Role of deep brain stimulation in the treatment of secondary dystonia-dyskinesia syndromes.

Dystonia-dyskinesia syndromes (DDS) are severe disabling movement disorders, characterized by twisting and repetitive movements or abnormal postures. Movement disorders are differentiated as primary or secondary. Primary movement disorders are of genetic or idiopathic origin, whereas secondary forms result from exogenous injuries. A PubMed literature search identified 32 clinical research studies reporting on a total of 153 patients with secondary dystonia treated with deep brain stimulation. For 116 patients, the mean Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) score improved by 49%. The greatest mean BFMDRS improvement was achieved for tardive dyskinesia. The majority of patients were implanted in the globus pallidus. Fewer patients received thalamic or subthalamic nucleus stimulation. Electrical neuromodulation of subcortical structures can be very useful for a small number of patients with movement disorders due to a structural damage of the brain.