Impact of Fatigue on Quality of Life in People With Parkinson’s Disease

PURPOSE: Parkinson’s disease (PD) is a common neurodegenerative disorder in older adults, and fatigue is a common and debilitating symptom in people with PD (Yoshii, Takahashi, Kumazawa, & Kobori, 2006). It may increase the burden of living with the disease and negatively affect not only their daily lives but also their social lives. However, there have not been enough studies investigating the impact of fatigue on quality of life (QOL) for people with PD. The purpose of this study was to explore the impact of fatigue on QOL for people with PD.

DESIGN AND METHOD: In this descriptive study, participants were 24 people with PD (14 women, 10 men; M age 69.1 ± 8.5 yr; M disease duration 8.8 ± 5.6 yr). This study was approved by the institutional review board of Kitasato University Hospital, and informed consent was obtained from each participant. Data were collected by structured interview using multiple questionnaires. Fatigue was assessed with the Multidimensional Fatigue Inventory (MFI), a 20-item instrument with scores ranging from 20 (absence of fatigue) to 100 (maximum fatigue). QOL was assessed with the Parkinson’s Disease Quality of Life Questionnaire (PDQ–39); total scores range from 0 (never have difficulty) to 100 (always have difficulty), with lower scores reflecting better QOL. After the interview, motor function–related PD symptoms were assessed by a therapist using Part 3 of the Unified Parkinson’s Disease Rating Scale (UPDRS–III); higher scores indicate greater impact of PD symptoms. The relationships between fatigue, QOL, and motor function were analyzed with Spearman’s correlation coefficient. A multiple regression model was used with PDQ–39 as a dependent variable and MFI and UPDRS–III as independent variables. Significance was set at p < .05.

RESULTS: M MFI score was 63.3 ± 12.4, M PDQ–39 score was 40.2 ± 20.3, and M UPDRS score was 45.5 ± 25.9. PDQ–39 scores were significantly correlated with MFI scores (r = .78, p < .05) and UPDRS scores (r = .75, p < .05). The multiple regression model indicated that MFI score was significantly associated with PDQ–39 score independently from UPDRS score, F(2, 21) = 35.99, p < .001; adjusted R ² = 0.752. In other words, higher fatigue was shown to relate to higher QOL (regression coefficient of MFI = 0.9064, p < 0.001).

CONCLUSION: Our hypothesis was supported that the symptom of fatigue is an effector for QOL in people with PD independently from motor function–related PD symptoms. Fatigue includes diverse domains: physical fatigue, reduced activity, reduced motivation, and mental fatigue (Lou, Kearns, Oken, Sexton, & Nutt, 2001). Future study is necessary to investigate how each domain of fatigue is related to QOL in people with PD.

IMPACT STATEMENT: The results from our study suggest that fatigue is a significant contributor to poor OQL, and intervention to improve fatigue is recommended to improve QOL for people with PD.

References

Lou, J. S., Kearns, G., Oken, B., Sexton, G., & Nutt, J. (2001). Exacerbated physical fatigue and mental fatigue in Parkinson’s disease. Movement Disorders, 16, 190–196. https://doi.org/10.1002/mds.1042

Yoshii, F., Takahashi, H., Kumazawa, R., & Kobori, S. (2006). Parkinson’s disease and fatigue. Journal of Neurology, 253, 48–53. https://doi.org/10.1007/s00415-006-7011-6