Mood and motor effects of thalamic deep brain stimulation surgery for essential tremor

Purpose: The aim of this study was to evaluate the effects of unilateral and bilateral ventralis intermedius (Vim) deep brain stimulation (DBS) on mood and motor function. Methods: Thirty-one consecutive medication refractory patients with essential tremor who underwent unilateral or bilateral Vim DBS at University of Florida and returned for at least 6 -month follow-up completed the Visual Analog Mood (VAMS), the Beck Depression Inventory (BDI), and the Tremor Rating Scale (TRS) before and after surgery. We excluded all patients who were implanted at other institutions. Results: The tense subscale of the VAMS improved significantly in both the unilateral and bilateral DBS groups (P < 0.001). On the VAMS afraid subscale, only the bilateral group trended toward improvement (P = 0.075). There were no significant changes for either group for the happy, confused, sad, angry, energetic or tired VAMS scores. TRS subscale scores all improved after unilateral and bilateral Vim DBS surgery (P < 0.001). Conclusions: Feelings of tenseness, tremor severity and ADLs improved following unilateral or bilateral Vim DBS for ET.