Deep Brain Stimulation of the Globus Pallidus Internus in Patients with Intractable Tourette Syndrome: A 1-year Follow-up Study

Abstract

Background: Deep brain stimulation (DBS) has been a promising treatment for patients with refractory Tourette syndrome (TS) for more than a decade. Despite successful DBS treatment of TS in more than 100 patients worldwide, studies with a large patient sample and long-term follow-up assessments are still scarce. Accordingly, we investigated the clinical efficacy and safety of globus pallidus internus (GPi) DBS in the treatment of intractable TS in 24 patients with a 1-year follow-up assessment.

Methods: Bilateral/unilateral GPi-DBS was performed in 24 patients with TS. We evaluated symptoms of tics and obsessive-compulsive disorder (OCD) through the Yale Global Tic Severity Scale (YGTSS) and Yale-Brown Obsessive-compulsive Scale (Y-BOCS). We used the Wechsler Adult Intelligence Scale-Revised in China (WAIS-RC) to evaluate the safety of the treatment. We conducted follow-up assessments of all patients for at least 12 months (12-99 months).

Results: Symptoms of tics and OCD were significantly relieved at a 12-month follow-up assessment. The mean YGTSS score was 74.04 ± 11.52, 49.83 ± 10.91, 32.58 ± 7.97, and 31.21 ± 8.87 at baseline, 3, 6, and 12 months, respectively. The mean YGTSS scores obtained at the follow-up assessments were significantly different from the baseline (P < 0.05). The improvement in motor tics was superior to that in phonic tics. The mean Y-BOCS scores were 21.61 ± 4.97, 18 ± 4.58, 14.39 ± 3.99, and 13.78 ± 4.56 at baseline, 3, 6, and 12 months, respectively (P < 0.05). We observed a remarkable improvement in psychiatric comorbidities, such as OCD and attention-deficit hyperactivity disorder, after the procedure. WAIS-RC scores were comparable before and after the operation. There were no severe postoperative complications.

Conclusion: GPi-DBS appears to comprehensively alleviate tic symptoms and psychiatric comorbidities in patients with TS, thus significantly improving patients' quality of life.

Figure 1

Y-BOCS scores before and after Gpi-DBS in TS patients. Compared with baseline values, Y-BOCS scores were statistically lower at 3, 6, and 12-month follow-up assessments. *P < 0.01 versus baseline. Y-BOCS: Yale-Brown Obsessive-compulsive Scale; GPi: Globus pallidus internus; DBS: Deep brain stimulation; TS: Tourette syndrome.

Figure 2

WAIS-RC scores before and after Gpi-DBS in TS patients. We found no significant difference between VIQ, PIQ, and FIQ scores at baseline, 3, 6, and 12-month assessments. WAIS-RC: Wechsler Adult Intelligence Scale-Revised in China; GPi: Globus pallidus internus; DBS: Deep brain stimulation; TS: Tourette syndrome; VIQ: Verbal intelligence quotient; PIQ: Performance-IQ; FIQ: Full-IQ.