Dataset Information

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 validity of the current grouping of items into scales was not supported by scaling success rates (mean 56.2%), or factor and Rasch analyses. All scales represented more health problems than that experienced by the sample (mean floor effect 15%) and showed compromised score precision towards the less severe end.

Conclusions

Our results provide general support for the acceptability and reliability of the PDQ-39. However, they also demonstrate limitations that have implications for the use of the PDQ-39 in clinical research. The grouping of items into scales appears overly complex and the meaning of scale scores is unclear, which hampers their interpretation. Suboptimal targeting limits measurement precision and, therefore, probably also responsiveness. These observations have implications for the role of the PDQ-39 in clinical trials and evidence based medicine. PDQ-39 derived endpoints should be interpreted and selected cautiously, particularly regarding small but clinically important effects among people with less severe problems.

SUBMITTER: Hagell P

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

REPOSITORIES: biostudies-literature

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Publications

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

Hagell Peter P Nygren Carita C

Journal of neurology, neurosurgery, and psychiatry 20070418 11

<h4>Background</h4>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.<h4>Methods</h4>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 mea ...[more]

PMID: 17442762

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Project description:BackgroundResearch addressing perceptions of housing in people with Parkinson's disease (PD) is rare, and existing instruments capturing perceived aspects of housing are rarely used. Perceived housing comprises of several domains and is associated with health in general older populations. One such domain is meaning of home, captured by the Meaning of Home Questionnaire (MOH). The aim of this study was to evaluate psychometric properties of the MOH among people with PD.Materials and methodsThe MOH was administrated to 245 participants with PD (mean age = 69.9 years; mean PD duration = 9.7 years). The instrument consisted of four sub-scales with 28 items, each with 11 response options (strongly disagree = 0; strongly agree = 10). We evaluated data quality, structural validity (factor analysis), construct validity (i.e., testing correlations with relevant constructs according to pre-defined hypotheses), corrected item total correlations, floor and ceiling effects and internal consistency.ResultsThe data quality was high (0-1.2% missing data). The exploratory factor analysis suggested removal of five items and revealed three new factors; "My home is my castle", "My home is my prison" and "My home is my social hub". The 23-item MOH showed statistically significant correlations with life satisfaction, usability and ADL dependence, while not correlated with number of environmental barriers. These findings were largely as hypothesised, thus supporting construct validity (both convergent and discriminant). The corrected item total correlations were >0.3 for all items and the internal consistency was >0.70 for all sub-scales. No floor or ceiling effects were reported except for the sub-scale "My home is my castle" (ceiling effect = 15.6%).ConclusionsThe 23-item MOH version with three new sub-scales is sufficiently reliable and valid for use in PD populations. This paves the way for further research of meaning of home among people with PD, using the 23-item MOH version.

Dataset Information

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

Background

Methods

Results

Conclusions

Publications

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

Similar Datasets

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