A comparison of two iatrogenic dyskinesias.

The authors compared the regions of motor involvement in levodopa-induced dyskinesia and neuroleptic-induced tardive dyskinesia. Significantly more patients with tardive dyskinesia than parkinsonian patients with levodopa-induced dyskinesia had lip and tongue movements. Patients with tardive dyskinesia had significantly higher mean AIMS scores in the orofacial region than parkinsonian patients with levodopa-induced dyskinesia. More patients with levodopa-induced dyskinesia than those with tardive dyskinesia demonstrated hyperkinesia in the lower extremities. Limb and truncal movements in levodopa-induced dyskinesia were worse in patients with more severe parkinsonism and correlated positively with the length of Parkinson's disease. These findings suggest that these dyskinesias may involve different pathophysiological mechanisms.