BACKGROUND: Thalamic deep brain stimulation (DBS) has largely replaced 
radiofrequency thalamotomy as the treatment of choice for disabling, 
medication-refractory essential tremor. Recently, the development of 
transcranial, high-intensity focused ultrasound has renewed interest in thalamic 
lesioning. The purpose of this study is to compare functional outcomes and 
quality of life in essential tremor patients treated with either bilateral Vim 
DBS or unilateral procedures (focused ultrasound or DBS). We hypothesized that 
all three would effectively treat the dominant hand and positively impact 
functional outcomes and quality of life as measured with the Clinical Rating 
Scale for Tremor and the Quality of Life in Essential Tremor Questionnaire.
METHODS: This is a retrospective study of medication-refractory essential tremor 
patients treated at the University of Virginia with bilateral Vim DBS (n = 57), 
unilateral Vim DBS (n = 13), or unilateral focused ultrasound Vim thalamotomy 
(n = 15). Tremor was rated for all patients before and after treatment, using 
the Clinical Rating Scale for Tremor and Quality of Life in Essential Tremor 
Questionnaire.
RESULTS: Patients undergoing bilateral DBS treatment had more baseline tremor 
and worse quality of life scores. Patients had significant improvements in 
tremor symptoms and quality of life with all three treatments. Both DBS 
procedures improved axial tremor. No difference was seen in the degree of 
improvement in upper extremity tremor score, disability, or overall quality of 
life between bilateral and either unilateral procedure.
CONCLUSIONS: Bilateral thalamic DBS improves overall tremor more than unilateral 
DBS or focused ultrasound treatment; however, unilateral treatments are equally 
effective in treating contralateral hand tremor. Despite the greater overall 
tremor reduction with bilateral DBS, there is no difference in disability or 
quality of life comparing bilateral versus unilateral treatments.