Resting-state fMRI study on male patients with Parkinson's disease and with sexual dysfunction

Sexual dysfunction (SD) is a common non-motor symptom in Parkinson's disease (PD) that substantially reduces patients' quality of life. However, the underlying neural mechanisms of SD in PD remain poorly understood. This study aimed to investigate the role of functional abnormalities in brain regions with dopaminergic innervation in male PD patients with SD, using resting-state functional magnetic resonance imaging (rs-fMRI). A total of 34 male PD patients were enrolled. The bilateral caudate, putamen, nucleus accumbens, and hypothalamus were selected as regions of interest (ROIs), and seed-based functional connectivity (FC) analysis was performed to compare differences in brain connectivity between PD patients with sexual dysfunction (PD-SD) and those without sexual dysfunction (PD-nSD). Compared to PD-nSD patients, those with SD exhibited significantly reduced FC between the left putamen and the right inferior parietal lobule, between the right lateral hypothalamus (LH) and the right middle frontal gyrus, and between the right medial hypothalamus (MH) and the right postcentral gyrus. These altered FC patterns effectively distinguished PD-SD from PD-nSD patients. Moreover, FC abnormalities involving the LH were significantly correlated with SD severity, as measured by the International Index of Erectile Function (IIEF), in PD-SD patients. In summary, our findings suggest that dysfunction in dopaminergically innervated brain regions may contribute to the pathophysiology of SD in male PD patients. These results offer novel insights into the neural substrates of SD in PD.