EP 14. Clinical experiences with long term thalamic deep brain stimulation in severe Tourette Syndrome

Abstract

Introduction Thalamic deep brain stimulation is effective in reducing tics in patients with severe Tourette syndrome at the short-term. Here, we report on the long-term outcome. Methods Seven patients with refractory Tourette syndrome were referred to the Maastricht University Medical Centre and underwent bilateral thalamic deep brain stimulation between 2001 and 2008. The target was the centromedian nucleus-substantia periventricularis-nucleus ventro-oralis internus cross point of the thalamus. During the visits to the outpatient clinic, effects on tics, side-effects and stimulations parameters were evaluated. The follow-up duration varied between 12 to 78 months. Results Patient 1 showed an improvement on tics of 81.6% after 60 months, but due to higher voltage stimulation after some years needed to suppress the tics, side-effects became more severe and the target was changed to the anterior part of the internal pallidum. Patient 2 showed a tic improvement of 50% after 36 months, but due to increasing side-effects, he switched the stimulator permanently off. In patient 3 the stimulator is still active and showed satisfying results with an improvement on tics of 88.9% after 78 months. Patient 4 experienced a tic improvement of 34% after 16 months. However, side-effects became more severe, and when the whole system had to be removed due to a persisting hardware infection after six years, the target was changed to the anterior part of the internal pallidum. Patient 5 showed a minor tic improvement of 27.5% after 12 months. He was unsatisfied and went to abroad for stimulation of the external globus pallidus. Patient 6 developed cerebral atrophy due to a neurodegenerative disease and experienced several non-stimulation related side-effects. His tic improvement was 34% on the YGTSS after 26 months and he decided to turn the stimulator off. The positive effect on tics in patient 7 decreased over time until an improvement of only 9% at 60 months of follow-up. The target was changed to the anterior part of the internal pallidum. Conclusion Thalamic deep brain stimulation in patients with severe Tourette syndrome is effective in reducing tics, at least at the short-term. At the long-term only in one patient the stimulator is still active, in three patients the target was changed to the anterior part of the internal pallidum due to side-effects and three were unsatisfied and turned off their stimulator. There seems to be an increasing disbalance of effects versus side effects leading to either switching off the stimulator or re-surgery changing the target. These clinical cases reflect the strong heterogeneity of the disease, with serious comorbity, interfering with effects and side-effects of deep brain stimulation.