Functional mobility and postural control in essential tremor

Objective: To evaluate functional mobility and postural control in participants with essential tremor (ET). Design: Cross-sectional cohort study. Setting: Motor performance research laboratory. Participants: Sixteen participants with ET including head tremor (age, 59.4 +/- 12.0y), 14 participants with ET and no head tremor (age, 57.1 +/- 15.9y), and 28 healthy controls (age, 58.4 +/- 12.4y). Interventions: Not applicable. Main Outcome Measures: We assessed the Timed Up & Go, time to ascend and descend stairs, Dynamic Gait Index, and Berg Balance Scale (BBS). Participants completed the Activities-specific Balance Confidence Scale and the Human Activity Profile. We assessed postural control using center-of-pressure measures from force platform recordings of quiet standing in 5 conditions. Results: Participants with ET including head tremor performed worse than controls on all functional mobility performance and self-report measures (P<.05) except the BBS and stair descent time. Mean performance of ET participants without head tremor was intermediate between the other 2 groups. Sway speed measures of postural control showed similar patterns, but no significant group differences in post hoc analysis. There were no statistically significant or clinically important correlations between measures of tremor status and functional mobility status. Conclusions: Participants with ET show reduced functional mobility, especially those with head tremor.