Nonmotor symptoms in early- and advanced-stage Parkinson's disease patients on dopaminergic therapy: how do they correlate with quality of life?

To determine the impact of nonmotor symptoms (NMS) on health-related quality of life (HRQoL) we examined 100 Parkinson's disease (PD) patients on dopaminergic medications. An "early-stage" (ES) and an "advanced-stage" (AS) groups were formed. HRQoL was established by the questionnaire PDQ-8, number of NMS by NMSQuest, and severity and frequency of NMS by the assessment scale NMSS. The total NMS averaged 11.3 (ES = 9.6, AS = 12.8). The NMSS domain correlation profiles for ES and AS did not fundamentally differ; however, the domains attention/memory and mood/apathy correlated moderately to strongly with HRQoL in ES, while the sleep/fatigue domain correlated moderately with HRQoL in AS. Weakly correlating domains were sleep/fatigue in ES and cardiovascular, attention/memory, and mood/apathy domains in AS. In view of these findings we strongly recommend systematic, active screening and therapy for neuropsychiatric disorders (mood, cognitive and sleep disorders, and fatigue) at the initial diagnosis and throughout the entire course of PD.