Longitudinal Magnetic Resonance Imaging (MRI) Analysis of the Developmental Changes of Tourette Syndrome Reveal Reduced Diffusion in the Cortico-Striato-Thalamo-Cortical Pathways

There is evidence that cortico-striato-thalamo-cortical pathways are involved in Tourette syndrome. We performed a longitudinal imaging study in 22 patients and 21 healthy controls in order to examine the development of tics and its correlation with magnetic resonance imaging (MRI) findings. Patients were divided in a group with persisting and a group with remission of tics. We found a decrease in volume of left putamen in controls, but not in patients. We found changes in mean diffusivity between patients and controls in right caudate nucleus, thalamus, and frontal lobe. In contrast to controls, parallel and perpendicular diffusivity decreased in patients and were most pronounced in the patients with persisting tics compared to those with remission. The findings suggest that the development of the brain in patients with remission resembles the normal development more than in patients with persistent tics. This could reflect a change in brain structure or compensatory mechanisms in the brain.