Left ear suppression on verbal dichotic tests in patients with multiple sclerosis.

Verbal dichotic listening tests employing nonsense consonant-vowel stimulus pairs were administered to 11 right-handed patients with chronic multiple sclerosis and to 10 right-handed normal controls. A highly significant reduction of left-ear scores was found in the multiple sclerosis group. We propose that the basis for this finding is a disconnection of the auditory callosal pathway and that dichotic listening tests may be of value in detecting the presence of lesions of the deep white matter of the cerebral hemispheres in multiple sclerosis.