Chronic Versus Intermittent Deep Brain Stimulation for Essential Tremor

The proposed study is a randomized, single blind trial of intermittent versus continuous stimulation among essential tremor (ET) patients with a chronic history of continuous stimulation. The trial is 10 weeks in length with clinical evaluations (about 60 minutes) performed on weeks 1, 2, 6, and 10, and phone interviews (about 5 minutes) on weeks 3, 4, 5, 7, 8, and 9. The study includes outcome measures of tremor, stimulation-induced side effects, sleep quality, and voltage threshold for optimal tremor control and sustained side-effects.

Inclusion criteria

• individuals with essential tremor who are at least 6 months status-post thalamic stimulator placement
• maintained a consistent chronic or intermittent stimulation schedule for at least 4 consecutive weeks prior to study enrollment
• no changes in stimulation parameters for at least 2 consecutive months prior to study enrollment

Exclusion criteria

• patients with clinically significant dementia (i.e., a score less than 24 out of 30 on the Mini Mental Status Exam14)
• women who are not post-menopausal
• patients with other significant neurological or psychiatric disease other than essential tremor
• patients treated with pallidotomy or thalamotomy
• patients with significant psychiatric disturbance as determined by Diagnostic and Statistical Manual-IV criteria which would make informed consent/cooperation problematic