BAEP abnormalities in tardive dyskinesia.

To evaluate brainstem dysfunction, brainstem auditory-evoked potentials (BAEPs) were recorded in 13 patients with tardive dyskinesia. Only patients under 60 years of age were included because of the spontaneous dyskinetic syndromes that frequently occur in elderly persons. Clinical assessment was performed with the Abnormal Involuntary Movement Scale (AIMS). BAEP measurements were taken in order to detect lesions in the brainstem. In 14 of 26 pathways (13 patients), abnormalities in the BAEPs were found which corresponded well to lesions found in former neuropathological reports of patients with tardive dyskinesia. The functional disturbance causing abnormal BAEPs may be an expression of structural brain changes in tardive dyskinesia patients.