Quantitation of non-motor symptoms in Parkinson's disease

Disabling non-motor symptoms (NMS) associated with Parkinson's disease (PD), such as dementia and loss of balance, do not respond well to levodopa therapy and can lead to eventual death in patients with the disease. In 2006, a multidisciplinary group of experts and patient representatives developed an NMS screening questionnaire (NMSQuest) and a unified Non-Motor Symptoms Scale (NMSS) to address the need for simple identification and comprehensive assessment of NMS in patients with PD.

An international pilot study of 96 healthy controls and 123 patients with various stages of treated and untreated PD was conducted to demonstrate that the NMSQuest is a feasible, valid, and accepted tool.

The majority of patients and caregivers felt that the questionnaire was clear and relevant to their daily lives. Data from 242 PD patients with no dementia were analysed in a pilot study on the clinimetric validation of NMSS. Similar to the NMSQuest study, the NMSS study revealed a significant correlation between progression of PD and increasing NMS burden. These studies suggest that the NMSQuest accurately detects the NMS, and that the NMSS closely correlates with quality of life for PD patients.