title: Validity and reliability of the Chinese (Singapore) version of the Parkinson's Disease Questionnaire (PDQ-39).
abstract: OBJECTIVE
  The purpose of the study was to validate the Chinese (Singapore) version of the Parkinson's Disease Questionnaire (PDQ-39CSV) and its briefer version (PDQ-8CSV).
  
  
  METHODS
  A convenience sample of Chinese-speaking Singaporeans with Parkinson's disease (PD) (n = 63) completed a questionnaire containing the PDQ-39CSV and the Chinese (Singapore) EQ-5D. A subgroup also participated in a retest and/or a focus group discussion. A priori hypotheses were tested by examining correlations between PDQ-39CSV, PDQ-8CSV and EQ-5D scores and using principal component factor analysis. Reliability was assessed using Cronbach's alpha and intra-class correlation coefficients (ICC).
  
  
  RESULTS
  Thirty-two PDQ-39CSV items correlated satisfactorily with their hypothesized dimensions (Spearman's p > or = 0.4). Factor analysis yielded a component on which all 8 PDQ-39CSV dimensions were substantially loaded (loading range: 0.53-0.89). As hypothesized, the PDQ-39CSV and PDQ-8CSV summary indices were highly correlated (Pearson's r:0.95, ICC:0.94); correlations between related PDQ and EQ-5D scores were generally strong (Spearman's p: 0.38-0.76, p < 0.001 for all). Cronbach's alpha values ranged from 0.64 to 0.90 and ICC values from 0.66 to 0.86.
  
  
  CONCLUSIONS
  This study provides preliminary evidence supporting validity and reliability of both the PDQ-39CSV and its briefer version.
authors.affiliation: Department of Pharmacy, National University of Singapore, Singapore.
authors.forename: N
authors.initials: N
authors.lastname: Luo
authors.forename: L C S
authors.initials: LC
authors.lastname: Tan
authors.forename: S C
authors.initials: SC
authors.lastname: Li
authors.forename: L K
authors.initials: LK
authors.lastname: Soh
authors.forename: J
authors.initials: J
authors.lastname: Thumboo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002681:China; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology* / Q000523:psychology; D011788:Quality of Life; D011795:Surveys and Questionnaires