[Validation of the French language version of the Parkinson's Disease Questionnaire - PDQ-39].

After Alzheimer's disease, Parkinson's disease (PD) is the second most frequent degenerative disease of the central nervous system. The consequences of PD at the functional, social and emotional levels warrant a better understanding the patient's perceptions as measured using a specific instrument rather than restricting the medical approach to the clinical evaluation of the motor component. In 1996, we began implementation of a project to transculturally validate the single specific instrument that had been published and was available at that time: PDQ-39. The scale consists in a 39-item questionnaire enabling determination of an overall quality-of-life score and scores for 8 specific dimensions: mobility, activities of daily living, emotional well-being, stigma, social support, cognitions, communication and bodily discomfort. Eighty-nine patients taking part in an open-label study of the safety of a combination of pergolide and dopa therapy were included and followed up on D15 and after 8 weeks. The process of "Forward-Backward" translation, conducted in close liaison with the authors, enabled semantic and linguistic validation of the French language version. The content was validated by PD experts. At baseline, the patients presented quality-of-life scores that were particularly impaired for the dimensions exploring Mobility, Emotional well-being and Bodily discomfort. The main metric properties of the scale were confirmed. The PDQ-39 scores were closely correlated with the related concepts investigated by generic scale, SF-36. The PDQ-39 scores were correlated with the "Mental and Mood Status", "Everyday Activities" and "Motor Status" dimensions determined by the UPDRS. The reliability, expressed by Cronbach coefficients alpha, showed strong consistency of the instrument, very similar to the data for the original version. In contrast to what was observed with SF-36, the scale was particularly sensitive to clinical changes. The initial results make PDQ-39 a precious tool for the optimization of management of patients presenting with PD.