclerosis (MS) patients and compared these results with data based on healthy subjects’ performance. Seventy-six patients performed a Strategy A pplication Test (SAT) along with other cognitive tests, and completed depression, fatigue, and activity of daily living (A DL) questionnaires. O ur results indicated that 76% of the MS patients included had impaired SAA, and that this impairment was not correlated with their depression, fatigue, Expanded Disability Severity Scale (EDSS), or A DL. These findings may have important implications for the understanding of the capability of MS patients to cope with nonroutine tasks, as well as for the potential of future implementation of cognitive rehabilitation in improving the SAA of patients with MS or other cognitive disorders.

Influence of Formal Education on Cognitive Reserve in Patients with Multiple Sclerosis

The concept of cognitive reserve (CR) and its influence on cognitive impairment has attracted increasing interest. One hundred twenty-eight patients with multiple sclerosis (MS) from Southern Germany were evaluated during the years 2000 to 2012. Twenty-seven neuropsychological (NP) tests were applied regarding basic cognitive functions, attention, executive functions, visual perception and construction, memory and learning, problem solving, and language. By this retrospective approach, a comprehensive NP profile of the investigated individuals was established. An effect of timespan of formal education on CR was observed. Enrichment by reading, physical activities, and challenging vocational practices had more profound effects in patients who had undergone a shorter educational period compared to a longer educational period. In summary, our study demonstrates that the advantage of longer formal education periods, compared to shorter formal education periods, can be counterbalanced by high frequencies of reading, physical activities, and challenging vocational practices in patients with MS.

Impact of Pharmacotherapy on Cognitive Dysfunction in Patients with Multiple Sclerosis

Cognitive impairment is a common symptom of multiple sclerosis (MS), adversely impacting many spheres of daily functioning. Yet the effectiveness of pharmacological interventions for cognitive impairment in MS is unclear. Clinicians and patients alike would benefit from formal guidelines regarding effective management of cognitive symptoms. We reviewed the background on the measurement, pathophysiology and risk factors for cognitive dysfunction in MS, and then examined the published clinical trials of pharmacotherapy, including both disease-modifying treatments (DMTs) and symptom-management therapies (SMTs). Our review of DMTs revealed only a single well-designed, randomized, controlled trial where intramuscular interferon (IFN)-β1a, administered once weekly, was compared with placebo. The results showed significant benefits in terms of cognitive processing speed and memory. Less convincing but promising data have shown the potential benefits of IFN-β1b and natalizumab. The literature on SMTs is replete with placebo-controlled, single-centre studies, with a failure to replicate initially promising results. The results for SMTs such as acetylcholinesterase inhibitors and psychostimulants are mixed. Some encouraging data show promise but not to a threshold of indication for standard clinical use. Numerous methodological factors hamper research in this area. Acknowledging the lack of firm conclusions, we argue that all DMTs are likely to benefit cognition and that, if otherwise safe, SMTs with some empirical support may be attempted at the discretion of the treating clinician. We offer some guidance on the assessment and monitoring of cognitive function to inform off-license treatment of cognitive impairment in MS patients.

Can we define a rehabilitation strategy for cognitive impairment in progressive multiple sclerosis? A critical appraisal

Cognitive impairment (CI) has been shown to be severe in patients with progressive forms of multiple sclerosis (MS), and the most frequently impaired domains are sustained attention, information processing speed, memory, and executive functions. In contrast to relapsing forms of MS, where studies have shown favorable results from cognitive rehabilitation, there is a lack of data on cognitive rehabilitation in progressive forms of MS. A specific approach in assessing CI and in designing and administering rehabilitation training for patients with progressive forms of MS is needed.

Impact of the Cognitive Status on the Memory Complaints in MS Patients

Objective:

Despite the evidence of cognitive deficits in Multiple Sclerosis (MS) patients, evaluation of their cognitive integrity is often limited to the use of clinical interviews and questionnaires. However, the consensus in the literature is that these patients under- or overestimate their deficits and repercussions. The objective of this study was to clarify why some patients overestimate while others underestimate their memory deficits.

