Regional homogeneity changes in early and advanced Parkinson’s disease: a resting state functional magnetic resonance imaging study

Objective: Previous work has shown regional homogeneity (ReHo) differences in Parkinson’s disease (PD) patients. So looking in more detail at differences between early and late stages is valuable. The aim of our study was to investigate brain activity of early and advanced PD in the resting state by using a ReHo approach. Methods: Functional magnetic resonance images were acquired in 35 patients with PD at in early stage and advanced stage, as well as in 17 ageand sex-matched normal controls (NC). Results: In PD patients compared with NC, we observed decreased ReHo in motor cortex and increased ReHo in the right cuneus and frontal eye field. In early stage of PD, decreased ReHo was located in bilateral posterior insular cortex, dorsolateral prefrontal cortex, angular gyrus, supramarginal gyrus, left precuneus, right superior temporal gyrus, and right cerebellar posterior lobe, in addition to motor cortex; and increased ReHo in the left cerebellar anterior lobe. During disease evolution, decreased ReHo was found in more brain areas, including right cerebellar posterior lobe, bilateral orbitofrontal cortex, gyrus rectus and left middle and inferior temporal gyrus; and increased ReHo in bilateral middle occipital gyrus, insular cortex, cingulate gyrus, superior temporal gyrus, and right middle temporal gyrus and thalamus. Whereas no changes were observed in bilateral motor cortex. Conclusion: Our results indicate that neuronal activity decrease in motor cortex with no marked variation during disease progression in a resting state, and decreased cognitive function may be associated with worsening motor symptoms in PD.