1: Bilateral Deep Brain Stimulation [clinicaltrials_resource:NCT00056563/group/O1]

Bilateral Deep Brain Stimulation Bilateral Deep Brain Stimulation : The DBS site (STN or GPi) will be assigned on a random basis at the time the patient enters the surgical phase of the trial.

1: Bilateral Deep Brain Stimulation [clinicaltrials_resource:NCT00056563/group/O1]

Bilateral Deep Brain Stimulation Bilateral Deep Brain Stimulation : The DBS site (STN or GPi) will be assigned on a random basis at the time the patient enters the surgical phase of the trial.