title: Objective assessment of postural stability in Parkinson's disease using mobile technology.
abstract: BACKGROUND
  A significant gap remains in the ability to effectively characterize postural instability in individuals with Parkinson's disease. Clinical evaluation of postural declines is largely subjective, whereas objective biomechanical approaches are expensive and time consuming, thus limiting clinical adoption. Recent advances in mobile devices present an opportunity to address the gap in the quantification of postural stability. The aim of this project was to determine whether kinematic data measured by hardware within a tablet device, a 3rd generation iPad, was of sufficient quantity and quality to characterize postural stability.
  
  
  METHODS
  Seventeen patients and 17 age-matched controls completed six balance conditions under altered surface, stance, and vision. Simultaneous kinematic measurements were gathered from a three-dimensional motion capture system and tablet.
  
  
  RESULTS
  The motion capture system and tablet provided similar measures of stability across groups. In particular, within the patient population, correlation between the two systems for peak-to-peak, normalized path length, root mean square, 95% volume, and total power values ranged from 0.66 to 1.00. Kinematic data from five balance conditions--double-leg stance with eyes open on a foam surface, double-leg stance with eyes closed on firm and foam surfaces, and tandem stance on firm and foam surfaces--were capable of discriminating patients from controls.
  
  
  CONCLUSIONS
  The hardware within the tablet provides data of sufficient accuracy for the quantification of postural stability in patients with Parkinson's disease. The objectivity, portability, and ease of use of this device make it ideal for use in clinical environments lacking sophisticated biomechanical systems.
authors: Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.|Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, Ohio, USA.
authors: Sarah J
authors: SJ
authors: Ozinga
authors: Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.|Center for Neurological Restoration, Cleveland Clinic, Cleveland, Ohio, USA.
authors: Andre G
authors: AG
authors: Machado
authors: Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.
authors: Mandy
authors: M
authors: Miller Koop
authors: Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.|Center for Neurological Restoration, Cleveland Clinic, Cleveland, Ohio, USA.
authors: Anson B
authors: AB
authors: Rosenfeldt
authors: Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.|Center for Neurological Restoration, Cleveland Clinic, Cleveland, Ohio, USA.
authors: Jay L
authors: JL
authors: Alberts
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena / Q000502:physiology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000295:instrumentation* / Q000379:methods*; D009038:Motion; D010300:Parkinson Disease / Q000150:complications*; D004856:Postural Balance / Q000502:physiology*; D012678:Sensation Disorders / Q000175:diagnosis* / Q000209:etiology*; D012720:Severity of Illness Index; D013223:Statistics as Topic
keywords: Parkinson's disease; biomechanics; consumer electronics device; postural instability