Cognitive impairment, clinic forms and progression in multiple sclerosis

Introduction. Multiple sclerosis-related cognitive impairment is an important clinical dimension of the disease by virtue of its prevalence and its functional significance. It is directly related to cerebral multiple sclerosis pathology, but relatively independent of physical impairment. Development. Thus, the assessment of neuropsychologic outcomes complements the assessment of physical outcomes in multiple sclerosis clinical trials. Neuropsychologic measures fulfill most of the criteria identified for all optimal multiple sclerosis clinical outcome measure. Major drawbacks to their current use in assessing clinical trial outcomes are the heterogeneity inherent in neuropsychological test performance (both cross-sectionally and longitudinally), and limitations in our knowledge about the evolution of multiple sclerosis-related cognitive impairment and the psychometric properties of specific measures over time. As this point in time, we cannot identify the single 'best' measure for assessing neuropsychologic change in multiple sclerosis patients, and we cannot specify what constitutes clinically significant change. Analyses of neuropsychologic data from recently completed trials will soon provide an empirical basis for selecting measures to use in future multiple sclerosis clinical trials and specifying criteria for clinically significant change on these measures.