Abstract
BACKGROUND: Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor and non-motor symptoms that substantially affect quality of life (QoL). While dopaminergic dysfunction is central to PD pathology, the cross-sectional relationship between striatal dopaminergic activity and clinical outcomes remains incompletely understood. This study investigated associations between dopaminergic activity, measured via DATSCAN imaging, and clinical outcomes including cognitive performance, mobility, and QoL. METHODS: In this cross-sectional observational study, PD patients (n = 146; age 37.9-85.6 years) and healthy controls (n = 37; age 32.2-86.7 years) were evaluated. Cognitive and communication-related QoL were assessed using Neuro-QoL, motor and non-motor symptoms were quantified with MDS-UPDRS, and cognitive performance was measured using COGSTATE and derived indices (COGDECLN, COGCHG). DATSCAN imaging quantified striatal dopaminergic activity in the caudate and putamen. Correlations between DATSCAN metrics and clinical outcomes were analyzed, accounting for multiple comparisons. RESULTS: DATSCAN metrics showed no significant associations with cognitive performance or QoL, and only modest correlations with mobility measures. Sensitivity analyses confirmed robustness of these findings. The limited predictive value of DATSCAN underscores the complexity of PD, including contributions of non-dopaminergic mechanisms. CONCLUSIONS: Although DATSCAN is valuable for confirming PD diagnosis, its ability to predict clinical outcomes such as cognition, QoL, or motor complications is limited. These results highlight the multifactorial nature of PD and the need to integrate dopaminergic imaging with comprehensive clinical assessments for personalized patient care.