Computerized tomography in tardive dyskinesia. Evidence of structural abnormalities in the basal ganglia system.

Twenty-nine patients with moderate to severe tardive dyskinesia (TD) and 29 age- and sex-matched controls (C) with long-term neuroleptic therapy comparable to that of the patients were all examined using computerized tomography. Significant differences were found between the two groups in the width of the third ventricle (TD greater than C), the bicaudate distance (TD greater than C), the computed area of the head of the caudate nucleus (TD less than C), and the area of the lenticular nucleus (TD less than C). No significant differences were established in the ventricular or cella media indices. These results suggest that structural abnormalities, primarily in the basal ganglia system, are present in TD patients. Psychological testing with the Benton visual retention test also showed significant differences with regard to cerebro-organic functional impairment among TD patients.