Validity, Reliability, and Insights from Applying the McGill Quality of Life Questionnaire to People Living with Parkinson's Disease (MQoL-PD).

Existing quality-of-life instruments for Parkinson's disease (PD) may not fully assess quality of life (QoL) for people with PD in a holistic and multidimensional manner. This study examines the subscale structure, validity, and internal-consistency reliability of the McGill Quality of Life (MQoL) Questionnaire in a sample of people with PD. This cross-sectional study evaluates the MQoL-PD by using Cronbach's alpha and principal components analysis. A total of 81 consenting people with PD from a tertiary care outpatient clinic were studied. Scores were tabulated for the motor Unified Parkinson's Disease Rating Scale (mUPDRS), the Short Form Health Survey (SF-36), the Parkinson's Disease Questionnaire (PDQ-39), the MQoL Single-Item Scale (MQoL-SIS), and the MQoL Questionnaire (MQoL). Cronbach's alpha for the MQoL-PD was: physical symptoms, 0.83; psychological symptoms, 0.59; and existential/support symptoms, 0.76. Important contributors to QoL in PD include mobility, bowel and bladder function, fatigue, and pain. The MQoL Questionnaire is a valid and reliable measure of physical, psychological, and existential/support symptoms for people with PD.