Fatigue in patients with Parkinson’s disease: Motor and Non-motor Clinical Associations

Objective: Fatigue is one of the common non-motor symptoms of Parkinson’s disease (PD). In this study, we aimed to investigate the prevalence of fatigue in PD patients and to determine the fatigue-related demographic, motor and non-motor disease characteristics.

Materials and Methods: One hundred seventy-eight idiopathic PD patients were enrolled in the study (mean age 64.8±10.8 years). Demographic data and disease-related motor and non-motor clinical characteristics were recorded and total daily levodopa equivalent dose (LED) was calculated. Modified Hoehn and Yahr Staging (mHY), 'Unified Parkinson's Disease Rating Scale' (UPDRS) part II and III, Parkinson Fatigue Scale (PFS), Mini-Mental State Examination and semi-structured non-motor symptom questionnaire were used to assess the patients. Patients were divided into two groups according to the score of PFS3.3 as PD without fatigue, PFS≥3.3 as PD with fatigue. Then we compared the disease characteristics between the two groups. Bivariate associations were analyzed using the chi-square and the independent samples t-test.

Results: The fatigue prevalence was 48.9% in all PD patients. There was no significant difference between groups regarding age and the duration of disease, but the mean LED in PD patients with fatigue was significantly higher than without fatigue (p=0.011). Parkinson’s disease stage, activities of daily living and disease severity were not different between two groups. Orthostatic hypotension and sleep disturbances such as restless legs syndrome (RLS) and REM sleep behavior disorder (RBD) were significantly frequent in PD group with fatigue (p=0.02, p=0.004, p=0.005 respectively).

Conclusion: Fatigue affects about 50% of PD patients. Association of fatigue and non-motor symptoms may reflect the dopaminergic and non-dopaminergic underlying pathologic mechanisms.