Positron emission tomography in patients with benign essential blepharospasm.
PURPOSE: To identify possible abnormalities in regional cerebral glucose metabolism in patients with benign essential blepharospasm or Meige syndrome using positron emission tomography. METHODS: Ten patients with benign essential blepharospasm and one patient with Meige syndrome were examined using positron emission tomography with deoxyglucose labeled with fluorine 18. The severity of muscle spasm at the time of positron emission tomography was recorded in each patient. In five patients, positron tomography was performed on two occasions (once before and again 1 to 2 weeks after botulinum injection) to look for reproducibility of the findings on positron emission tomography also to see if there was any correlation between the severity of symptoms and positron emission tomography findings. RESULTS: The mean reference ratio for fluorodeoxyglucose F18 metabolism was significantly elevated in the striatum compared with the frontal, temporal, or parietal regions. Glucose metabolism was also elevated in the thalami. There was no correlation between the severity of blepharospasm and the degree of hyperactivity in the striatum. In the patients who underwent positron emission tomography scanning on two occasions, there was no significant difference between the two studies in any of the regions analyzed. CONCLUSIONS: The authors' findings support the hypothesis that benign essential blepharospasm and Meige syndrome may be associated with overactivity of the striatum and the thalamus. Positron emission tomography may prove to be a useful research tool and a possible adjunct diagnostic technique for benign essential blepharospasm and Meige syndrome.