Unilateral and bilateral constant-current ventralis intermedius (VIM) deep brain stimulation (DBS) significantly improves upper extremity tremor, activities of daily living (ADL), quality of life, and depression in patients with severe essential tremor (ET), according to a recent study. A prospective, controlled, multicenter study was conducted at 12 academic centers. Researchers investigated the safety and efficacy of unilateral and bilateral constant-current DBS of the VIM nucleus of the thalamus in patients with ET whose tremor was inadequately controlled by medications. 127 patients were implanted with VIM DBS. They found:

• The blinded, primary outcome variable (n=76) revealed a mean improvement of 1.25 ± 1.26 points in the target limb tremor rating scale (TRS) score in the arm contralateral to DBS.
• Secondary outcome variables at 1 year revealed significant improvements in quality of life, depression symptoms, and ADL scores.
• 47 patients had a second contralateral VIM-DBS, and this group demonstrated reduction in second-sided tremor at 180 days.