Rehabilitation for cognitive dysfunction in people with multiple sclerosis

This is an update of the Cochrane review 'Neuropsychological rehabilitation for multiple sclerosis' (first published in The Cochrane Library 2011, Issue 11).

Demyelinating disease is any condition that results in damage to the protecting covering (myelin sheath) that surrounds nerve fibers in brain and spinal cord. Multiple sclerosis (MS) has used to be regarded simply as a demyelinating disease, however recent research has shown that widespread damage to neurons (nerve cells) and grey matter changes are central features of MS. This has emphasised cognitive dysfunction, like deficits in memory or attention, as being one of the major symptoms of the disease. Cognitive deficits are common in MS, occurring in about 50% to 60% of patients. These deficits can have a multidimensional impact on patients' activities of daily living and should be taken into account in their treatment and rehabilitation. Neuropsychological rehabilitation aims to 1) reduce cognitive deficits, 2) reduce the harmful effects of cognitive impairments and 3) support patients' awareness and ability to take cognitive impairments into account in daily living.

The aim of this review was to evaluate the effects of cognitive (neuropsychological) rehabilitation in MS. We did this by considering the effects of rehabilitation on cognitive test performance and everyday cognitive performance, as well as on depression, fatigue, personality/behaviour disturbances, anxiety and quality of life.

Twenty relevant studies comprising a total of 986 participants (966 MS participants and 20 healthy controls) were identified and included in this review. Low-level evidence was found that neuropsychological rehabilitation reduces cognitive symptoms in MS. However, when analysed individually, 18 out of the 20 studies showed positive effects. Cognitive training was found to improve memory span and working memory. Cognitive training combined with other neuropsychological rehabilitation methods was found to improve attention, immediate verbal memory and delayed memory.

It is worth noting that the small numbers of patients in the studies and some methodological weaknesses reduce the level of the evidence. To further strengthen the evidence well-designed, high-quality studies are needed. 

Authors' conclusions: 

This review found low-level evidence for positive effects of neuropsychological rehabilitation in MS. The interventions and outcome measures included in the review were heterogeneous, which limited the comparability of the studies. New trials may therefore change the strength and direction of the evidence.

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Background: 

This is an update of the Cochrane review 'Neuropsychological rehabilitation for multiple sclerosis' (first published in The Cochrane Library 2011, Issue 11).

Cognitive deficits are a common manifestation of multiple sclerosis (MS) and have a significant effect on the patient's quality of life. Alleviation of the harmful effects caused by these deficits should be a major goal of MS research and practice. 

Objectives: 

To assess the effects of neuropsychological/cognitive rehabilitation on health-related factors, such as cognitive performance and emotional well-being in patients with MS.

Search strategy: 

The Cochrane Multiple Sclerosis and Rare Diseases of the Central Nervous System Group Trials Search Co-ordinator searched their Specialised Register which, among other sources, contains trials from CENTRAL (The Cochrane Library 2013, Issue 2), MEDLINE, EMBASE, CINAHL, LILACS, PEDro and clinical trials registries (28 May 2013). We contacted authors of the studies for additional information.

Selection criteria: 

Randomised controlled trials (RCTs) and quasi-randomised trials evaluating the effects of neuropsychological rehabilitation in MS compared to other interventions or no intervention.

Data collection and analysis: 

Two review authors individually judged the eligibility of the included studies, assessed risk of bias and extracted data. We combined results quantitatively in meta-analyses according to the intervention type: 1) cognitive training and 2) cognitive training combined with other neuropsychological rehabilitation methods.

Main results: 

Twenty studies (986 participants; 966 MS participants and 20 healthy controls) fulfilled the inclusion criteria. The mean age of the participants was 44.6 years, mean length of education was 12.3 years and 70% of the participants were women. Most of the participants had a relapsing-remitting course of disease. The mean Expanded Disability Status Scale score was 3.2 and the mean duration of disease was 14.0 years.

On the basis of these studies, we found low-level evidence that neuropsychological rehabilitation reduces cognitive symptoms in MS. Cognitive training was found to improve memory span (standardised mean difference (SMD) 0.54, 95% confidence interval (CI) 0.20 to 0.88, P = 0.002) and working memory (SMD 0.33, 95% CI 0.09 to 0.57, P = 0.006). Cognitive training combined with other neuropsychological rehabilitation methods was found to improve attention (SMD 0.15, 95% CI 0.01 to 0.28, P = 0.03), immediate verbal memory (SMD 0.31, 95% CI 0.08 to 0.54, P = 0.008) and delayed memory (SMD 0.22, 95% CI 0.02 to 0.42, P = 0.03). There was no evidence of an effect of neuropsychological rehabilitation on emotional functions.

The overall quality, as well as the comparability of the included studies, was relatively low due to methodological limitations and heterogeneity of interventions and outcome measures. Although most of the pooled results in the meta-analyses yielded no significant findings, 18 of the 20 studies showed some evidence of positive effects when the studies were individually analysed.