Disability and intellectual function in multiple sclerosis patients.

Forty-eight multiple sclerosis patients were rated on the Kurtzke Disability Status Examination and tested on the Wechsler Adult Intelligence Scale. Their disability status scores, ranging from 1 to 9, with a mean of 3.98, correlated significantly only with duration of illness (r = .33, significant at the.05 level). Severity of disability was not significantly correlated with age of patient, age at onset of multiple sclerosis symptoms, Verbal IQ, Performance IQ, or Full Scale IQ. Wechsler Adult Intelligence Scale mean subtest scores ranged from average to bright normal. Scores on Performance subtests with a large motor component were lower than on Verbal subtests measuring verbal overlearned information, abstract reasoning, and vocabulary.