Positron emission tomography scanning in essential blepharospasm

PURPOSE: To localize in the brain using positron emission tomography neuroimaging with ¹⁸fluorodeoxyglucose [PET (¹⁸FDG)] differences in glucose metabolism between patients with essential blepharospasm (EB) and controls. DESIGN: Prospective case-control study. METHODS: Positron emission tomography neuroimaging with ¹⁸fluorodeoxyglucose was performed in 11 patients with EB and 11 controls matched for age and gender. Global analysis of images was used to localize differences in glucose metabolism between groups. RESULTS: Multiple cortical and subcortical abnormalities were observed in EB patients in comparison with controls. Cortical areas with the largest and most significant clusters of increased glucose uptake were the inferior frontal gyri, right posterior cingulate gyrus, left middle occipital gyrus, fusiform gyrus of the right temporal lobe, and left anterior cingulate gyrus. Cortical areas with the largest and most significant clusters of decreased glucose uptake were the inferior frontal gyri, ventral to the area of increased glucose metabolism. Subcortical abnormalities, consisting of increased glucose uptake, involved the right caudate and consisting of decreased glucose uptake, involved the left inferior cerebellar hemisphere and thalamus. CONCLUSIONS: Global analysis of positron emission tomography neuroimaging with ¹⁸fluorodeoxyglucose neuroimaging in EB patients in comparison with controls demonstrates a pattern of abnormalities involving several cortical and subcortical areas that control blinking, including the inferior frontal lobe, caudate, thalamus, and cerebellum.