Researchers from the Washington University School of Medicine in St. Louis, MO, performed a multicenter study to evaluate differences in regions of the brain between children with TS and controls. A total of 103 children and adolescents between the ages of 7 and 17 with TS were matched to 103 children and adolescents who did not have a history of tics.
The researchers applied voxel-based morphometry methods to test gray matter (GM) and white matter (WM) volume differences between the diagnostic groups, accounting for MRI scanner and sequence, age, sex, and total GM plus WM volume.
The results showed that the subjects in the TS group demonstrated lower WM volume bilaterally in orbital and medial prefrontal cortex, and greater GM volume in posterior thalamus, hypothalamus, and midbrain. These results demonstrate evidence for abnormal brain structure in children and youth with TS, consistent with and extending previous findings, and they point to new target regions and avenues of .
“In this study, we found changes primarily in brain regions connected to sensation and sensory processing,” co-author Kevin J. Black, MD, professor of psychiatry at the Washington University School of Medicine, said in a release. “Just as you or I might cough or sneeze due to a cold, a person with Tourette’s frequently will have a feeling that something is wrong, and the tic makes it feel better. A young man who frequently clears his throat may report that doing so is a reaction to a tickle or some other unusual sensation in his throat. Or a young woman will move her shoulder when it feels strange, and the movement, which is a tic, will make the shoulder feel better.”
The researchers do not know whether the extra gray matter is transmitting information that somehow contributes to tics or whether reduced amounts of white matter elsewhere in the brains of kids with Tourette’s may somehow influence the movements and vocalizations that characterize the disorder, according to Black. “This doesn’t tell us what happened to make the brain look this way,” he said in the release. “Are there missing cells in certain places, or are the cells just smaller? And are these regions changing as the brain tries to resist tics? Or are the differences we observed contributing to problems with tics? We simply don’t know the answers yet.”
The researchers aim to replicate their findings in a future study and determine if and how the brain regions they identified may contribute to Tourette’s syndrome, with a goal of developing more effective therapies.