[Involuntary movements as a complication of treatment of extrapyramidal disorders with L-dopa]

The frequency of dyskinesias connected with L-DOPA treatment of certain extrapyramidal system diseases was studied. Among 111 studied patients with Parkinson's disease drug-induced dyskinesias were observed in 56 cases (that is 50% of the treated patients) while in the group of other extrapyramidal system diseases (torsion dystonia, Hallervorden-Spatz disease, Huntington's chorea with increased muscular tonus) they were observed in only 8 cases (of 73 treated ones - about 11%). Two groups of patients with Parkinson's disease were isolated - differing in the susceptibility to dyskinesia development: those susceptible to dyskinesia which developed nearly immediately after starting treatment, and those non-susceptible, in whom dyskinesia appeared only after years of treatment. The pathomechanism of drug-induced dyskinesia development in these groups is discussed.