title: Clinician versus machine: reliability and responsiveness of motor endpoints in Parkinson's disease.
abstract: BACKGROUND
  Enhancing the reliability and responsiveness of motor assessments required to demonstrate therapeutic efficacy is a priority for Parkinson's disease (PD) clinical trials. The objective of this study is to determine the reliability and responsiveness of a portable kinematic system for quantifying PD motor deficits as compared to clinical ratings.
  
  
  METHODS
  Eighteen PD patients with subthalamic nucleus deep-brain stimulation (DBS) performed three tasks for evaluating resting tremor, postural tremor, and finger-tapping speed, amplitude, and rhythm while wearing a wireless motion-sensor unit (Kinesia) on the more-affected index finger. These tasks were repeated three times with DBS turned off and at each of 10 different stimulation amplitudes chosen to yield small changes in treatment response. Each task performance was video-recorded for subsequent clinician rating in blinded, randomized order. Test-retest reliability was calculated as intraclass correlation (ICC) and sensitivity was calculated as minimal detectable change (MDC) for each DBS amplitude.
  
  
  RESULTS
  ICCs for Kinesia were significantly higher than those for clinician ratings of finger-tapping speed (p < 0.0001), amplitude (p < 0.0001), and rhythm (p < 0.05), but were not significantly different for evaluations of resting or postural tremor. Similarly, Kinesia scores yielded a lower MDC as compared with clinician scores across all finger-tapping subscores (p < 0.0001), but did not differ significantly for resting and postural tremor.
  
  
  CONCLUSIONS
  The Kinesia portable kinematic system can provide greater test-retest reliability and sensitivity to change than conventional clinical ratings for measuring bradykinesia, hypokinesia, and dysrhythmia in PD patients.
authors.affiliation: Great Lakes NeuroTechnologies Inc., 10055 Sweet Valley Drive, Cleveland, OH 44125, USA. Electronic address: dheldman@glneurotech.com.
authors.forename: Dustin A
authors.initials: DA
authors.lastname: Heldman
authors.affiliation: UC Neuroscience Institute, Department of Neurology, Gardner Center for Parkinson's Disease and Movement Disorders, University of Cincinnati, Cincinnati, OH, USA.
authors.forename: Alberto J
authors.initials: AJ
authors.lastname: Espay
authors.affiliation: Departments of Neurology, Henry Ford Hospital and Wayne State University School of Medicine, West Bloomfield, MI, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: LeWitt
authors.affiliation: Great Lakes NeuroTechnologies Inc., 10055 Sweet Valley Drive, Cleveland, OH 44125, USA.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Giuffrida
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D046690:Deep Brain Stimulation / Q000379:methods; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D018476:Hypokinesia / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology* / Q000628:therapy*; D011596:Psychomotor Disorders / Q000209:etiology; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D020531:Subthalamic Nucleus / Q000502:physiology*; D014202:Tremor / Q000209:etiology; D014741:Video Recording
keywords: Bradykinesia; Kinesia; Parkinson's disease; Tremor; UPDRS