BACKGROUND

Tourette syndrome (TS) is thought to result from dysfunction of the associative-limbic territories of the basal ganglia, and patients with severe symptoms of TS respond poorly to medication. High-frequency stimulation has recently been applied to patients with TS in open studies using the centromedian-parafascicular complex (CM-Pf) of the thalamus, the internal globus pallidus (GPi), or the anterior limb of the internal capsule as the principal target.

OBJECTIVE

To report the effect of high-frequency stimulation of the CM-Pf and/or the GPi, 2 associative-limbic relays of the basal ganglia, in patients with TS.

DESIGN

Controlled, double-blind, randomized crossover study.

SETTING

Medical research.

PATIENTS

Three patients with severe and medically refractory TS.

INTERVENTION

Bilateral placement of stimulating electrodes in the CM-Pf (associative-limbic part of the thalamus) and the GPi (ventromedial part).

MAIN OUTCOME MEASURES

Effects of thalamic, pallidal, simultaneous thalamic and pallidal, and sham stimulation on neurologic, neuropsychological, and psychiatric symptoms.

RESULTS

A dramatic improvement on the Yale Global Tic Severity Scale was obtained with bilateral stimulation of the GPi (reduction in tic severity of 65%, 96%, and 74% in patients 1, 2, and 3, respectively). Bilateral stimulation of the CM-Pf produced a 64%, 30%, and 40% reduction in tic severity, respectively. The association of thalamic and pallidal stimulation showed no further reduction in tic severity (60%, 43%, and 76%), whereas motor symptoms recurred during the sham condition. No neuropsychological, psychiatric, or other long-term adverse effect was observed.

CONCLUSIONS

High-frequency stimulation of the associative-limbic relay within the basal ganglia circuitry may be an effective treatment of patients with TS, thus heightening the hypothesis of a dysfunction in these structures in the pathophysiologic mechanism of the disorder.