The severity of Tourette syndrome (TS) typically peaks just before adolescence and diminishes afterward. In some patients, however, TS progresses into adulthood, and proves to be medically refractory. The authors conducted a prospective double-blind crossover trial of bilateral thalamic deep brain stimulation (DBS) in five adults with TS.
Bilateral thalamic electrodes were implanted. An independent programmer established optimal stimulator settings in a single session. Subjective and objective results were assessed in a double-blind randomized manner for 4 weeks, with each week spent in one of four states of unilateral or bilateral stimulation. Results were similarly assessed 3 months after unblinded bilateral stimulator activation while repeated open programming sessions were permitted.
In the randomized phase of the trial, a statistically significant (p < 0.03, Friedman exact test) reduction in the modified Rush Video-Based Rating Scale score (primary outcome measure) was identified in the bilateral on state. Improvement was noted in motor and sonic tic counts as well as on the Yale Global Tic Severity Scale and TS Symptom List scores (secondary outcome measures). Benefit was persistent after 3 months of open stimulator programming. Quality of life indices were also improved. Three of five patients had marked improvement according to all primary and secondary outcome measures.
Bilateral thalamic DBS appears to reduce tic frequency and severity in some patients with TS who have exhausted other available means of treatment.