title: Reliability of center of pressure measures for assessing the development of sitting postural control in infants with or at risk of cerebral palsy.
abstract: OBJECTIVE
  To establish the test-retest reliability of linear and nonlinear measures, including intra- and intersession reliability, when used to analyze the center of pressure (COP) time series during the development of infant sitting postural control in infants with or at risk for cerebral palsy (CP).
  
  
  METHODS
  Longitudinal study.
  
  
  METHODS
  University hospital laboratory.
  
  
  METHODS
  Infants with or at risk for CP (N=18; mean age ± SD at entry into the study, 13.7±3.6mo).
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Infant sitting COP data were recorded for 3 trials at each session (2 sessions for each month within 1 week) for 4 consecutive months. The linear COP parameters of the root mean square, the range of sway for both the anterior-posterior and the medial-lateral directions, and the sway path were calculated. In addition, the nonlinear parameters of approximate entropy, Lyapunov exponent (LyE), and the correlation dimension for both directions were also calculated. Intra- and intersession reliability was computed by the intraclass correlation coefficient (ICC).
  
  
  RESULTS
  Regarding nonlinear measures, LyE showed high intra- and intersession ICC values in comparison with all other parameters evaluated. Intrasession and intersession reliability increased overall in the last 2 months of data collection and as sitting posture improved.
  
  
  CONCLUSIONS
  Our results suggested that the methodology presented is a reliable way of examining the development of sitting postural control in infants with or at risk for CP, and the reliability results generally parallel values found in sitting postural behavior in typical infants. Therefore, this methodology may be helpful in examining efficacy of therapy protocols directed at advancing sitting postural control in infants with motor developmental delays.
authors.affiliation: University of Nebraska at Omaha, 68182-0216, USA.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Kyvelidou
authors.forename: Regina T
authors.initials: RT
authors.lastname: Harbourne
authors.forename: Valerie K
authors.initials: VK
authors.lastname: Shostrom
authors.forename: Nicholas
authors.initials: N
authors.lastname: Stergiou
mesh_terms: D002547:Cerebral Palsy / Q000175:diagnosis* / Q000534:rehabilitation*; D002658:Developmental Disabilities / Q000175:diagnosis / Q000534:rehabilitation; D005260:Female; D006785:Hospitals, University; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D015588:Observer Variation; D026741:Physical Therapy Modalities; D004856:Postural Balance; D015203:Reproducibility of Results