Basal ganglia and thalamo-cortical hypermetabolism in patients with spasmodic torticollis

Introduction - The basal ganglia are thought to be involved in the primary dystonias, largely because of the repeated demonstration of neuropathological changes in these nuclei in the secondary dystonias. A hyperactivity of a network involving basal ganglia has been suggested in experimental animal dystonia. To test this hypothesis in humans, we studied the functional correlates of primary cervical dystonia using [F-18]FDG and PET. Material and methods - Regional cerebral glucose metabolism (rCMRglc) was measured in 10 patients with idiopathic torticollis (6 drug-free and 4 drug-naive) and in 15 normal controls, using 2-[F-18]-fluoro-2-deoxy-D-glucose ([F-18]FDG) and positron emission tomography (PET). Results - A significant hypermetabolism in the basal ganglia, thalamus, premotor-motor cortex and cerebellum in the patients compared with normal controls was found. The patients were correctly assigned to their clinical category by a discriminant function analysis with a total accuracy of 96%. Conclusion - The results support the hypothesis that a dysfunction of a subcortical-cortical motor network may play a role in the pathogenesis of focal dystonia, in agreement with the experimental dystonia models.