Brain activity alterations in patients with Parkinson’s disease with cognitive impairment based on resting-state functional MRI

ABSTRACT Objective This study aimed to investigate the differences in regional homogeneity (ReHo) values in patients with Parkinson’s disease (PD) with cognitive impairment (PD-CI) and thus explore the neuropathological mechanism of PD-CI. Methods Resting-state functional magnetic resonance imaging scans were obtained from 36 patients with PD and 20 healthy controls (HCs) in this study. The PD group comprised 20 patients with PD-CI and 16 patients with PD with normal cognitive function (PD-NC). The data were analyzed using ReHo analysis to observe the changes in brain activity in patients with PD-CI and PD-NC. Statistical comparison was performed using covariance analysis and post hoc t tests. Results The patients in the PD-CI group were older than those in the PD-NC and HC groups. Compared with the HC group, the PD-CI group showed that the ReHo value decreased in the right supplementary motor area, left lingual gyrus, left thalamus, and left precuneus, but increased in the left fusiform gyrus. Compared with the HC group, the PD-NC group showed that the ReHo value decreased in the right cerebellum_6, but increased in the left inferior temporal gyrus, left orbital inferior frontal gyrus, and left precentral gyrus. Compared with the PD-NC group, the PD-CI group showed that the ReHo value decreased in the right precuneus, left triangular inferior frontal gyrus, left middle frontal gyrus, right opercular inferior frontal gyrus, left orbital inferior frontal gyrus, left supramarginal gyrus, left angular gyrus, left inferior temporal gyrus, and right cerebelum_7b, but increased in the left precentral gyrus and left fusiform gyrus. Conclusions Age was a risk factor for cognitive decline in patients with PD. The ReHo value in the default mode network (DMN) was closely related to PD cognitive function, and the DMN was affected before CI and continuously deteriorated with disease progression. The disorder of visual conduction pathway was involved in CI in patients with PD, but these patients could recruit cognitive resources by improving visual–spatial ability. The cognitive function in such patients was related to the dopaminergic, cholinergic, and noradrenergic systems. The information transmission efficiency of the cerebellum–thalamus–cortex loop was reduced and involved in the cognitive decline process in patients with PD.