A noninvasive handheld assistive device to accommodate essential tremor: A pilot study

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. © 2013 International Parkinson and Movement Disorder Society