Method:

Fifty-four participants (30 MS, 24 controls) completed the Prospective and Retrospective Memory Questionnaire (PRMQ) and were tested on a battery of neuropsychological tests. Based on the test results, MS patients were categorized as having either mild or moderate/severe cognitive deficits.

Results:

The moderate/severe MS group differed from the two other groups on the Rey Auditory Verbal Learning Test (RAVLT) but did not differ from the control group on the PRMQ. Conversely, the mild MS group did not differ from the control group on the RAVLT but did report significantly more problems than this group on the PRMQ. There was no difference between the two clinical groups on the Depression Index (Beck) but there was a significant correlation (r=.409) between the depression scores and the overestimation of prospective memory problems (PRMQ).

Conclusion:

The results explain the contradiction in the literature. It is the mild group who overestimates, maybe because they are overly concerned by their deficits, whereas the cognitive impairments of the moderate/severe group lead them to underestimate and may make their self-assessment unreliable. Formal testing or information from a significant other would be advisable.

Cognitive and psychiatric comorbidities in neuromyelitis optica

OBJECTIVE

Our primary objective was to examine the neuropsychological and psychopathological profile of patients with neuromyelitis optica (NMO) and compare these to multiple sclerosis (MS) and healthy control (HC) groups. We also examined for relationships between cognitive and psychiatric variables and clinical factors including accumulated neurological disability and disease duration.

METHODS

A neuropsychological test battery was administered along with a structured psychiatric interview and quantitative measures of mood symptoms.

RESULTS

42 NMO, 42 MS and 42 HC participants were assessed. Cognitive impairments were observed in 67% of NMO patients. The prevalence and profile of cognitive impairments and lifetime prevalence of depression was similar between NMO and MS groups. However, significantly higher rates of recurrent depression and suicidality were observed in NMO patients. Correlational analyses revealed higher levels of anxiety symptoms were associated with shorter disease duration in NMO, while higher depression symptom levels were associated with higher neurological disability and poorer cognition.

CONCLUSIONS

Our results demonstrate substantial cognitive and psychiatric comorbidities in NMO patients. Similar rates of lifetime and current depression between NMO and MS appear to mask greater underlying psychiatric burden in NMO and further understandings of the course of neurobehavioural comorbidities is required to better comprehend the additional morbidity in NMO. Our data support a role for cognitive and psychiatric assessments in the comprehensive care of NMO patients.

Prevalence and incidence of cognitive impairment in multiple sclerosis: a population-based survey in Catania, Sicily

Cognitive impairment (CIm) is a frequent finding in multiple sclerosis (MS) affecting up to 65% of patients. The aim of this study was to evaluate the prevalence and incidence of CIm in a population-based cohort of MS patients identified in the city of Catania from 1995 to 2004. One-hundred and twenty-five patients experiencing the onset of MS during 1995-2004 were enrolled. Cognitive performance was assessed through the Brief Repeatable Battery (BRB) of neuropsychological tests and the Stroop word-color task (ST). CIm was defined as the failure on at least three tests involving at least two different domains. Patients without CIm at baseline were followed up after over 3 years. The most impaired tests were the Symbol Digit Modalities Test (36%) and the Paced Auditory Serial Addition Test 3 (35%). At baseline the prevalence of CIm was 44% (95% CI 35.2-53.1). An almost sixfold increased risk of developing CIm was found among MS patients aged 40 and above at the time of the NPS examination (OR 5.84; 95% CI 2.57-13.2; p value <0.0001) and a threefold increased risk for patients with an EDSS score >3 (OR 3.51; 95% CI 1.30-9.46, p value 0.01). At the follow-up out of the 70 MS patients without CIm at baseline evaluation, 26 (37.1 %) developed CIm. The total person-years at risk was 269 person-years giving an incidence rate of CIm of 96.6/1,000 person-year (95% CI 57.3-128.7). The overall prevalence of CIm in MS is 44% and the incidence after 4 years is 37.1%. CIm affects more frequently patients older than 40 years and with a higher EDSS score.

