Measuring symptom change in patients with Parkinson's disease

Background: the 39-item Parkinson's disease questionnaire (PDQ-39) is more sensitive to functional change than other measures of health and disability . Aim: to determine the ability of this scale to change over time and the con current validity of some of its subscales. Methods: we assessed a cohort of 67 Parkinson's patients for 18 months, usi ng the PDQ-39, the GHQ-28 general health questionnaire and the Office of Po pulation and Census Surveys disability instrument. Results: the Office of Population and Census Surveys disability instrument and GHQ-28 recorded no significant change, but the PDQ-39 showed marked cha nges in levels of functioning. We also analysed changes on the PDQ-39 subsc ales as well as concurrent validity data for several subscales. This showed concurrent validity with the Beck depression and anxiety inventories, the Barthel index and the Royal Postgraduate Medical School severity scale. The re was a high level of concurrent validity for all comparisons except for t he Barthel index. Conclusion: the PDQ-39 is a sensitive tool for monitoring change in patient s with Parkinson's disease. It has high levels of concurrent validity with established measures of mood and motor function.