Cognitive disturbances in patients with relapsing remitting multiple sclerosis.

The performance of 42 patients with relapsing remitting (RR) multiple sclerosis was compared with that of 24 age-, education-, and gender-matched control subjects on a battery of neuropsychological tests known from previous studies to be sensitive to the impairments of patients with chronic progressive (CP) multiple sclerosis. Like CP patients, RR patients exhibited deficits on tests of information-processing speed, verbal fluency, and problem solving, and on recall measures of anterograde and remote memory. Although a few patients were mildly dysnomic, the RR patients were not generally impaired on visual confrontation naming and they did not exhibit perseverative responding on verbal fluency measures. The pattern of neuropsychological deficits exhibited by RR patients closely approximates the profile observed in other subcortical dementias and does not contain the features of cortical dementia evident in some CP patients. The impairment of RR patients on cognitive tests were less severe than those observed in CP patients in our previous studies. Differences in the age of patients in the CP and RR groups did not account for group differences in the severity of cognitive impairments, but differences in disease duration or severity of disability, as well as disease course, could explain why CP patients exhibit more serious cognitive disturbances than RR patients.