Comparison of the Efficacy of Double Monopolar Versus Interleaving Stimulation Modes for Pallidal Deep Brain Stimulation

Inclusion Criteria: * ages of 7 and 75 years * marked disability owing to primary generalized or segmental dystonia, despite optimal pharmacologic treatment * disease duration of at least 5 years. Exclusion Criteria: * previous brain surgery; * cognitive impairment (\< 120 points on the Mattis Dementia Rating Scale) * moderate-to-severe depression (\> 25 points on the Beck Depression Inventory) * marked brain atrophy as detected by magnetic resonance imaging * other medical or psychiatric coexisting disorders that could increase the surgical risk or interfere with completion of the trial