Quality of life and Parkinson's disease: Philippine translation and validation of the Parkinson's disease questionnaire

The 39-item Parkinson's Disease Quality of Life Questionnaire (PDQ-39) is the most widely used self-administered questionnaire assessing the quality of life of Parkinson's disease (PD) patients. We translated the PDQ-39 into the Filipino language as the Philippine-PDQ-39 (P-PDQ-39) and used it to assess the quality of life of Filipino patients with PD. The original PDQ-39 was translated into Filipino using forward and backward translation by independent bilingual translators and used among 100 consecutively sampled PD patients. Baseline demographic data, disease duration and levodopa equivalent dose were collected. Internal consistency was measured using Chronbach's α. The following rating scales and questionnaires were correlated with P-PDQ-39 through Pearson's correlation coefficient to assess construct validity: modified Hoehn & Yahr Stage, Hospital Anxiety and Depression Scale-Pilipino (HADS-P), Unified Parkinson's Disease Rating Scale (UPDRS) Parts I-III, and Non-motor symptom Assessment Scale for Parkinson's Disease (NMSS). The mobility and activities of daily living domains of the P-PDQ-39 were well correlated with the Hoehn & Yahr stage of the patients and the UPDRS II and III scores emphasizing the value of motor symptoms in quality of life. Non motor symptoms in PD were also important determinants of quality of life as demonstrated in the correlation of HADS-P and NMSS Total scores with the P-PDQ 39 domains. The P-PDQ-39 is a valid assessment tool for assessing the quality of life of Filipino-speaking PD patients.