title: Reliability of impairment and physical performance measures for persons with Parkinson's disease.
abstract: OBJECTIVE
  Parkinson's disease (PD) is characterized by rigidity, postural instability, bradykinesia, and tremor, as well as other musculoskeletal impairments and functional limitations. The purpose of this investigation was to determine the reliability and stability of measures of impairments and physical performance for people in the early and middle stages of PD, Subjects. Thirteen men and 2 women in Hoehn and Yahr stages 2 and 3 of PD participated. Their mean age was 74.5 years (SD = 5.7, range = 64-84).
  
  
  METHODS
  Thirteen impairment-level variables and 8 physical performance variables were measured. Measurements were taken on two consecutive days and again a week later on the corresponding two consecutive days. Reliability and stability were assessed using analysis of variance and intraclass correlation coefficients (ICCs).
  
  
  RESULTS
  Test-retest reliability (ICCs) of variables ranged from .69 (hamstring muscle length) to .97 (lumbar flexion). Intraclass correlation coefficients were .85 or greater for 10 of the variables.
  
  
  CONCLUSIONS
  The results suggest that in the early and middle stages of PD, many of the measures of impairment and physical performance are relatively stable.
authors.affiliation: Graduate Program in Physical Therapy, Duke University, Durham, NC 27710, USA.
authors.forename: M
authors.initials: M
authors.lastname: Schenkman
authors.forename: T M
authors.initials: TM
authors.lastname: Cutson
authors.forename: M
authors.initials: M
authors.lastname: Kuchibhatla
authors.forename: J
authors.initials: J
authors.lastname: Chandler
authors.forename: C
authors.initials: C
authors.lastname: Pieper
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis*; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D013131:Spine / Q000502:physiology; D013997:Time Factors