Objective: To investigate whether outcome of thalamic deep brain stimulation (DBS) for Tourette Syndrome can be predicted by functional connectivity estimates seeding from individual stimulation sites.

Background: Thalamic DBS is an evolving therapy for severe, treatment-refractory Tourette syndrome. It is unknown which functionally connected networks need to be modulated to obtain optimal treatment results.

Method: 15 patients with treatment-refractory TS who underwent thalamic DBS were enrolled in this study. Treatment response was assessed six and twelve months after DBS surgery using the Yale Global Tic Severity Scale (YGTSS) tic score and the Yale-Brown Obsessive-compulsive Scale (Y-BOCS) as a secondary outcome measurement. For each time point, functional connectivity maps seeding from stimulation sites were calculated based on normative resting-state functional connectivity data. The resulting n = 30 maps (for six and twelve months’ follow-ups) were analyzed using a full-factorial model to identify clusters of functional connectivity associated with DBS outcome controlling for time of outcome assessment and intrasubject variability. To validate the obtained functional connectivity pattern associated with treatment outcome, we performed a leave-one-out cross-validation.

Results: We observed significant clusters of functional connectivity comprising the medial frontal cortex, bilateral insulae and the thalamus associated with tic reduction after surgery. A significant negative association was found within clusters located in the temporal lobe, cerebellum and orbitofrontal cortex. The overall optimal connectivity pattern was able to predict individual outcomes in a leave-one-out cross-validation. In contrast, improvements of obsessions and compulsions were linked to connectivity with the prefrontal cortex.

Conclusion: We delineated a specific functional connectivity profile seeding from stimulation sites that predicted outcome of thalamic DBS in patients with Tourette Syndrome comprising areas involved in the processing of premonitory urges and tic execution. Our results extend our current understanding of the neural mechanisms of effective neuromodulation for Tourette Syndrome. A preliminary analysis of parts of the present study has been presented at the 11th European Conference on Tourette Syndrome & Tic disorders 2018 (https://f1000research.com/posters/8-1641).

« Back to MDS Virtual Congress 2021

MDS Abstracts - https://www.mdsabstracts.org/abstract/functional-connectivity-predictive-of-efficacy-for-thalamic-deep-brain-stimulation-for-tourette-syndrome/