title: Development of method for quantifying essential tremor using a small optical device.
abstract: Clinical assessment scales are the most common means used by physicians to assess tremor severity. Some scientific tools that may be able to replace these scales to objectively assess the severity, such as accelerometers, digital tablets, electromyography (EMG) measurement devices, and motion capture cameras, are currently available. However, most of the operational modes of these tools are relatively complex or are only able to capture part of the clinical information; furthermore, using these tools is sometimes time consuming. Currently, there is no tool available for automatically quantifying tremor severity in clinical environments.
  
  
  
  We aimed to develop a rapid, objective, and quantitative system for measuring the severity of finger tremor using a small portable optical device (Leap Motion).
  
  
  
  A single test took 15s to conduct, and three algorithms were proposed to quantify the severity of finger tremor. The system was tested with four patients diagnosed with essential tremor.
  
  
  
  The proposed algorithms were able to quantify different characteristics of tremor in clinical environments, and could be used as references for future clinical assessments.
  
  
  
  A portable, easy-to-use, small-sized, and noncontact device (Leap Motion) was used to clinically detect and record finger movement, and three algorithms were proposed to describe tremor amplitudes.
authors.affiliation: Neurology Division, National Taiwan University Hospital, Hsinchu Branch, Taiwan.
authors.forename: Kai-Hsiang
authors.initials: KH
authors.lastname: Chen
authors.affiliation: Department of Mechanical Engineering, National Chiao Tung University, Taiwan.
authors.forename: Po-Chieh
authors.initials: PC
authors.lastname: Lin
authors.affiliation: Department of Mechanical Engineering, National Chiao Tung University, Taiwan.
authors.forename: Yu-Jung
authors.initials: YJ
authors.lastname: Chen
authors.affiliation: Department of Mechanical Engineering, National Chiao Tung University, Taiwan; Institute of Biomedical Engineering, National Chiao Tung University, Taiwan. Electronic address: bsyang@mail.nctu.edu.tw.
authors.forename: Bing-Shiang
authors.initials: BS
authors.lastname: Yang
authors.affiliation: Department of Neurology, National Taiwan University Hospital, Taiwan.
authors.forename: Chin-Hsien
authors.initials: CH
authors.lastname: Lin
mesh_terms: D061725:Accelerometry / Q000295:instrumentation* / Q000379:methods*; D000368:Aged; D000465:Algorithms; D020329:Essential Tremor / Q000175:diagnosis* / Q000503:physiopathology; D005240:Feasibility Studies; D005260:Female; D005385:Fingers / Q000503:physiopathology; D006801:Humans; D008297:Male; D055096:Optical Devices; D012720:Severity of Illness Index; D012815:Signal Processing, Computer-Assisted; D014202:Tremor / Q000175:diagnosis / Q000503:physiopathology
keywords: Clinical assessment; Essential tremor; Motion capture; Severity; Tremor evaluation algorithm