title: Respondent burden and patient-perceived validity of the PDQ-39.
abstract: OBJECTIVE
  To evaluate the respondent burden and patient-perceived content validity of the Parkinson's disease (PD)-specific health status questionnaire PDQ-39, and the linguistic validity of its revised Swedish version.
  
  
  METHODS
  Eighteen PD patients completed the revised Swedish version of the PDQ-39. Respondent burden was assessed by recording the time taken to complete the questionnaire. Content and linguistic validity was evaluated qualitatively.
  
  
  RESULTS
  Patients with mild, moderate and advanced PD needed a mean time of 9.5, 11.3 and 20.1 min, respectively, to complete the PDQ-39. One-third of the patients identified irrelevant items and 50% identified important health-related areas that were missing. Revisions had eliminated previous linguistic problems with the Swedish PDQ-39.
  
  
  CONCLUSIONS
  Undue respondent burden challenged the appropriateness of the PDQ-39 among patients with more advanced disease. Overall content validity was acceptable but compromised by lack of important content areas. Observations supported the linguistic validity of the revised Swedish PDQ-39.
authors.affiliation: Department of Health Sciences, Lund University, Lund, Sweden.
authors.forename: M-Y
authors.initials: MY
authors.lastname: Kim
authors.forename: A
authors.initials: A
authors.lastname: Dahlberg
authors.forename: P
authors.initials: P
authors.lastname: Hagell
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000523:psychology*; D017060:Patient Satisfaction; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D013997:Time Factors