Prevalence and incidence of Deep Brain Stimulation and Focused Ultrasound in a cohort of elders with Essential Tremor.

Deep Brain Stimulation (DBS) and Focused Ultrasound Thalamotomy (FUS) are important surgical alternatives for managing essential tremor (ET). Studies of the prevalence (i.e., the proportion of cases reporting a surgical procedure at a given observation), the incidence (i.e., the proportion of cases reporting new occurrences of a surgical procedure at a given observation), and the surgical rate (i.e., the proportion of cases with no history of surgery who underwent a surgical procedure during a given time interval) of DBS and FUS in ET cases are few and have limitations. We obtained surgical histories from 346 ET participants in a longitudinal research study that ascertained cases outside of treatment centers. 283 cases participated in follow-up evaluations at 18, 36, 54, 72 and 90 months (mean length of observation = 4.4 ± 2.5 years). The cumulative prevalence of DBS and FUS were 0.046 % (Confidence Interval [CI] = 0.024 to 0.068) and 0.035 % (CI = 0.016 to 0.054), respectively. The cumulative incidence (9.44 per 1000 person-years, and 9.43 per 1000 person-years, respectively) and annual surgical rates (0.009, and 0.009, respectively) observed for DBS and FUS were similar. Reported rates for DBS were lower than reported from clinic-based studies. To date, no other studies have documented the proportion of individuals with ET who have undergone FUS, and only three studies report the proportion who underwent DBS. All of the latter ascertained cases from treatment centers, biasing estimates upwards. Our data add to the understanding of surgical rates for ET.