Short communicationMotor and non-motor predictors of illness-related distress in Parkinson’s disease
Introduction
People with Parkinson’s disease (PD) suffer from both motor symptoms (e.g. bradykinesia, gait- and balance impairments) and non-motor symptoms (e.g. depression, anxiety, fatigue and sleep problems). A recent systematic review concluded that depression, disease severity and disability negatively influence the patient-reported impact of PD [1]. However, the reviewed studies varied regarding the included potential independent variables. For example, whereas several studies used depression as a potential contributor to patient-reported disease impact, only one study simultaneously included fatigue, depression and sleep as independent variables but not any motor aspects [1]. Here we sought to gain an improved understanding of the impact of PD by investigating associations between patient-reported illness-related distress and a wide range of motor and non-motor aspects of PD. More specifically, we aimed to explore the potential contributions of motor and non-motor aspects, separately as well as in combination.
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Participants
Data were taken from a consecutively recruited cross-sectional multicenter sample of 118 people with PD (Table 1). Exclusion criteria were participation in other ongoing studies, infections, psychiatric adverse drug reactions and clinically significant co-morbidities [2]. The study was approved by the local research ethics committees, and all participants signed informed consent.
Procedures and data collection
Patients were assessed during the “on” phase using the Unified PD Rating Scale (UPDRS) [3], the Hoehn & Yahr (HY)
Results
Bivariate associations between potential predictors and patient-reported illness-related distress are reported in Supplemental Table 1.
Among non-motor aspects of PD (model 1), five significant associations were identified, accounting for 81% of the variance in NHPD scores (Table 2). The strongest association (as assessed by the standardized regression coefficients, β) was found for pain, followed by fatigue, sleep quality, depression, and anxiety (Table 2).
Only one significant independent
Discussion
This study incorporated multidimensional motor and non-motor perspectives. Results imply that the impact of PD on patient-reported distress appears to be mainly influenced by non-motor disease aspects (e.g. fatigue, sleep and pain), while a main motor component is that of mobility rather than the underpinning PD motor symptoms per se. Mobility difficulties were in fact independently associated with distress not only when considering motor aspects in general but also when analyzing the five
Funding
The study was conducted within the BAGADILICO (the Basal Ganglia Disorders Linnaeus Consortium) research group at Lund University, Sweden. The study was supported by the Swedish Research Council, the Swedish Parkinson Foundation, the Skane County Council Research and Development Foundation, the Faculty of Medicine at Lund University, and the Swedish Parkinson Academy. MHN was partly funded by the Strategic Research Area MultiPark at Lund University, and by the Swedish Council for Working Life
Competing interests
None.
Acknowledgments
The authors want to thank the study participants for their cooperation; B. Eriksson, A. Höglund, I. Knutsson, and J. Reimer for assistance with data collection; and Drs. J. Ahlberg, N. Dizdar, H. Edwall, B. Johnels, J. Lökk, S. Pålhagen, H. Widner, and T. Willows for patient recruitment.
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