Clinical characteristics of patients with parkinson’s disease and essential tremor undergoing deep brain stimulation surgery at columbia university medical center, 2009–2014

Background: Only a minority of patients with essential tremor (ET) and Parkinson’s disease (PD) undergo deep brain stimulation (DBS) surgery. Data on patient selection factors are useful. Objectives: To compare the clinical characteristics of ET and PD patients who underwent DBS surgery with those of patients who had not undergone surgery. Methods: We abstracted data from the electronic medical records of 121 PD and 34 ET patients who underwent DBS surgery at Columbia University Medical Center during the period 2009–2014. We compared this group with 100 randomly selected PD and 100 randomly selected ET patients at the Center who had not undergone DBS surgery. Results: Among other differences, age of onset in PD patients who had undergone surgery was younger than in those who did not: 14.9% vs. 3.0% with onset before age 40 (P = 0.003). They had also tried nearly double the number of medications (3.9 ± 1.7 vs. 2.3 ± 1.5, P < 0.001). Interestingly, there was no difference in the proportion of patients with tremor (81.0% vs. 88.0%, P = 0.16). Medical co-morbidities (heart and lungs) were less common in the PD patients who underwent DBS surgery. In the ET group, tremor causing impairment in activities of daily living occurred in all surgical patients compared to 73.0% of non-surgical patients (P < 0.001). The former had tried nearly double the number of medications compared to the latter (3.2 ± 1.7 vs. 1.3 ± 1.3, P < 0.001). Conclusions: These data add to our understanding of the numerous clinical factors associated with patient referral to DBS surgery.