Differentiating patterns of neuro-circuitry abnormalities in tremor dominant parkinson's disease and multiple system...

This study aimed to elucidate distinctive patterns of brain functional activity in tremor-dominant Multiple System Atrophy (MSA) and Parkinson's Disease (PD) patients and develop a diagnostic model distinguishing between the two conditions based on these changes. Resting-state fMRI data from 45 MSA patients, 55 PD patients, and 48 healthy controls were analyzed using Percent Amplitude of Fluctuation (PerAF), Functional (FC) and Effective Connectivity (EC) analyses. The Support Vector Machine (SVM) was used to create the diagnostic model from the identified functional alterations. Partial correlation analyses explored the relationship between functional abnormalities and tremors. Both MSA and PD patients with tremors exhibited similar activity changes in bilateral Orbital part of the superior frontal gyrus (ORBsup), Cerebellum VIII (CRBL8), left Cerebellum IV-V (CRBL45.L), right rectus (REC), and FC based on the seeds of PUT.L, CRBL8.R, and REC.R. These changes were more pronounced in MSA patients. However, MSA patients exhibited heightened putamen activity and enhanced EC from caudate (CAU) to putamen, whereas these activity and connectivity were decreased in PD patients. The SVM model achieved strong performance, with the putamen exerting the most significant influence on classification. In summary, dysfunction within the cerebello-cortical and basal ganglia network circuits is implicated in the tremors of both MSA and PD patients. The alteration in cerebellar-cortical regions were similar, with MSA displaying more pronounced changes, contrasting changes were observed in the basal ganglia region. The putamen may serve as crucial neurobiological indicators for the precise differentiation of MSA and PD patients.