Conference Coverage
BERLIN—A common medication used for the symptomatic treatment of dystonia has been shown to target brain abnormalities in the cerebral cortex in patients with cervical dystonia, according to a study presented at the 20th International Congress of Parkinson’s Disease and Movement Disorders.
Roxana G. Burciu, PhD, a postdoctoral fellow, and a team of researchers at the University of Florida, Gainesville, aimed to assess with fMRI task-related brain activity in patients with cervical dystonia with and without a single-dose administration of trihexyphenidyl, an anticholinergic medication. For decades, anticholinergic medications have been commonly prescribed for patients with varying types of dystonia, but their mechanism of action has not been determined. Although it was previously thought that anticholinergic medications primarily affect the basal ganglia, the results of this study are evidence that they are effective in other areas of the brain, particularly in the cerebral cortex.
Roxana G. Burciu, PhD
Sixteen patients with idiopathic cervical dystonia were compared using a 3T MRI scanner with 16 age- and gender-matched healthy individuals. Patients with cervical dystonia were scanned twice, both off-medication and on average two hours after a single dose of trihexyphenidyl. Control subjects did not receive the medication and were only scanned once. While off medication, the patients had reduced motor activity compared with the healthy subjects. After administration of trihexyphenidyl, there was an increase in motor-related activity in middle frontal gyrus and primary somatosensory cortex. The results suggest that somatosensory processing in cervical dystonia can be acutely changed through trihexyphenidyl administration.
Hyder A. Jinnah, MD, PhD, Professor of Neurosurgery, Human Genetics, and Pediatrics at Emory University School of Medicine in Atlanta, said, “The study by Burciu and colleagues is the first attempt to determine what part of the brain is influenced by anticholinergic drugs in dystonia. Before treatment, the patients with cervical dystonia showed abnormal activity in multiple brain regions. After treatment, the abnormal brain activity was at least partly corrected in two regions. Both of these regions were in the cerebral cortex, not the basal ganglia. This study provides clues towards which regions of the brain might be abnormal, and how trihexyphenidyl might correct these abnormalities.”
Dr. Jinnah added, “Like any good study, the findings from this study lead to many more questions than answers. Do the brain abnormalities found reflect a cause for dystonia, or a consequence of it? Does the result mean that these medications work in the cortex, not the basal ganglia, as previously believed? Why do patients with cervical dystonia have brain abnormalities that show up when they use their hands, which are not affected? Does the drug affect the brains of normal people who do not have dystonia in the same way? How can we exploit this new information to improve the value of anticholinergics for patients with dystonia?”