An electroencephalographic study of psychiatric inpatients with antipsychotic-induced tardive dyskinesia

The awake EEGs of 48 psychiatric inpatients with tardive dyskinesia were compared with those of 29 matched controls without TD. EEGs of the TD patients were as follows: 22 (45.8%) were normal EEGs; 17 (35.4%), mildly abnormal EEGs; 8 (16.7%), moderately to severely abnormal EEGs. One record was excluded for severe artifacts. The control group showed a similar incidence of EEg abnormalities. EEGs with poor occipital alpha rhythm were significantly more frequent in the TD group than the control group. The TD patients tended to have an alpha rhythm of low voltage. Other characteristics of the alpha rhythm and amounts of theta, delta and beta activity showed no significant differences between the two groups. Severity of TD had no significant influence on EEG findings. The EEG similarities of TD and Huntington's chorea were discussed, and a suggestion was made that not only the basal ganglion, but also the cerebral cortex, could be involved in development of TD.