Hemiparkinsonism as a late complication of hemiatrophy: a new syndrome.

Four men with evidence of hemiatrophy resulting from early-life hemispheral injury developed unilateral hemiparkinsonism on the side of the hemiatrophy. The parkinsonism began in the fourth decade and has remained unilateral for 5 to 35 years. In all four patients, the parkinsonism was slowly progressive, but the clinical response to levodopa was minimal, suggesting that the parkinsonism might have a postsynaptic striatal component. The clinical similarities of these four patients suggest that this is a distinct syndrome in which hemiparkinsonism is a late sequela of hemiatrophy. Identification of this syndrome has prognostic significance, because it seems to have a stereotyped course, remaining unilateral and only slowly progressive.