Clinical characteristics of fatigued Parkinson's patients and the response to dopaminergic treatment.

BACKGROUND: Fatigue, which is commonly observed in Parkinson's disease (PD), can greatly reduce quality of life and is difficult to treat. We here aimed to investigate the prevalence and characteristics of fatigue among PD patients and to explore an effective strategy to treat PD fatigue.

METHOD: This was an observational cross-sectional study conducted in northeastern China. We examined fatigue in 222 PD patients from northeastern China using the Parkinson Fatigue Scale-16 (PFS-16). The disease severity, depression, sleep and cognitive functioning were assessed with the Hoehn & Yahr staging (H-Y stage), Unified Parkinson's Disease Rating Scale (UPDRS), Hamilton Depression Scale (HAMD), Parkinson's Disease Sleep Scale (PDSS) and Montreal Cognitive Assessment (MoCA) by interview.

RESULTS: The frequency of fatigue in PD patients was 59.46 %. Fatigued patients had longer disease durations and greater disease severity than nonfatigued patients. Additionally, fatigued PD patients scored significantly higher for all motor symptoms, except for tremor, and had more serious depressive symptoms and sleep disturbances than nonfatigued PD patients did. The sleep disturbance severity was an independent factor for fatigue. Furthermore, 43.04 % of fatigued patients taking dopaminergic drugs had fatigue remission. Depression severity was identified as an independent factor for dopaminergic drug non-responsive fatigue.

CONCLUSIONS: PD patients with severe sleep disturbances tend to suffer from fatigue. Levodopa improved fatigue only in PD patients with mild depression or no depression, implying that dopaminergic medication is required, but not sufficient, for fatigue suppression in PD patients with moderate or severe depression. Thus, restoring serotonergic neurotransmission as a combination therapy may offer a better strategy for the treatment of fatigue in these patients.