Fatigue in early Parkinson's disease. Minor inconvenience or major distress?

Background and purpose: Although fatigue is recognized as a common and debilitating symptom in patients with Parkinson's disease (PD), little is known on how and when this symptom emerges during disease progression. The aim of the study was to explore the presence and severity of fatigue in patients with PD at the time of diagnosis, before dopaminergic treatment has been instituted.

Methods: The present study is part of the Norwegian ParkWest project, a large cohort study of patients with incident PD in Norway. PD was diagnosed according to the Gelb criteria. The study population comprised 199 patients with untreated, newly diagnosed PD and 172 control subjects, matched for gender and age. Fatigue was measured by the Fatigue Severity Scale (FSS).

Results: Fifty-five percent of the patients with PD had clinical significant fatigue (FSS > 4), compared with about 20% of the controls (RR = 2.9). The mean score in patients on the FSS was 4.4 (SD 1.7) and in controls 3.1 (SD 1.3). In addition, there were highly significant differences between patients and controls in each of the nine FSS items. In a regression analysis, only the Montgomery and Åsberg Depression Rating Scale and Unified Parkinson's Disease Rating Scale-Activities of Daily Living scores were significantly associated with fatigue. There was no correlation between fatigue and cognitive impairment and hypersomnia.

Conclusion: Fatigue is a common symptom in PD, also in patients with early, untreated disease, and it has a negative impact on these patients' activity of daily living. Also in early PD, fatigue is an important consideration in the management of patients with the disease.