Deep Brain Stimulation for Tourette Syndrome

Tourette syndrome (TS) is a chronic neurodevelopmental disorder characterised by motor and vocal tics. Tics often present early in childhood at 6-8 years old, commonly following a waxing and waning course before reaching a peak in severity at around 12 years of age [1]. Although symptoms can subside by early adulthood, a significant number of patients continue to experience severe tics across the lifespan [2]. It has been shown that tics often affect health-related quality of life and require active treatment intervention [3,4]. First line recommended treatment includes both pharmacotherapy, usually in the form of neuroleptics or atypical antipsychotics [5], and behavioural interventions, such as habit reversal therapy and exposure with response prevention [6]. In a proportion of patients, these interventions fail to provide adequate control over tic symptoms. This may be due to lack of efficacy or intolerable adverse effects, or a combination of both [7,8]. Surgical interventions may therefore be considered, in order to improve the quality of life of patients with severe and refractory tics that impact on their daily functioning and well-being [2]. Traditional forms of ablative surgery were invasive procedures, usually involving the frontal cortex, limbic system, thalamus and cerebellum, and sometimes associated with permanent disabling adverse effects, such as dystonia and paralysis [8-10]. However over the last decades, deep brain stimulation (DBS) with stereotactically-guided electrode implantation at selected targets has been identified as a safe, effective and potentially reversible alternative intervention for movement disorders such as Parkinson disease, tremor and dystonia [2,7,11]. More recently, DBS has also been implemented in the treatment of other severe neuropsychiatric disorders, such as refractory depression and obsessive-compulsive disorder (OCD