Successful chronic bilateral globus pallidus internus stimulation for intractable Gilles de la Tourette syndrome: a case report

Objective: The usefulness of deep brain stimulation (DBS) with the globus pallidus internus (GPI) being one possible target in Gilles de la Tourette syndrome (GTS) has recently come into focus. We here present the immediate post-operative results and data from a 8-month follow-up of a patient with intractable GTS in whom bilateral GPI-DBS was performed.

Methods: The 44-year old female patient had been suffering from multiple severely disabling vocal and motor tics as well as compulsive tendencies since the age of 5 years. The diagnosis of GTS was established at the age of 28 years. Any applied medical treatment (including typical and atypical neuroleptics, benzodiazepines and neuromodulatory approaches) was without lasting significant relief for the patient. After informed consent, electrode-implantation (DBS 3389, Medtronic) for bilateral GPI-stimulation was performed under propofol anaesthesia with MRI-guided stereotaxy using a modified Leksel/Lerch system. After 5 days of successful stimulation by an external test stimulation system, permanent implantation of the stimulation system (Soletra, Medtronic) was performed. Initially, standard settings also used in GPI-DBS for dystonia were chosen (monopolar stimulation, amplitude 2.5 V, pulse width 120µs, frequency 130 pps). Electrode position was verified by MRI and clinical outcome was assessed using the Yale Global Tic Severity Scale (YGTSS), the Verbal learning memory test (VLMT) and the Stroop-Test.

Results: There was a significant improvement of symptoms already during the first week. After 6 weeks, the YGTSS score had improved from 83 to 28 (66.3%). At 8-months follow-up there was a further significant relief of clinical symptoms along with an improvement of the YGTSS score to 18 (78.3%). Neuropsychological testing pre- and post-operatively showed an identical cognitive function. No surgery or therapy-related morbidity was observed. Stimulation parameters had to be adjusted for optimal effectiveness during follow-up with the last amplitude being relatively high at 4.2 V.

Conclusion: GPI deep brain stimulation might become a valuable effective and safe therapy in otherwise intractable GTS. Further (prospective) studies will be necessary to determine its clinical (long-term) effectiveness.