Fatigue in Parkinson's disease.

INTRODUCTION: Non-motor symptoms of Parkinson's disease (PD) have become increasingly recognized as central to the disease. These include somatic symptoms, such as pain and autonomic dysfunction (bladder dysfunction, constipation, dipahoresis and orthostatic hypotension) and behavioral problems, such as dementia, depression, fatigue, sleep disorders and psychosis. Research on fatigue has focused on its epidemiology with only a single report of a beneficial treatment trial, which used methylphenidate. AREAS COVERED: This review was made of all articles related to fatigue in Parkinson's disease arising in PUBMED. It will cover the types of fatigue, epidemiology, pathophysiology and treatment of fatigue in PD. EXPERT OPINION: Fatigue is a common and severe problem in Parkinson's disease. Virtually nothing is known about it aside from its epidemiology. It is an area greatly in need of investigation.