Non-motor parkinsonism.

Recent years have brought increased awareness of and attention to the non-motor aspects of Parkinson's disease. Non-motor features encompass a surprisingly broad clinical spectrum that includes sensory dysfunction, behavioral abnormalities, autonomic impairment, sleep disturbances, and fatigue. Some of these features, such as impaired olfaction, REM sleep behavior disorder, and constipation, may develop long before the classic motor features of Parkinson's disease make their appearance, while others emerge in concert with disease progression. The early emergence of some non-motor features presents diagnostic opportunities, while the dopa-unresponsiveness of others poses treatment challenges, especially in the advanced stages of the disease.