Dystonic foot response of Parkinsonism.

One third of a patient population with idiopathic parkinsonism was found to suffer from debilitating, painful dystonic movements of the lower extremities. The prevalence of this involuntary movement disorder was found to be positively correlated with the duration of dopaminergic treatment, but it also occurred occasionally in untreated persons. We suggest that the "dystonic foot response of parkinsonism" is a distinct clinical entity that has no localizing value in frontal lobe disorders and is associated with extrapyramidal disease. This disorder, though exacerbated by dopaminergic therapy, also differs from well-accepted dopaminergic side-effects and does not predictably respond to manipulation of antiparkinsonian medications. Although the precise pathophysiology of this movement disorder is unknown, its response to baclofen therapy suggests that neurotransmitter systems other than cholinergic or dopaminergic ones may be implicated.