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

Prospective memory in multiple sclerosis

There is considerable evidence that multiple sclerosis (MS) is associated with impaired retrospective memory. However, although preliminary evidence suggests that prospective memory is also affected by the disorder, the degree and nature of the impairment remains to be clarified. Twenty participants with MS were compared with 20 matched controls on Virtual Week, a measure of prospective memory that closely represents the types of prospective memory tasks that actually occur in everyday life, and provides an opportunity to investigate the different sorts of prospective memory failures that occur. The results indicated that irrespective of the specific prospective memory task demands, MS participants' performance was significantly impaired relative to controls. MS deficits could not be attributed to problems with retrospective memory because MS participants in the present study did not differ significantly from controls on measures of long- and short-term memory, and significant impairment was observed on a prospective memory task, which imposed only minimal demands on retrospective memory. These results therefore suggest that individuals with MS may experience general difficulties with prospective memory. The practical and theoretical implications of these findings are discussed