Deep brain stimulation (DBS) may improve disabling tics in severely affected medication and behaviorally resistant Tourette syndrome (TS). Here we review all reported cases of TS DBS and provide updated recommendations for selection, assessment, and management of potential TS DBS cases based on the literature and implantation experience. Candidates should have a Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM V) diagnosis of TS with severe motor and vocal tics, which despite exhaustive medical and behavioral treatment trials result in significant impairment. Deep brain stimulation should be offered to patients only by experienced DBS centers after evaluation by a multidisciplinary team. Rigorous preoperative and postoperative outcome measures of tics and associated comorbidities should be used. Tics and comorbid neuropsychiatric conditions should be optimally treated per current expert standards, and tics should be the major cause of disability. Psychogenic tics, embellishment, and malingering should be recognized and addressed. We have removed the previously suggested 25-year-old age limit, with the specification that a multidisciplinary team approach for screening is employed. A local ethics committee or institutional review board should be consulted for consideration of cases involving persons younger than 18 years of age, as well as in cases with urgent indications. Tourette syndrome patients represent a unique and complex population, and studies reveal a higher risk for post-DBS complications. Successes and failures have been reported for multiple brain targets; however, the optimal surgical approach remains unknown. Tourette syndrome DBS, though still evolving, is a promising approach for a subset of medication refractory and severely affected patients.

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IMPORTANCECollective evidence has strongly suggested that deep brain stimulation (DBS) is a promising therapy for Tourette syndrome.OBJECTIVE To assess the efficacy and safety of DBS in a multinational cohort of patients with Tourette syndrome.

Most models of dystonia pathophysiology predict alterations of activity in the basal ganglia thalamocortical motor circuit. The globus pallidus interna (GPi) shows bursting and oscillatory neuronal discharge in both human dystonia and in animal models, but it is not clear which intrinsic basal ganglia pathways are implicated in this abnormal output. The subthalamic nucleus (STN) receives prominent excitatory input directly from cortical areas implicated in dystonia pathogenesis and inhibitory input from the external globus pallidus. The goal of this study was to elucidate the role of the STN in dystonia by analyzing STN neuronal discharge in patients with idiopathic dystonia. Data were collected in awake patients undergoing microelectrode recording for implantation of STN deep brain stimulation electrodes. We recorded 62 STN neurons in 9 patients with primary dystonia. As a comparison group, we recorded 143 STN neurons in 20 patients with Parkinson's disease (PD). Single-unit activity was discriminated off-line by principal component analysis and evaluated with respect to discharge rate, bursting, and oscillatory activity. The mean STN discharge rate in dystonia patients was 26.3 Hz (SD 13.6), which was lower than that in the PD patients (35.6 Hz, SD 15.2), but higher than published values for subjects without basal ganglia dysfunction. Oscillatory activity was found in both disorders, with a higher proportion of units oscillating in the beta range in PD. Bursting discharge was a prominent feature of both dystonia and PD, whereas sensory receptive fields were expanded in PD compared with dystonia. The STN firing characteristics, in conjunction with those previously published for GPi, suggest that bursting and oscillatory discharge in basal ganglia output may be transmitted via pathways involving the STN and provide a pathophysiologic rationale for STN as a surgical target in dystonia.