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Efficacy and safety of deep brain stimulation in patients with medication-induced tardive dyskinesia and/or dystonia: a systematic review.

BACKGROUND
Tardive dyskinesia and dystonia (TDD) are severe side effects of dopamine-blocking agents, particularly antipsychotics. While deep brain stimulation (DBS) has proven effective in the treatment of TDD, little is known about the possible psychiatric complications of DBS in psychiatric patients.


OBJECTIVE
To assess the efficacy and safety, specifically the psychiatric side effects, of DBS in patients with medication-induced TDD.


DATA SOURCES
PubMed and EMBASE databases were searched systematically on May 25, 2011, for articles written in English, using the search terms deep brain stimulation AND tardive.


STUDY SELECTION
Of the 88 original articles retrieved, 17 studies involving 50 patients with TDD who underwent DBS were included in the review.


DATA EXTRACTION
Data on the severity of the movement disorders before and after DBS, as rated on the Burke-Fahn-Marsden Dystonia Rating Scale or similar scales, were extracted. Data on psychiatric symptoms before and after DBS were used to calculate the percent improvement per patient per rating scale. Overall improvement and confidence intervals were calculated using a 1-sample, 2-sided Student t test.


RESULTS
The mean improvement of TDD of the combined patients 3 to 76 months after implantation was 77.5% (95% CI, 71.4%-83.3%; P < .000) on the Burke-Fahn-Marsden Dystonia Rating Scale. Of the 50 patients, 1 experienced an exacerbation of depression, and 1 experienced an exacerbation of psychosis.


CONCLUSIONS
DBS seems to be effective and relatively safe for patients with treatment-resistant TDD; however, the results should be interpreted with caution, as most of the data are from case reports and small trials.