title: Item hierarchy-based analysis of the Rivermead Mobility Index resulted in improved interpretation and enabled faster scoring in patients undergoing rehabilitation after stroke.
abstract: OBJECTIVE
  To enable improved interpretation of the total score and faster scoring of the Rivermead Mobility Index (RMI) by studying item ordering or hierarchy and formulating start-and-stop rules in patients after stroke.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Rehabilitation center in the Netherlands; stroke rehabilitation units and the community in the United Kingdom.
  
  
  METHODS
  Item hierarchy of the RMI was studied in an initial group of patients (n=620; mean age ± SD, 69.2±12.5y; 297 [48%] men; 304 [49%] left hemisphere lesion, and 269 [43%] right hemisphere lesion), and the adequacy of the item hierarchy-based start-and-stop rules was checked in a second group of patients (n=237; mean age ± SD, 60.0±11.3y; 139 [59%] men; 103 [44%] left hemisphere lesion, and 93 [39%] right hemisphere lesion) undergoing rehabilitation after stroke.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Mokken scale analysis was used to investigate the fit of the double monotonicity model, indicating hierarchical item ordering. The percentages of patients with a difference between the RMI total score and the scores based on the start-and-stop rules were calculated to check the adequacy of these rules.
  
  
  RESULTS
  The RMI had good fit of the double monotonicity model (coefficient H(T)=.87). The interpretation of the total score improved. Item hierarchy-based start-and-stop rules were formulated. The percentages of patients with a difference between the RMI total score and the score based on the recommended start-and-stop rules were 3% and 5%, respectively. Ten of the original 15 items had to be scored after applying the start-and-stop rules.
  
  
  CONCLUSIONS
  Item hierarchy was established, enabling improved interpretation and faster scoring of the RMI.
authors.affiliation: Amsterdam Rehabilitation Research Center, Reade, Amsterdam, The Netherlands. l.roorda@reade.nl
authors.forename: Leo D
authors.initials: LD
authors.lastname: Roorda
authors.forename: John R
authors.initials: JR
authors.lastname: Green
authors.forename: Annemieke
authors.initials: A
authors.lastname: Houwink
authors.forename: Pam J
authors.initials: PJ
authors.lastname: Bagley
authors.forename: Jane
authors.initials: J
authors.lastname: Smith
authors.forename: Ivo W
authors.initials: IW
authors.lastname: Molenaar
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Geurts
mesh_terms: D000203:Activities of Daily Living / Q000145:classification*; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D009426:Netherlands; D017063:Outcome Assessment, Health Care; D011379:Prognosis; D011594:Psychometrics; D020127:Recovery of Function; D012047:Rehabilitation Centers; D018570:Risk Assessment; D012720:Severity of Illness Index; D012737:Sex Factors; D012959:Socioeconomic Factors; D020521:Stroke / Q000175:diagnosis; D000071939:Stroke Rehabilitation; D013647:Task Performance and Analysis; D013997:Time Factors