LAUSR

To identify CBF differences between individuals with Tic Disorder and healthy controls. The data for this study was acquired from a de-identified archival Single-Photon Emission Computed Tomography (SPECT) database. The sample included a healthy control group (n = 83,age M = 42.02,54.22% female) and a second group included individuals diagnosed with Tic Disorder (n = 177,age M = 33.54,83.05% male). Significant differences were found for gender [χ(2) = 41.16,p < .001] between groups. As a result, ANCOVAs were conducted to measure CBF differences across the brain using SPECT scans between the two groups while controlling for gender. Results showed significant differences between the two groups and perfusion in 4 brain regions. Hypo-perfusion in the Tic Disorder group was observed in the right basal ganglia [F(1,260) = 30.959,p < .001] and left [F(1,260) = 32.16,p < .001]. Hyper-perfusion was found in the right cerebellum [F(1,260) = 16.63,p < .001], and left [F(1,260) = 22.17,p < .001] in the same group. Results indicate that individuals with tic disorders have diminished CBF than healthy controls in both sides of the basal ganglia. This contrasts previous studies, which have shown that individuals with tic disorders have more CBF in the basal ganglia. Further research is needed to understand this inconsistency; a possible explanation is that there is an inhibiting effect on the basal ganglia. Increased CBF in both sides of the cerebellum supports previous research as this cortical area has been shown to have connections with the basal ganglia, activating the pathway that trigger the motor tics. Tic disorders are usually associated with other comorbidities therefore the sample may have other diagnoses that affect blood flow. Future research should control for potential comorbidities.