Perceived cognitive decline in multiple sclerosis impacts quality of life independently of depression

Background/Aim. The aim of this study is to examine the effects of perceived cognitive dysfunction and of depression, on self-reported QoL, in a Greek population sample of MS patients. Methods. One hundred outpatients diagnosed with MS completed the Short-Form-36 Health Survey (SF-36), as well as the Perceived Deficits Questionnaire (PDQ) and the Depression subscale of the Mental Health Inventory (MHI), as part of a clinical evaluation which included the Expanded Disability Status Scale (EDSS) estimation. Multiple linear regression was conducted to determine the best linear combination of age, gender, education, EDSS, depression, attention/concentration, retrospective memory, prospective memory, and planning/organization, for predicting QoL scores. Results. In the multivariate regression analysis models, EDSS (P < 0.05), depression (P < 0.001), perceived planning/organization (P < 0.05), and perceived retrospective memory dysfunction (P < 0.05) independently predict quality of life scores. Age, sex, education level, and perceived attention/concentration dysfunction, as well as perceived prospective memory dysfunction, do not independently predict quality of life scores. Conclusions. Perceived planning/organization impairment and perceived retrospective memory impairment in MS patients predict QoL independently of the severity of disease and the severity of depression and therefore should be considered in the assessment of patient health status as well as in the design of treatment interventions and rehabilitation.

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.

The Symbol Digit Modalities Test as sentinel test for cognitive impairment in multiple sclerosis

BACKGROUND AND PURPOSE

Cognitive impairment (CI) is found in about half of the multiple sclerosis (MS) population and is an important contributor to employment status and social functioning. CI is encountered in all disease stages and correlates only moderately with disease duration or Expanded Disability Status Scale scores. Most present neuropsychological test batteries are time-demanding and expensive. The Symbol Digit Modalities Test (SDMT) has been suggested as a screening tool for CI in MS. In this paper, we aim to assess the performance of the SDMT in predicting the outcome of an extensive battery.

METHODS

Neuropsychological test results from 359 patients were assessed in a multidisciplinary MS center (National MS Center Melsbroek, Belgium). Using receiver operating characteristic curves, the performance of the SDMT in predicting the general cognitive outcome of the extensive Neuropsychological Screening Battery for MS (NSBMS) could be assessed. The performance of the SDMT was assessed for different levels of CI and compared with other cognitive tests. Finally, useful covariates were included in a logistic regression model.

RESULTS

At a specificity of 0.60 a high sensitivity (0.91) was obtained indicating the potential of the SDMT as a sentinel test for CI in MS. The SDMT outperformed the individual tests included in the NSBMS, used as benchmark. As the logistic regression model did not result in a relevant improvement, it is concluded that most clinical variables influence both the SDMT and the NSBMS in a similar way. Excluding patients with possible practice effects, an optimal cutoff of 40 was found for the SDMT.

CONCLUSION

As the SDMT is an easy, low-cost and fast test, this result may help to detect CI in everyday clinical practice.

Modeling of cognitive impairment by disease duration in multiple sclerosis: a cross-sectional study

BACKGROUND/AIMS

Large-scale population studies measuring rates and dynamics of cognitive decline in multiple sclerosis (MS) are lacking. In the current cross-sectional study we evaluated the patterns of cognitive impairment in MS patients with disease duration of up to 30 years.

METHODS

1,500 patients with MS were assessed by a computerized cognitive battery measuring verbal and non-verbal memory, executive function, visual spatial perception, verbal function, attention, information processing speed and motor skills. Cognitive impairment was defined as below one standard deviation (SD) and severe cognitive impairment as below 2SD for age and education matched healthy population norms.

RESULTS

Cognitive performance in our cohort was poorer than healthy population norms. The most frequently impaired domains were information processing speed and executive function. MS patients with secondary-progressive disease course performed poorly compared with clinically isolated syndrome, relapsing-remitting and primary progressive MS patients. By the fifth year from disease onset, 20.9% of patients performed below the 1SD cutoff for impairment, p=0.005, and 6.0% performed below the 2SD cutoff for severe cognitive impairment, p=0.002. By 10 years from onset 29.3% and 9.0% of patients performed below the 1SD and 2SD cutoffs, respectively, p=0.0001. Regression modeling suggested that cognitive impairment may precede MS onset by 1.2 years.

