Abstract
BACKGROUND: We explored whether a noninvasive handheld device using Active Cancellation of Tremor (ACT) technology could stabilize tremor-induced motion of a spoon in individuals with essential tremor (ET). METHODS: Fifteen ET subjects (9 men, 6 women) performed 3 tasks with the ACT device turned on and off. Tremor severity was rated with the Fahn-Tolosa-Marin Tremor Rating Scale (TRS). Subjective improvement was rated by subjects with the Clinical Global Impression Scale (CGI-S). Tremor amplitude was measured using device-embedded accelerometers in 11 subjects. RESULTS: TRS scores improved with ACT on (versus off) in all 3 tasks: holding (1.00 ± 0.76 vs. 0.27 ± 0.70; P = 0.016), eating (1.47 ± 1.06 vs. 0.13 ± 0.64; P = 0.001), and transferring (1.33 ± 0.82 vs. 0.27 ± 0.59; P = 0.001). CGI-S improved with eating and transferring, but not the holding task. Accelerometer measurements demonstrated 71% to 76% reduction in tremor with the ACT device on. CONCLUSIONS: This noninvasive handheld ACT device can reduce tremor amplitude and severity for eating and transferring tasks in individuals with ET.