Effects of chronic alcohol consumption on long-term outcomes of thalamic deep brain stimulation for essential tremor.

The prevalence of essential tremor (ET) is about 4% above 40years of age. Chronic alcohol consumption is present in around 20% of patients with ET. Our objective was to identify whether chronic alcohol consumption was associated with a negative effect on tremor outcome after thalamic deep brain stimulation (DBS) in ET patients. We conducted a retrospective chart review, from January 2005 to December 2012, from which 23 patients who had ventral intermediate nucleus (Vim)-DBS surgery for ET were identified. Seven patients had a positive history of chronic alcohol consumption. We defined as chronic alcohol users those patients with a habit of drinking alcohol every day in order to suppress tremor. In the overall group of 23 patients, there was a reduction in the median tremor score from 8 pre-operatively, to 1 post-operatively (p<0.0001). The alcohol consumers group experienced a reduction in the median tremor score from 6 pre-operatively to 0 post-operatively (p=0.03). The non-alcohol consumers group had a reduction in the median tremor score from 8 pre-operatively to 1.7 post-operatively (p<0.0001). Both groups of patients experienced significant benefit from thalamic DBS. A larger study may reveal statistically significant differences between subgroups.