The metabolic topography of idiopathic torsion dystonia

Summary We used [18F]fluorodeoxyglucose (FDG) and PET with a statistical model of regional metabolic covariation to study brain topographic organization in idiopathic torsion dystonia (ITD). We studied 11 patients with predominantly right-sided ITD and 11 age-matched controls, and measured global, regional cerebral and normalized metabolic rates for glucose (GMR, rCMRGlc, rCMRGlc/GMR). The Scaled Subprofile Model was applied to the combined rCMRGlc dataset to identify topographic covariance profiles associated with ITD. We found that global and regional metabolic rates were normal in ITD. The SSM analysis of the combined groups of ITD patients and normals revealed a significant topographic profile characterized by relative bilateral increases in the metabolic activity of the lateral frontal and paracentral cortices, associated with relative covariate hypermetabolism of the contralateral lentiform nucleus, pons and midbrain. Subject scores for this profile correlated significantly with Fahn-Marsden disease severity ratings (r= 0.67, P