Brain Stimulation (May 2021)
Randomized double-blind sham-controlled trial of thalamic versus GPi stimulation in patients with severe medically refractory Gilles de la Tourette syndrome
Abstract
Background: There are still no sufficient data regarding the use of deep brain stimulation (DBS) in Gilles de la Tourette syndrome (GTS) and no agreement on optimal target. Objective: To compare efficacy and safety of bilateral DBS of thalamus (centromedian-ventro-oral internus, CM-Voi) versus posteroventral lateral globus pallidus internus (pvl GPi)) versus sham stimulation, and baseline in severe medically refractory GTS. Methods: In this randomized double-blind sham stimulation-controlled trial (RCT), 10 patients (3 women, mean age = 29.4 ± 10.2 SD, range 18–47) underwent three blinded periods each lasting three months including (i) sham, (ii) pvl GPi (on-GPi), and (iii) thalamic stimulation (on-thal) followed by an open uncontrolled long-term follow-up (up to 9 years) with individually determined target and stimulation settings. Results: Nine patients completed the RCT. At group level, on-GPi – but not on-thal – resulted in a significant tic reduction compared to baseline, but had no effect on premonitory urges and psychiatric comorbidities. Direct comparisons of targets resulted in inconsistent or negative (compared to sham) findings. During follow-up, we found no improvement of tics, comorbidities, and quality of life at group level, however, single patients benefitted continuously from thalamic DBS. At last follow-up 89.9 months (mean) after surgery, 50% of patients had discontinued DBS. Hardware infections occurred in 3/10 patients. Conclusion: Our data suggest that the initial effect of pvl GPi DBS is superior to thalamic (CM-Voi) DBS. While half of the patients discontinued treatment, single patients benefitted from thalamic DBS even after years. It is likely that outcome is influenced by various factors beyond the mere change in tic severity.
