title: 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.
authors.affiliation: Lift Labs Design, San Francisco, California, USA.
authors.forename: Anupam
authors.initials: A
authors.lastname: Pathak
authors.forename: John A
authors.initials: JA
authors.lastname: Redmond
authors.forename: Michael
authors.initials: M
authors.lastname: Allen
authors.forename: Kelvin L
authors.initials: KL
authors.lastname: Chou
mesh_terms: D061725:Accelerometry; D000368:Aged; D000369:Aged, 80 and over; D020329:Essential Tremor / Q000451:nursing* / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D010865:Pilot Projects; D011597:Psychomotor Performance / Q000502:physiology*; D012656:Self-Help Devices; D012720:Severity of Illness Index
keywords: essential tremor; noninvasive device; treatment