QUALITY-OF-LIFE IN PATIENTS WITH PARKINSONS-DISEASE - DEVELOPMENT OF A QUESTIONNAIRE

Objectives-To develop and test a questionnaire for measuring quality o f life in patients with Parkinson's disease. Methods-An item pool was developed based on the experience of patients with Parkinson's disease and of neurologists; medical literature on the problems of patients w ith Parkinson's disease; and other quality of life questionnaires. To reduce the item pool, 13 patients identified items that were a problem to them and rated their importance. Items which were most often chose n and rated most important were included in the Parkinson's disease qu ality of life questionnaire (PDQL). The PDQL consists of 37 items. To evaluate the discriminant validity of the PDQL three groups of severit y of disease were compared. To test for convergent validity, the score s of the PDQL were tested for correlation with standard indices of qua lity of life. Results-The PDQL was filled out by 384 patients with Par kinson's disease. It consisted of four subscales: parkinsonian symptom s, systemic symptoms, emotional functioning, and social functioning. T he internal-consistency reliability coefficients of the PDQL subscales were high (0.80-0.87). Patients with higher disease severity had sign ificantly lower quality of life on all PDQL subscales (P < 0.05). Almo st all PDQL subscales correlated highly (P < 0.001) with the correspon ding scales of the standard quality of life indices. Conclusion-The PD QL is a relevant, reliable, and valid measure of the quality of life o f patients with Parkinson's disease.