Subregional alterations in corpus callosum is associated with different symptoms in early-stage parkinson's disease

Corpus callosum (CC) damage is the most consistent and typical change in early Parkinson's disease (PD), and is associated with various PD symptoms. However, the precise relationship between CC subregions and specific PD symptoms have not been identified comprehensively. In this study, we investigated the association between specific CC subregion alterations and PD symptoms using diffusion-weighted imaging.

70 PD patients in early-stage from the Parkinson's Progression Markers Initiative cohort were included. Fixel-based analysis (FBA) was used to calculate mean values of fiber density (FD), fiber cross-section (FC), and combined measure of FD and FC (FDC) for 7 CC subregions. Regression analyses between FBA metrics and PD symptom scores were performed to evaluate associations between CC subregion metrics and clinical symptom scores. Diffusion tensor imaging (DTI) metrics were also analyzed.

The score of akinetic rigid symptoms was negatively associated with FDC value of CC rostral body. The score of Activities of Daily Living was positively associated with FD value of CC anterior midbody. The score of gastrointestinal dysfunction was negatively associated with FDC value of CC rostrum. The severity of thermoregulatory dysfunction and cognitive decline was accompanied by an improvement in FBA metrics for several CC subregions. No significant associations were found using DTI metrics.

In early-stage of PD, motor, autonomic, and cognitive functions are associated with specific subregions of CC, and compensatory changes in CC may exist to maintain normal autonomic and cognitive functions.