BACKGROUND: Neurostimulation of the internal globus pallidus has been shown to 
be effective in reducing symptoms of primary dystonia. We compared this surgical 
treatment with sham stimulation in a randomized, controlled clinical trial.
METHODS: Forty patients with primary segmental or generalized dystonia received 
an implanted device for deep-brain stimulation and were randomly assigned to 
receive either neurostimulation or sham stimulation for 3 months. The primary 
end point was the change from baseline to 3 months in the severity of symptoms, 
according to the movement subscore on the Burke-Fahn-Marsden Dystonia Rating 
Scale (range, 0 to 120, with higher scores indicating greater impairment). Two 
investigators who were unaware of treatment status assessed the severity of 
dystonia by reviewing videotaped sessions. Subsequently, all patients received 
open-label neurostimulation; blinded assessment was repeated after 6 months of 
active treatment.
RESULTS: Three months after randomization, the change from baseline in the mean 
(+/-SD) movement score was significantly greater in the neurostimulation group 
(-15.8+/-14.1 points) than in the sham-stimulation group (-1.4+/-3.8 points, 
P<0.001). During the open-label extension period, this improvement was sustained 
among patients originally assigned to the neurostimulation group, and patients 
in the sham-stimulation group had a similar benefit when they switched to active 
treatment. The combined analysis of the entire cohort after 6 months of 
neurostimulation revealed substantial improvement in all movement symptoms 
(except speech and swallowing), the level of disability, and quality of life, as 
compared with baseline scores. A total of 22 adverse events occurred in 19 
patients, including 4 infections at the stimulator site and 1 lead dislodgment. 
The most frequent adverse event was dysarthria.
CONCLUSIONS: Bilateral pallidal neurostimulation for 3 months was more effective 
than sham stimulation in patients with primary generalized or segmental 
dystonia. (ClinicalTrials.gov number, NCT00142259 [ClinicalTrials.gov].).