The 39 item Parkinson's disease questionnaire (PDQ-39) revisited: implications for evidence based medicine.

ABSTRACT:

Background

The 39 item Parkinson's disease questionnaire (PDQ-39) is the most widely used patient reported rating scale in Parkinson's disease. However, several fundamental measurement assumptions necessary for confident use and interpretation of the eight PDQ-39 scales have not been fully addressed.

Methods

Postal survey PDQ-39 data from 202 people with Parkinson's disease (54% men; mean age 70 years) were analysed regarding psychometric properties using traditional and Rasch measurement methods.

Results

Data quality was good (mean missing item responses, 2%) and there was general support for the legitimacy of summing items within scales without weighting or standardisation. Score reliabilities were adequate (Cronbach's alpha 0.72-0.95; test-retest 0.76-0.93). The va

SUBMITTER: Hagell P 

PROVIDER: S-EPMC2117601 | biostudies-literature | 2007 Nov

REPOSITORIES: biostudies-literature