Introduction: Deep brain stimulation (DBS) has emerged as a safe and effective therapy for severe, treatment-refractory Tourette syndrome (TS), a potentially debilitating disorder affecting approximately 1:2000 adults in the US. Recent studies have demonstrated that DBS is effective in reducing TS symptoms as measured by the Yale Global Tic Severity Scale (YGTSS), but no studies, to our knowledge, have compared the effectiveness of DBS with conservative therapy.
Methods: We performed a meta-analysis of studies investigating patient outcomes reported as YGTSS scores after DBS surgery, pharmacotherapy, and behavioral therapy. Single case reports and studies with participant mean age <16 years or without YGTSS data were excluded. Data were pooled using a random effects model of inverse-variance weighted meta-analysis (n=174 for DBS, 133 for medications, 201 for behavioral therapy). All DBS targets, all medications, and all psychotherapeutic modalities were pooled.
Results: DBS resulted in a significantly larger reduction in YGTSS total score (49.9% ± 17.5%) than pharmacotherapy (22.5% ± 15.2%, P=0.001) or behavioral therapy (20.0% ± 11.3%, P<0.001). The complication/adverse effect rate was 0.15/case for DBS (including 0.04 major complications such as infection and lead migration per case) versus 1.13/case for medications and 0.60/case for psychotherapy. Groups were demographically similar, though baseline YGTSS total score for DBS patients was 80.0 ± 9.8 (mean ± SD; total 100), significantly greater than the baseline score for patients in medication (54.1 ± 9.8) or behavioral (48.2 ± 2.3) trials (P<0.001). Notably, there was no difference in effectiveness of DBS between targets (P=0.792).
Conclusions: Our data suggest that, despite greater baseline symptom severity, TS patients undergoing DBS experience greater symptomatic improvement with surprisingly low morbidity as compared with pharmacotherapy and behavioral therapy. Randomized controlled trials are warranted to pursue regulatory approval of DBS as a mainstream therapeutic option for patients with severe TS.
Patient Care: Our meta-analysis is the first study, to our knowledge, to demonstrate that deep brain stimulation leads to greater symptomatic improvement in Tourette syndrome versus medication or behavioral therapy. Our work paves the way for a randomized controlled trial that may ultimately lead to approval of DBS as a therapy for severe Tourette syndrome refractory to conservative therapy.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Identify the most common targets for deep brain stimulation in Tourette syndrome; 2) Understand the advantages and disadvantages of conservative versus surgical treatment of Tourette syndrome; 3) Identify avenues of future research into the effectiveness of neuromodulatory treatment of Tourette syndrome