title: Can the Dyskinesia Impairment Scale be used by inexperienced raters? A reliability study.
abstract: BACKGROUND
  The Dyskinesia Impairment Scale (DIS) is a new scale for measuring dystonia and choreoathetosis in dyskinetic Cerebral Palsy (CP). Previously, reliability of this scale has only been assessed for raters highly experienced in discriminating between dystonia and choreoathetosis.
  
  
  OBJECTIVE
  The aims of this study are to examine the reliability of the DIS used by inexperienced raters, new to discriminating between dystonia and choreoathetosis and to determine the effect of clinical expertise on reliability.
  
  
  METHODS
  Twenty-five patients (17 males; 8 females; age range 5-22 years; mean age = 13 years 6 months; SD = 5 years 4 months) with dyskinetic CP were filmed with the DIS standard video protocol. Two junior physiotherapists (PTs) and three senior PTs, all of whom were new to discriminating between dystonia and choreoathetosis, were trained in scoring the DIS. Afterward, they independently scored all patients from the video recordings using the DIS. Reliability was assessed by (1) Intraclass Correlation Coefficient (ICC), (2) Standard Error of Measurement (SEM) and Minimal Detectable Difference (MDD) and (3) Cronbach's alpha for internal consistency.
  
  
  RESULTS
  Interrater reliability for the total DIS, and for the dystonia and choreoathetosis subscales was good for the junior PTs and moderately high to excellent for the senior PTs. SEM and MDD values for the total DIS were 6% and 15% respectively for the junior PTs and 4% and 12% respectively for the senior PTs. Cronbach's alpha ranged between 0.87 and 0.95 for the junior PTs and between 0.76 and 0.93 for the senior PTs.
  
  
  CONCLUSIONS
  Reliability of the DIS scores for the inexperienced junior and senior PTs was sufficient in comparison with scores from the experienced raters in the previous study, indicating that the DIS can be used by inexperienced PTs new to discriminating between dystonia and choreoathetosis, and also that its reliability is not dependent on clinical expertise. However, based on the measurement errors and questionnaire data, familiarity with operational definitions of dystonia and choreoathetosis is crucial to improve scoring reliability.
authors.affiliation: Katholieke Universiteit Leuven, Department of Rehabilitation Sciences, Belgium; Dienstencentrum GID(t)S, Dominiek Savio Institute, Belgium. Elegast.Monbaliu@faber.kuleuven.be
authors.forename: Elegast
authors.initials: E
authors.lastname: Monbaliu
authors.forename: Els
authors.initials: E
authors.lastname: Ortibus
authors.forename: Peter
authors.initials: P
authors.lastname: Prinzie
authors.forename: Bernard
authors.initials: B
authors.lastname: Dan
authors.forename: Josse
authors.initials: J
authors.lastname: De Cat
authors.forename: Paul
authors.initials: P
authors.lastname: De Cock
authors.forename: Hilde
authors.initials: H
authors.lastname: Feys
mesh_terms: D000293:Adolescent; D000328:Adult; D002547:Cerebral Palsy / Q000175:diagnosis; D002648:Child; D002675:Child, Preschool; D002819:Chorea / Q000175:diagnosis; D020820:Dyskinesias / Q000145:classification / Q000175:diagnosis*; D004421:Dystonia / Q000175:diagnosis; D005260:Female; D006801:Humans; D008297:Male; D059825:Physical Therapists / Q000592:standards*; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D055815:Young Adult