The Effect of Non-motor Symptoms on Quality of Life in Parkinson’s Disease

Parkinson’s disease (PD) affects about 1–2% of the population over 65 years of age and up to 3–5% of people 85 years of age and older. As the average age of the population increases, the prevalence of PD can be expected to rise. There is increasing awareness that the non-motor symptoms (NMS) of PD significantly contribute to the overall burden of the disease, which determines quality of life (QoL). With this in mind, it is essential to optimise the management of all aspects of PD. NMS (see Table 1) include neuropsychiatric complications, autonomic disorders, sleep disturbances and sensory symptoms. NMS affect the majority of patients during their illness and, although NMS correlate strongly with advancing disease, they may precede the onset of motor symptoms by a number of years. It is increasingly recognised that NMS create a significant burden for people with PD and affect QoL to a greater extent than motor features. Without careful attention, NMS may remain undiagnosed and untreated. A recent international survey showed that up to 62% of NMS in PD might remain undeclared to healthcare professionals because patients are either embarrassed or unaware that their symptoms are linked to PD. Using a screening tool can help to identify the problem. For example, in a study using the NMS Questionnaire (NMSQ), PD patients reported nine to 12 different NMS in their clinic visit, many of which had not been discussed with the doctor before being flagged by the NMSQ.