The association between objectively measured physical activity, depression, cognition, and health-related quality of life in Parkinson's disease.

Background: Lower levels of physical activity are associated with lower Health-Related Quality of Life (HRQoL) in Parkinson's disease (PD). We evaluated the influence of quantitative physical activity parameters among other (disease-related) features representing other domains of the WHO International model for classification of Function, Disability, and Health (ICF) on HRQoL in PD.

Methods: Home-based movement data (DynaPort MiniMod) was collected in 47 PD patients. Nine stepwise regression models were calculated, with consecutive outcome variables: Parkinson's Disease Questionnaire (PDQ) Summary Index (SI), PDQ-Mobility, PDQ-Activities of Daily Living (ADL). Demographic variables, disease-specific features, and quantitative physical activity parameters, were included as predicting variables in all analyses. The following three physical activity parameters were alternately included for both sedentary and active episodes: 'percentage' of 24 h spent within these episodes, 'number of bouts', and 'mean bout lengths' (MBL).

Results: Depression and 'Total Energy Expenditure' were the main predictors of overall HRQoL (PDQ-SI), independent of the permutation of activity parameters. The same parameters predicted the PDQ-Mobility score. However, this result was altered when 'MBL' parameters were included into the model, 'MBL' of sedentary episodes additionally predicted HRQoL-Mobility. The PDQ-ADL score was associated with demographic, motor, and non-motor variables including cognitive status. After exclusion of demented PD patients, older age and cognitive impairment no longer constrained HRQoL-ADL.

Discussion: For the first time, we showed the influence of objective, home-based measured physical activity among depression and cognition on HRQoL in PD. This suggests that a multifactorial treatment approach would be most successful to increase HRQoL in PD.