title: Construct validity of the stroke-specific quality of life questionnaire in ischemic stroke patients.
abstract: OBJECTIVE
  To investigate the construct validity of the commonly used 8- and 12-domain versions of the Stroke-Specific Quality of Life (SS-QOL) with a first-order factor model. The better-fitted version was further evaluated by a second-order factor structure model in order to determine whether a summary score is justified.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Outpatient stroke clinic.
  
  
  METHODS
  Patients (N=388) with ischemic stroke.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  The SS-QOL. We first conducted confirmatory factor analysis (CFA) to evaluate the construct validity of the first-order 8- or 12-domain versions of the SS-QOL. The better-fitted version was then validated by investigating the second-order health-related quality of life (HRQOL) factor.
  
  
  RESULTS
  The 12-domain version, but not the 8-domain version, had sufficient goodness of fit (χ(2)=2041.7, df=1061, χ(2)/df=1.9, comparative fit index [CFI]=0.98, Tucker-Lewis index [TLI]=0.98, and root mean square error of approximation=0.05). All items of the 12-domain version showed acceptable factor loadings (>0.40) and were retained. Furthermore, the second-order CFA fit indices of the 12 domains were acceptable (χ(2)=2630.3, df=1115, χ(2)/df=2.4, CFI=0.97, TLI=0.97, root mean square error of approximation=0.06), indicating that a summary score was justified for representing the overall status of HRQOL.
  
  
  CONCLUSIONS
  Our results show that the construct validity of the 12-domain SS-QOL is well supported for measuring HRQOL in ischemic stroke patients. Thus, we recommend the 12-domain version of the SS-QOL for use in capturing the multiple impacts of stroke as well as overall HRQOL status on the basis of patients' perspectives.
authors.affiliation: School of Occupational Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: I-Ping
authors.initials: IP
authors.lastname: Hsueh
authors.forename: Jiann-Shing
authors.initials: JS
authors.lastname: Jeng
authors.forename: Yen
authors.initials: Y
authors.lastname: Lee
authors.forename: Ching-Fan
authors.initials: CF
authors.lastname: Sheu
authors.forename: Ching-Lin
authors.initials: CL
authors.lastname: Hsieh
mesh_terms: D000368:Aged; D002545:Brain Ischemia / Q000523:psychology*; D015331:Cohort Studies; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011594:Psychometrics; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D020521:Stroke / Q000523:psychology*; D011795:Surveys and Questionnaires