title: Unsupervised home monitoring of Parkinson's disease motor symptoms using body-worn accelerometers.
abstract: Current PD assessment methods have inherent limitations. There is need for an objective method to assist clinical decisions and to facilitate evaluation of treatments. Accelerometers, and analysis using artificial neural networks (ANN), have shown potential as a method of motor symptom evaluation. This work describes the development of a novel PD disease state detection system informed by algorithms based on data collected in an unsupervised, home environment. We evaluated whether this approach can reproduce patient-completed symptom diaries and clinical assessment of disease state.
  
  
  
  34 participants with PD wore bilateral wrist-worn accelerometers for 4 h in a research facility (phase 1) and for 7 days at home whilst completing symptom diaries (phase 2). An ANN to predict disease state was developed based on home-derived accelerometer data. Using a leave-one-out approach, ANN performance was evaluated against patient-completed symptom diaries and against clinician rating of disease state.
  
  
  
  In the clinical setting, specificity for dyskinesia detection was extremely high (0.99); high specificity was also demonstrated for home-derived data (0.93), but with low sensitivity (0.38). In both settings, sensitivity for on/off detection was sub-optimal. ANN-derived values of the proportions of time in each disease state showed strong, significant correlations with patient-completed symptom diaries.
  
  
  
  Accurate, real-time evaluation of symptoms in an unsupervised, home environment, with this sensor system, is not yet achievable. In terms of the amounts of time spent in each disease state, ANN-derived results were comparable to those of symptom diaries, suggesting this method may provide a valuable outcome measure for medication trials.
authors.affiliation: Department of Medicine, Northumbria Healthcare NHS Foundation Trust, United Kingdom. Electronic address: drjamesfisher@hotmail.com.
authors.forename: James M
authors.initials: JM
authors.lastname: Fisher
authors.affiliation: School of Computing Science, Newcastle University, United Kingdom.
authors.forename: Nils Y
authors.initials: NY
authors.lastname: Hammerla
authors.affiliation: School of Computing Science, Newcastle University, United Kingdom.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ploetz
authors.affiliation: School of Computing and Mathematics, Keele University, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Andras
authors.affiliation: Institute for Ageing and Health, Newcastle University, United Kingdom.
authors.forename: Lynn
authors.initials: L
authors.lastname: Rochester
authors.affiliation: Department of Medicine, Northumbria Healthcare NHS Foundation Trust, United Kingdom.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Walker
mesh_terms: D061725:Accelerometry / Q000379:methods*; D000368:Aged; D005260:Female; D006699:Home Care Services; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D010300:Parkinson Disease / Q000503:physiopathology*; D013997:Time Factors; D014584:User-Computer Interface
keywords: Parkinson's disease; body-worn sensors; home-monitoring