Deep Brain Stimulation (DBS) for the Suppression of Tremor

This study is designed as a prospective, multi-centered study for 365 days in duration from device implantation. A maximum of 12 sites will enroll 160 patients. Each patient will be screened and then undergo a baseline evaluation followed by unilateral or bilateral implantation of the DBS system. During the implantation procedure, each patient will undergo a trial of stimulation in the operating room. The device may be internalized after a successful intra-operative trial or at a later surgery (no later than 4 weeks after initial lead placement). If the device is not activated immediately postsurgery, the patient may return to the clinic to determine optimum stimulation programming. Device programming will be optimized in as many visits as necessary following implantation. The day that the device is fully implanted will be classified as "Day 0" for each patient. After "Day 0" the patient will return to clinic for evaluations at, Day 90 (±14 days), and Day 180 (±14 days) and Day 365 (approximately 12 months ± 30 days after Day 0). These evaluations consist of the CRST, the QUEST, the SF36, Patient and caregiver Global Ratings and the Patient Satisfaction Rating. At Baseline and Day 180, the CRST evaluation session will be video recorded for analysis by an independent evaluator unaware of the functioning of the device. Additionally, at the Day 180 visit, the physician will have the option to provide the patient with amplitude control. A comparison of measures within the same person from pre-treatment to post-treatment will be performed. Also, pre-treatment and post-treatment group means and standard deviations will be determined. Patients completed follow-up visits as part of the original protocol (C-04-02) for one year (or in some cases longer if patient was bilaterally implanted) and continued to complete additional visits as part of the Long-Term Follow-up protocol (C-06-03) for up to 5 years post implant.