Correlation of Plasma Neuropeptide Y with Specific Cognitive Domains in Patients with Parkinson's Disease Cognitive Impairment

BACKGROUND: We aimed to investigate the correlation of plasma neuropeptide Y (NPY) with specific cognitive domains in patients with Parkinson's disease (PD) cognitive impairment (CI). METHODS: The study included thirty-six PD patients with normal cognitive function (PD-NC), 57 PD patients with mild cognitive impairment (PD-MCI), 30 PD patients with dementia (PDD), and 46 healthy individuals. Every patient underwent thorough clinical evaluations and neuropsychological examinations. Plasma NPY expression was assessed using ELISA. The effects of plasma NYP levels on PD-CI events or PDD were analyzed using univariate and multivariate logistic models. Multiple linear regression analyses were constructed to assess the independent associations of plasma NYP levels with z scores in 5 cognitive domains. RESULTS: Plasma NYP levels were reduced in patients with PD compared with healthy controls (p < 0.001). Plasma NYP levels were the highest in PD-NC patients and decreased with increasing CI, with the PDD group having the lowest plasma NYP levels. Multivariate logistic regression adjusted for years of education and UPDRS-III subscores showed a significant correlation between NYP and CI (p = 0.005). Plasma NYP was significantly correlated with a linear model between each of the 5 cognitive domains, including attention, executive function, language, memory, and visuospatial function. CONCLUSIONS: Reduced plasma NPY levels are associated with CI in PD patients and are strongly correlated with 5 cognitive domains.