Bilateral pallidal deep brain stimulation in myoclonus-dystonia: our experience in three cases and their follow-up

Myoclonus-dystonia syndrome (MDS) is an autosomal dominant movement disorder caused by mutations in the SGCE gene. MDS is characterized by mild dystonia and myoclonic jerks, and a constellation of psychiatric manifestations. Deep brain stimulation (DBS) of bilateral internal globus pallidus (GPi) has recently been introduced as a new and beneficial technique to improve motor symptoms in MDS. We report three proven genetically MDS cases with successful response to DBS, and their clinical evolution over years. DBS improves significantly the Unified Myoclonus Rating Scale and Burke-Fahn-Marsden Dystonia Rating Scale in all three patients. This improvement is sustained over the years and no major adverse events were recorded. DBS stimulation parameters employed are justified and compared with cases reported throughout the literature. DBS of bilateral GPi is an effective and safe therapy to be considered in MDS refractory cases. Careful neuropsychological evaluation is essential inside the presurgery planning. Correct location of the DBS electrodes and individualized selection of stimulation parameters in each case are the main determinants of the best clinical response.