Dystonia describes a group of movement disorders characterized by involuntary muscle contractions which cause twisting involuntary movements and/or abnormal postures. Primary generalized dystonia often begins in childhood and over a number of years leads to a serious and debilitating illness. The effects of medication and physiotherapy are often disappointing. In the Netherlands a randomized, placebo-controlled and double-blind study has been started to examine the effects and risks of long-term deep brain stimulation in patients with primary generalized dystonia.