Deep brain stimulation for tardive syndromes: Systematic review and meta-analysis.

Among the broad entity of tardive syndromes, tardive dystonia and classical tardive dyskinesia sometimes require advanced treatments like deep brain stimulation of the globus pallidus internum (Gpi-DBS) or the subthalamic nucleus (STN-DBS). This systematic review has analyzed the currently available literature reporting cases with either tardive dystonia or dyskinesia treated with DBS. The key words for the literature search included all tardive syndromes and "deep brain stimulation." Thirty-four level VI studies and one level II study with 117 patients were included. Level I studies were not identified. Only four of the patients had tardive dyskinesia. All the others had tardive dystonia. The majority had Gpi-DBS (n = 109). Patients had a mean age of 47.4 (± SD 14.7) years. The duration of follow-up was 25.6 months ± 26.2. The Abnormal Involuntary Movement Scale was reported in 51 patients with an improvement of 62 ± 15% and the Burke-Fahn-Marsden scale was reported in 67 cases with an improvement of 76 ± 21%. Reported adverse events were surgery-related in 7 patients, stimulation-induced in 12, and psychiatric in 3 patients. These reports thus suggest favorable effects of DBS and it seems to be relatively safe. DBS can be considered for patients with severe, medication-resistant symptoms. Controlled and randomized studies with blinded outcomes are needed.