Dystonia is a complex clinical movement disorder, and many patients remain poorly treated with medication and surgery. Deep brain electrical stimulation, as a functional surgical procedure, is increasingly used in the treatment of drug-refractory movement disorders. Introduction Dystonia is a neurological disorder in which abnormal movements or postures are caused by continuous or intermittent muscle contractions. Current therapeutic agents include anticholinergic drugs, dopamine, benzodiazepines, tetrabenazine, and baclofen. Botulinum toxin injections for the target muscles may also provide relief. Surgical interventions include nerve rhizotomy for severe cervical dystonia and thalamic and basal ganglia ablation for more generalized dystonia. Deep brain electrical stimulation (DBS) has emerged as one of the surgical interventions for drug-refractory torsional dystonia (torsional spasm), with advantages including reversible stimulation effects, modifiable as needed, and a relatively good safety profile. Selection of patients The selection of patients for DBS treatment is complex given the heterogeneity of the disease and the fact that different types of dystonia respond differently to stimulation. DBS is currently approved only for primary generalized, segmental, or cervical dystonia, and all other types of dystonia treated with DBS are used outside of the indication. Patients considered for treatment with DBS should be evaluated in the following areas: 1. Exclusion of patients who respond better to noninvasive therapy; 2. Clarification of factors associated with predicting positive and negative responses to stimulation therapy. A levodopa test is required to rule out levodopa-responsive dystonia. Patients who do not respond well to botulinum toxin treatment need to have their treatment target and dose reconfirmed as appropriate. Patients with psychogenic dystonia usually have a poor response to pharmacotherapy and should be referred for DBS. It is important to assess the patient for skeletal deformities, spasticity, and the presence of spinal cord pathology, all of which may reduce their response to DBS. Preoperative testing also includes MRI to rule out structural abnormalities that may contribute to secondary dystonia. Finally, screening for psychiatric symptoms or cognitive dysfunction is also required. The appropriate time to perform surgical treatment for DBS remains a controversial issue. In general, DBS surgery can be considered once it has been determined that the patient has failed to respond to medical therapy and needs to be performed before the appearance of complex skeletal deformities or cervical spinal cord lesions.