Objective:

To determine if there is an increased risk of developing dementia in those with essential tremor (ET) compared to controls.

Background:

Essential tremor is a progressive neurological condition with motor dysfunction that contributes to reduced quality of life. Prior population studies noted increased risk for developing dementia in those with ET. In contrast, a prior study by our group demonstrated no increased risk for dementia in those with ET. The aim of this study is to longitudinally assess a larger cohort of ET and control subjects to compare the risk of developing dementia.

Design/Methods:

Subjects without dementia or other neurodegenerative disorders were selected from the Arizona Study of Aging and Neurodegenerative Disorders database. The ET group was divided into prevalent ET (ET diagnosis at study entry) and incident ET (ET developed during follow-up). There were 112 subjects with prevalent ET, 111 with incident ET, and 601 controls who were followed over a 10-year period. Subjects underwent annual movement disorders and neuropsychological evaluations. Baseline characteristics of the groups were compared using ANOVA F-test or chi-square test. The cumulative incidence of dementia was compared using Kaplan-Meier curves and a multivariate Cox-regression model.

Results:

Baseline group characteristics demonstrated older age in incident (81.5±6.7) and prevalent ET (79.6±6) compared to control (76.3±8.3) (p<0.001). Multivariate cox-regression assessing risk for developing dementia showed no significant difference between incident or prevalent ET vs control, or ET symptom onset duration. There was an increased risk for developing dementia with advancing age (hazard ratio 1.11, p < .001), presence of mild cognitive impairment at time of study entry (HR 6.98, p < .001) and male gender (HR 1.83, p = 0.004).

Conclusions:

There was no increased risk of dementia in those with both prevalent or incident ET within our 10 year study period.