title: The Intra- and Inter-Rater Reliability of an Instrumented Spasticity Assessment in Children with Cerebral Palsy.
abstract: OBJECTIVE
  Despite the impact of spasticity, there is a lack of objective, clinically reliable and valid tools for its assessment. This study aims to evaluate the reliability of various performance- and spasticity-related parameters collected with a manually controlled instrumented spasticity assessment in four lower limb muscles in children with cerebral palsy (CP).
  
  
  METHODS
  The lateral gastrocnemius, medial hamstrings, rectus femoris and hip adductors of 12 children with spastic CP (12.8 years, ±4.13 years, bilateral/unilateral involvement n=7/5) were passively stretched in the sagittal plane at incremental velocities. Muscle activity, joint motion, and torque were synchronously recorded using electromyography, inertial sensors, and a force/torque load-cell. Reliability was assessed on three levels: (1) intra- and (2) inter-rater within session, and (3) intra-rater between session.
  
  
  RESULTS
  Parameters were found to be reliable in all three analyses, with 90% containing intra-class correlation coefficients >0.6, and 70% of standard error of measurement values <20% of the mean values. The most reliable analysis was intra-rater within session, followed by intra-rater between session, and then inter-rater within session. The Adds evaluation had a slightly lower level of reliability than that of the other muscles.
  
  
  CONCLUSIONS
  Limited intrinsic/extrinsic errors were introduced by repeated stretch repetitions. The parameters were more reliable when the same rater, rather than different raters performed the evaluation. Standardisation and training should be further improved to reduce extrinsic error when different raters perform the measurement. Errors were also muscle specific, or related to the measurement set-up. They need to be accounted for, in particular when assessing pre-post interventions or longitudinal follow-up. The parameters of the instrumented spasticity assessment demonstrate a wide range of applications for both research and clinical environments in the quantification of spasticity.
authors.affiliation: Clinical Motion Analysis Laboratory, University Hospital Leuven, Leuven, Belgium; Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.
authors.forename: Simon-Henri
authors.initials: SH
authors.lastname: Schless
authors.affiliation: Clinical Motion Analysis Laboratory, University Hospital Leuven, Leuven, Belgium; Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.
authors.forename: Kaat
authors.initials: K
authors.lastname: Desloovere
authors.affiliation: Department of Mechanical Engineering, KU Leuven, Leuven, Belgium.
authors.forename: Erwin
authors.initials: E
authors.lastname: Aertbeliën
authors.affiliation: Clinical Motion Analysis Laboratory, University Hospital Leuven, Leuven, Belgium; Departments of Development and Regeneration, KU Leuven, Leuven, Belgium; Department of Orthopaedic Medicine, University Hospital Leuven, Leuven, Belgium.
authors.forename: Guy
authors.initials: G
authors.lastname: Molenaers
authors.affiliation: Clinical Motion Analysis Laboratory, University Hospital Leuven, Leuven, Belgium.
authors.forename: Catherine
authors.initials: C
authors.lastname: Huenaerts
authors.affiliation: Clinical Motion Analysis Laboratory, University Hospital Leuven, Leuven, Belgium; Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.
authors.forename: Lynn
authors.initials: L
authors.lastname: Bar-On
mesh_terms: D000293:Adolescent; D002547:Cerebral Palsy / Q000175:diagnosis* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D004576:Electromyography / Q000592:standards*; D005260:Female; D006801:Humans; D007866:Leg / Q000294:innervation / Q000503:physiopathology; D009128:Muscle Spasticity / Q000175:diagnosis* / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000503:physiopathology*; D015588:Observer Variation; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D019415:Torque