The impact of dysexecutive and metacognitive impairments on neurorehabilitation outcome in multiple sclerosis

One of the most important aims of rehabilitation for patients with multiple sclerosis (MS) is to reduce their levels of disability and handicap. Despite clinical awareness that cognitive impairments are a common feature in the clinical presentation of MS and that specific deficits (especially dysexecutive syndrome) can impede rehabilitation success, there has been a dearth of empirical research into the impact of these cognitive impairments on rehabilitation outcome. This thesis set out to further characterise findings of both dysexecutive and metacognitive impairments m MS and how they might impact on neurorehabilitation outcome m MS. 22 participants with clinically probable MS were assessed on a cognitive batten', which included tests of executive function. In addition, to assess participants insight into their executive test abilities, they were asked to rate their performance on each of the executive tests on a five-point scale. MS participants also completed a questionnaire about their dysexecutive problems in everyday life. Thirty matched healthy controls also completed the cognitive battery and the dysexecutive questionnaire. Relatives of both patients and controls rated participants dysexecutive performance, which was used to assess participants degree of insight into everyday executive function. Rehabilitation outcome was monitored using the Functional Independence Measure (FIM) (motor and cognitive) and the Expanded Disability Status Scale (EDSS). The MS participants were found to be weaker on the majority of dysexecutive tests, particularly on measures of rule learning and response suppression, compared to controls. Significant correlations were observed for the MS groups evaluations of recent executive test performance but not for the control group. Only one measure (Hayling Test A, a sentence completion task) predicted rehabilitation outcome (FIM cognitive gain). The findings highlight the subtlety of insight and dysexecutive difficulties to the cognitive profile in MS and confirm previous findings of the importance of verbal skills to neurorehabilitation outcome.