Non-motor symptoms of Parkinson's disease: the patient's perspective.

Parkinson's disease (PD) can be manifested in many different ways. Although motor dysfunction represents the best characterised of the symptoms, the non-motor symptoms (NMS) of the condition can be equally disabling for people. These have been highlighted as being an issue of particular importance by people with PD. A comprehensive postal survey of members of the charity Parkinson's UK took place in 2008. This resulted in returns from 10,101 people with PD. The self-completed Non-Motor Questionnaire (NMSQuest) and quality of life scale (PDQ-8) were contained within the survey. The results showed that the percentage of people with PD experiencing NMS increased with the duration of the disease. However, people who had the younger onset form of the condition reported a greater impact of NMS, particularly in the areas of memory, depression and sleep function. There is an inverse correlation between NMS and (PDQ-8 scale). A significant number of people with PD reported that they experienced problems with olfaction, taste, nocturia and constipation prior to diagnosis and these may help to serve as a future biomarker for the condition. Although our understanding of PD-associated NMS has increased considerably in the recent past, there is still a general lack of awareness of the importance of NMS for people with PD. Further research is required to identify the best treatments that should be employed to address them.