Regional impairment of cerebral oxidative metabolism in Parkinson's disease.

Twenty-two patients affected by idiopathic Parkinsonism were studied using the oxygen-15 inhalation technique. The production of labelled metabolic water was found to be decreased in the parietal cerebral cortex, indicating an impairment in oxidative metabolism. This metabolic defect was localised mainly to the parietal cortex of the affected hemispheres; in non-affected hemispheres of patients presenting with unilateral Parkinsonism, the uptake was normal. In contrast, regional blood flow was not significantly altered. It is possible that this metabolic impairment is caused by chronic deafferentation.