Neuropsychological assessment in multiple sclerosis: methodological issues and concerns.

A brief overview of research findings in five key areas pertaining to the study of neuropsychological aspects of multiple sclerosis is presented. The areas covered are: (1) general and specific cognitive deficits (2) prevalence of these deficits (3) attempts to correlate these deficits with clinicopathological features (4) attempts to investigate the relationship between deficits and abnormalities detected on magnetic resonance scanning and (5) longitudinal studies of cognitive deficits and MS. Based on this review, methodological issues that continue to hinder comparison between research reports, and across research centres, are outlined. Problem areas identified are (1) patient selection (2) selection of control subjects (3) lack of consensus regarding test selection (4) problems with statistical procedures (5) the relationship between depression and cognition (6) problems with measuring disability and MR abnormalities and (7) lack of longitudinal data.