CONCLUSIONS

The rates of cognitive impairment in this large sample of MS patients were lower than previously reported and severe cognitive impairment was evident only in a relatively small group of patients. Cognitive impairment differed significantly from expected normal distribution only at five years from onset, suggesting the existence of a therapeutic window during which patients may benefit from interventions to maintain cognitive health.

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.

Prospective memory, emotional valence, and multiple sclerosis

Cognitive impairments in multiple sclerosis (MS) extend to tasks demanding prospective memory (PM): remembering to perform an intended act during ongoing activity. This study investigated whether emotional content influenced the effects of MS on PM, following evidence that emotional valence can influence other aspects of memory. Thirty participants with MS were compared to 30 controls on a PM task, Virtual Week, in which emotion was manipulated. People with MS showed a consistent deficit in PM performance across manipulations of task and valence. Results indicated that emotionally positive tasks improved the PM performance of MS participants, with implications for rehabilitation.

Multiple Sclerosis-Related Dementia: Relatively Rare and Often Misunderstood

MS-related dementia is an under-recognised and misunderstood aspect of MS. It is relatively rare, occurring in approximately 10% of people with MS, while cognitive impairment in general occurs in 43% or more of people with MS. MS-related dementia is hard to detect on the basis of short social interactions or clinical interviews alone. There are very few clinically relevant scientific articles on this topic to help guide the management and support of people with MS-related dementia. This article was written in a preliminary attempt to address this problem: to describe the clinical presentation and characteristics of MS-related dementia, to alert health professionals to the sensitivities surrounding the use of dementia terminology within the MS community, and to outline the limited nature of the information, advice and support resources currently available in Australia for these middle-aged people with dementia.

A Review of Virtual Week for Prospective Memory Assessment: Clinical Implications

It is now recognised that prospective memory (PM) failures are commonly observed in clinical groups, and have important implications for functional independence. However, well-validated measures of PM have traditionally been lacking, making this construct difficult to assess in clinical practice. Rendell and Craik's (2000) Virtual Week measure was developed as an indicator of PM, and has been shown to have good psychometric properties and be sensitive to the effects of normal and abnormal adult ageing, as well as various forms of pathology. In this article, an overview of Virtual Week's characteristics is presented, and the literature relating to use of this measure in various populations reviewed. The potential implications of the development of a new computerised version of Virtual Week for clinical practice are discussed.

Does cognitive impairment affect rehabilitation outcome?

OBJECTIVES

To assess how cognitive impairment affects rehabilitation outcomes and to determine whether individual benefit regardless of cognition.

DESIGN

Prospective open observational study.

SETTING

Two rehabilitation wards admitting older adults after admissions with medical or surgical problems.

PARTICIPANTS

Two hundred forty-one individuals admitted to two rehabilitation wards, 144 female, mean age 84.4 ± 7.3 (range: 59-103).

MEASUREMENTS

The Mini-Mental State Examination (MMSE) was administered, and participants were categorized into four groups: cognitively intact (MMSE score: 27-30), mildly impaired (MMSE score: 21-26), moderately impaired (MMSE score: 11-20), and severely impaired (MMSE score: 0-10). Barthel activity of daily living score was calculated on admission, at 2 and 6 weeks (if appropriate), and at discharge to assess level of independence and improvement or deterioration in function. Information relating to mortality, discharge destination, and length of stay was also collected.

RESULTS

After adjusting for comorbidities and age, all four groups showed improvement in Barthel score from admission to discharge. This improvement was highly significant (P = .005) in participants with normal cognition and mild to moderate impairment. Severely impaired participants also made significant improvement (P = .01). Length of stay was significantly longer for participants with lower cognitive scores. Discharge of 50% of participants occurred by 26, 28, 38, and 47 days for Groups 1 to 4, respectively (P = .001). Higher rates of institutionalization and mortality (P = .02) were associated with lower MMSE score.

