Pharmacologic characteristics of Meige dystonia: differentiation from tardive dyskinesia.

Idiopathic orofacial dyskinesia, also called Brueghel's syndrome, blepharospasm-oromandibular dystonia, and Meige dystonia, is characterized by involuntary facial movements. Since this disorder can be difficult to distinguish from tardive dyskinesia, we have generated a neuropharmacologic profile of Meige dystonia. Symptoms were improved by antagonists of both dopamine and acetylcholine and worsened by the cholinergic agonist physostigmine, consistent with a hypothesis of relative excess in both dopamine and acetylcholine neuronal activities. Since tardive dyskinesia is hypothesized to be characterized by dopamine excess and acetylcholine deficiency, a physostigmine infusion may help differentiate these two disorders by exacerbating Meige dystonia but improving tardive dyskinesia.