Predictors of dopamine dysregulation syndrome in patients with early Parkinson's disease.

BACKGROUND: Dopamine dysregulation syndrome (DDS) is a complication of Parkinson's disease (PD) that seriously affects the quality of life of PD patients. Currently, the risk factors for DDS are poorly known, and it is critical to identify them in the early stages of PD. OBJECTIVE: To explore the incidence of and risk factors for DDS in patients with early PD. METHODS: A retrospective cohort study was conducted on the general data, clinical features, and imaging data of patients with early PD in the PPMI database. Multivariate Cox regression analysis was performed to analyze the risk factors for the development of DDS in patients with early PD, and Kaplan‒Meier curves examined the frequency and predictors of incident DDS symptoms. RESULTS: At baseline, 2.2% (n = 6) of patients with early PD developed DDS, and the cumulative incidence rates of DDS during the 5-year follow-up period were 2.8%, 6.4%, 10.8%, 15.5%, and 18.7%, respectively. In the multivariate Cox regression model controlling for age, sex, and drug use, hypersexuality (HR = 3.088; 95% CI: 1.416~6.732; P = 0.005), compulsive eating (HR = 3.299; 95% CI: 1.665~6.534; P = 0.001), compulsive shopping (HR = 3.899; 95% CI: 1.769~8.593; P = 0.001), anxiety (HR = 4.018; 95% CI: 2.136~7.599; P < 0.01), and lower Hoehn-Yahr (H-Y) stage (HR = 0.278; 95% CI: 0.152~0.509; P < 0.01) were independent risk factors for DDS in patients with early PD. PD patients with DDS had lower DAT uptake values than those patients without DDS. CONCLUSION: Early PD patients with hypersexuality, compulsive eating, compulsive shopping, anxiety, and lower H-Y stage were at increased risk for DDS. The occurrence of DDS may be related to the decrease in the average DAT uptake of the caudate and putamen.

Associations of blood UCH-L1 and NfL levels with cognitive dysfunction in Parkinson's disease patients.

OBJECTIVE: Ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) and Neurofilament light chain (NfL) are associated with Lewy body formation, Lewy bodies are the main pathological feature of Parkinson's disease (PD). The relationship between UCH-L1 and PD cognition remains unclear, and NfL is an important marker of cognitive impairment. The aim of this study is to investigate the relationship among serum UCH-L1 levels, plasma NfL levels and cognitive dysfunction in PD patients. RESULTS: There were significant differences in UCH-L1 and NfL levels among PD patients with normal cognitive function (PD-CN), PD patients with mild cognitive impairment (PD-MCI), and PD-dementia patients (PDD) (P < 0.001; P < 0.001). The PDD group had lower levels of UCH-L1 (Z = 6.721, P < 0.001; Z = 7.577, P < 0.001) and higher levels of NfL (Z = -3.626, P = 0.001; Z = -2.616P = 0.027) than the PD-NC and PD-MCI groups. Serum UCH-L1 levels were positively correlated with MMSE scores, MoCA scores, and its subitems in PD patients (P < 0.001), and plasma NfL levels were negatively correlated with MMSE scores, MoCA scores, and its items (P < 0.01) (except for "abstract"). CONCLUSION: Decreased UCH-L1 levels and elevated NfL levels in the blood are associated with cognitive dysfunction in PD; thus, these proteins are potential biomarkers for the diagnosis of cognitive dysfunction in PD patients.