CONCLUSION

All participants improved functionally regardless of cognition. Likelihood of institutionalization, mortality, length of stay, and adverse incidents was higher with lower MMSE scores.

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.

Evolving expectations around early management of multiple sclerosis

Multiple sclerosis is a progressive inflammatory disease of the central nervous system. With prevention or at least delay of disease progression as a key target in the management of multiple sclerosis, current opinion on treatment encourages early intervention with well-tolerated disease-modifying treatments in order to optimize long-term clinical outcomes. Patients presenting with a clinically isolated syndrome (CIS) may progress to clinically definite multiple sclerosis, and clinical trials have demonstrated that early treatment with interferon beta can reduce the conversion rate. Cognitive impairment may already be present in patients with CISs. Today there is evolving evidence that cognitive impairment may be relevant for prognosis and that early treatment with interferon beta may also have a protective effect on the cognitive function. As an accumulation of neuronal loss is now considered to underlie the development of persistent disability in multiple sclerosis, it is crucial that treatment can protect against neuronal damage. In addition to its anti-inflammatory activity, interferon beta may have direct and indirect neuroprotective effects, and several studies have explored the role of interferon beta in regulating neuroprotective factors. With over 15 years of clinical experience as evidence, the long-term safety and efficacy of interferon beta treatment is unquestionable. Results from the CIS studies have demonstrated the high percentage of patients converting to clinically definite multiple sclerosis without treatment and the short- and long-term benefits of an early use of disease-modifying treatments. These findings support starting disease-modifying treatment as soon as the diagnosis of MS is reasonably formulated.

Cognitive decline in multiple sclerosis: impact of topographic lesion distribution on differential cognitive deficit patterns

Background: Multiple sclerosis (MS) is often accompanied by cognitive dysfunction. A negative correlation between cerebral lesion load and atrophy and cognitive performance has been pointed out almost consistently. Further, the distribution of lesions might be critical for the emergence of specific patterns of cognitive deficits.

Objective: The current study evaluated the significance of total lesion area (TLA) and central atrophy for the prediction of general cognitive dysfunction and tested for a correspondence between lesion topography and specific cognitive deficit patterns.

Methods: Thirty-seven patients with MS underwent neuropsychological assessment and magnetic resonance imaging. Lesion burden and central atrophy were quantified. Patients were classified into three groups by means of individual lesion topography (punctiform lesions/periventricular lesions/confluencing lesions in both periventricular and extra-periventricular regions).

Results: TLA was significantly related to 7 cognitive variables, whereas third ventricle width was significantly associated with 20 cognitive parameters. The three groups differed significantly in their performances on tasks concerning alertness, mental speed, and memory function.

Conclusion: Third ventricle width as a straight-forward measure of central atrophy proved to be of substantial predictive value for cognitive dysfunction, whereas total lesion load played only a minor role. Periventricular located lesions were significantly related to decreased psychomotor speed, whereas equally distributed cerebral lesion load did not. These findings support the idea that periventricular lesions have a determinant impact on cognition in patients with MS.

A review of disease-modifying therapies for MS: maximizing adherence and minimizing adverse events

BACKGROUND

In a chronic disabling disorder such as multiple sclerosis (MS), adherence to treatment is of critical importance in maximizing benefits of therapy over the long term. Adverse events (AEs) are often cited by patients who discontinue therapy.

METHODS

Databases including Medline, CINAHL, and International Pharmaceutical Abstracts were searched for literature pertaining to adherence and AEs in MS published between January 1970 and August 2008. Clinical studies and case reports of AEs were included, as were papers that outlined factors that influence adherence. An advisory board with extensive experience in managing patients with MS developed guidelines to assist healthcare providers in maximizing adherence to disease-modifying therapy.

