Cognitive function in multiple sclerosis and its relation to functional abilities.

The performance of patients with multiple sclerosis (MS) on selected neuropsychologic tests was examined to ascertain the applicability of such examinations to diagnosis. Twenty-four patients with definite or probable MS, and sixteen age- and education-matched control subjects were given a battery of tests to assess intellectual functions. The results indicate that the MS patients had cognitive impairment. Severity of disability was not significantly correlated with cognitive impairment. Impaired cognitive functioning, which is often not detected through routine examination, may occur in the disease. These deficits may represent manifestations of otherwise undetectable plaques in the subcortical white matter.