Identifying and responding to fatigue and apathy in Parkinson's disease: a review of current practice.

Introduction : Fatigue and apathy are two key non-motor symptoms in Parkinson's disease (PD), with documented negative impact on Quality of life (QoL) and a frequent burden for caregivers. Areas covered : In this review, the authors comment on the latest pathophysiology, clinical phenomenology, the most frequently used scales for fatigue and apathy in PD with a focus on available therapeutic strategies. Expert opinion :The identification of fatigue and apathy in PD is mainly hampered by the lack of a clear consensus on these subjective symptoms. The pathophysiological processes remain unclear, and the large variation in prevalence is likely due to the heterogeneous PD populations and the lack of an enriched cohort of people with fatigue and/or apathy as main symptoms. Treatment strategies, and especially level 1 evidence for specific treatments for fatigue and apathy in PD, remain scarce. The best evidence to date is doxepin, rasagiline and levodopa infusion therapy (for fatigue), and rivastigmine (for apathy). Further efforts should be made to properly identify these two major symptoms in PD, to correctly detect those who may benefit most from tailored personalized interventions.