DISCUSSION

Internally based factors such as self-image, and externally based factors such as AEs, may influence patients' willingness and ability to adhere to therapy. Management of AEs associated with disease-modifying therapies and other therapies is reviewed, including intramuscular and subcutaneous interferon beta (IFNbeta)-1a, IFNbeta-1b, glatiramer acetate, natalizumab, methylprednisolone, mitoxantrone, cyclophosphamide, methotrexate, azathioprine, and intravenous immunoglobulin.

CONCLUSIONS

Effective management of MS is an ongoing, dynamic process that can enhance patients' adherence to therapy. Healthcare practitioners may address factors influencing adherence among patients with MS by managing treatment expectations, maintaining good communication with the patient, and managing AEs of treatment. Although the guidelines proposed herein originate from a single advisory board, it seems clear that by addressing patient concerns, healthcare practitioners can work with patients to enhance their ability to continue to adhere to their therapies and thereby gain the benefits of their treatment over the long term.

Psychopathology in multiple sclerosis: diagnosis, prevalence and treatment

Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system. Demyelinization of nerve fibres not only affects the motor and sensory systems functionally, but may also cause psychopathological signs and symptoms. In addition to the psychiatric manifestations of MS, many patients have reactive psychological problems that are often hard to distinguish from the 'organic' causation of psychopathology. In any event, psychiatric comorbidity in MS deserves greater clinical attention than has been previously paid, because the presence of psychopathology may have deleterious effects on the disease process and impair coping with disability.

A salmon based diet protects mice from behavioural changes in the cuprizone model for demyelination

BACKGROUND & AIMS

Although many patients with multiple sclerosis (MS) use special diets, the data available at present are insufficient to assess any potential benefit of diet modification. Cuprizone induced demyelination is a commonly used animal model for demyelination in the central nervous system.

METHODS

The present study was designed to analyse behaviour and activity due to demyelination in mice fed with 0.2% cuprizone on three different diets. The diets consisted of (1) salmon fillets rich in marine n-3 polyunsaturated fatty acids (PUFAs), (2) cod liver oil rich in marine n-3 PUFAs, or (3) a control diet containing soybean oil rich in n-6 PUFAs. After 5 weeks of continuous cuprizone treatment, animal activity was assessed with the elevated plus maze (EPM) test. After 6 weeks the brains were fixated in paraformaldehyde and stained with luxol fast blue (LFB).

RESULTS

There was significantly less demyelination in the salmon-cuprizone group than in the two other cuprizone-treatment groups (P<0.0005). The salmon-cuprizone mice had less weight loss (P<0.001) and showed more visits in both open and closed arms of the elevated plus maze than the other cuprizone-treated groups (P<0.0001). In addition they had more entries in the open arms than both the cod liver oil-cuprizone (P<0.02) and the soybean oil-cuprizone-treated mice (P<0.0001).

CONCLUSIONS

A diet containing salmon seems to protect against behavioural changes induced by demyelination in the cuprizone model, indicating that a fish diet could have a protective effect in demyelinating diseases.

The cuprizone model for demyelination

BACKGROUND

Important advances in multiple sclerosis (MS) research have been made as a direct or indirect result of experiments in animal models for the disease, although MS is a disease only affecting humans. The cuprizone model is a model for toxic demyelination. In this model, young mice are fed with the copper chelator cuprizone, leading to oligodendrocyte death and a subsequent reversible demyelination. Spontaneous remyelination can be seen as early as 4 days after withdrawal of cuprizone.

MATERIALS AND METHODS

This article reviews previous research on this model and discusses the potential of the model for future application in MS research.

DISCUSSION

The cuprizone model correlates with newer histopathological data in MS and is a valuable tool for studies on de- and remyelination. The use of the C57BL/6 strain offers the potential for future studies on transgene and knockout mice.

Do cognitively impaired patients benefit from rehabilitation?

Rehabilitation in broad terms is a process aimed at restoring a person's functional capacity particularly in relation to activities of daily living. Studies have shown that hospitalization of older patients is a major risk factor for an often irreversible decline in function, and that functional decline from baseline occurs as early as day two of admission. Rehabilitation is therefore often required for older patients following an admission to an acute hospital. Older patients admitted for rehabilitation are more likely to be functionally impaired and are more medically complex than younger patients.