Beyond tremor and rigidity: non-motor features of Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disease and primarily considered as a movement disorder defined by the presence of motor symptoms, such as bradykinesia, tremor and rigidity. However, it is nowadays widely accepted that PD is associated with a wide variety of non-motor features, which affect the vast majority of patients during the course of the disease and may even precede the onset of motor symptoms. The spectrum of these non-motor disturbances is very broad and comprises neuropsychiatric conditions, such as depression, dementia and hallucinations, as well as autonomic, sensory and sleep disorders. Physicians need to be aware of these non-motor features, since they have substantial impact on the health-related quality of life of PD patients, even ahead of motor symptoms. This article aims to provide an overview of frequently observed non-motor features in PD and discusses prospects and limitations of currently available options for symptomatic treatment of these disturbances.