# Exploring the Potential of Voxel-Mirrored Homotopic Connectivity (VMHC) and Regional Homogeneity (ReHo) in Understanding Cognitive Changes After Heart Transplantation

## TL;DR

This study shows that brain connectivity measures can reveal cognitive changes in heart transplant patients compared to healthy individuals.

## Contribution

The study identifies specific brain regions with altered connectivity linked to cognitive decline after heart transplantation.

## Key findings

- Heart transplant patients had lower MMSE and MoCA scores compared to healthy controls.
- Altered ReHo and VMHC were observed in brain regions like the frontal and temporal lobes and cerebellum.
- Changes in ReHo and VMHC in certain brain regions correlated with cognitive function scores.

## Abstract

Objective: This study aimed to investigate the application value of voxel-mirrored homotopic connectivity (VMHC) and regional homogeneity (ReHo) in evaluating cognitive impairment after heart transplantation. Methods: A total of 68 heart transplant patients and 56 healthy controls were included. ReHo and VMHC were calculated using DPARSF software. A two-sample t-test was applied to compare the differences in ReHo and VMHC between the two groups, and a Pearson correlation analysis was performed by extracting the VMHC and ReHo values of different brain regions and correlating them with cognitive scale scores of the patient groups. Results: Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scores were lower in the heart transplant group than in the control group (MMSE: t = 4.028, p < 0.001; MoCA: t = 4.914, p < 0.001). Compared with the control group, the ReHo values of Frontal_Sup_R (t = −4.422, p < 0.001), Thalamus_L (t = −3.911, p < 0.001), and Calcarine_L (t = −3.640, p < 0.001) were lower in the heart transplantation group, while the ReHo of Temporal_Sup_L was higher (t = 4.609, p < 0.001). VMHC was elevated for bilateral Cerebellum_Crus1 (t = 3.803, p < 0.001) and decreased for bilateral calcarine (t = −3.424, p < 0.001). The ReHo of Frontal_Sup_R was positively correlated with MMSE (r = 0.345, p = 0.004) and MoCA (r = 0.376, p = 0.002). The ReHo of Temporal_Sup_L was also positively correlated with MMSE (r = 0.397, p < 0.001) and MoCA (r = 0.542, p < 0.001). The VMHC of bilateral calcarine showed a positive correlation with MMSE (r = 0.513, p < 0.001) and MoCA (r = 0.398, p < 0.001). Other differential brain regions showed no significant correlation with the MMSE and MoCA scale scores. Conclusions: Cognitive decline was observed in heart transplant patients. Heart transplant patients exhibited altered ReHo and VMHC in several brain regions compared with healthy controls. These changes may underlie impaired cognitive function in heart transplant patients. These findings may contribute to understanding the neural mechanisms of cognitive changes in heart transplant patients and could inform future research on potential intervention strategies.