Gray Matter Volume Abnormalities in Stroke-free Atrial Fibrillation With and Without Mild Cognitive Impairment.

BACKGROUND

Individuals with atrial fibrillation (AF) are more likely to develop mild cognitive impairment (MCI), but the underlying mechanisms remain unclear. The study aimed to investigate cognitive-related gray matter (GM) volume alterations in stroke-free individuals with AF using voxel-based morphometry (VBM).

METHODS

3D-T1-weighted magnetic resonance imaging (MRI) scans were obtained from 40 stroke-free AF individuals with MCI (AF-MCI), 40 stroke-free AF individuals with normal cognition (AF-NC), and 40 healthy controls (HCs). GM atrophy was assessed using VBM.

RESULTS

The results revealed widespread GM atrophy in stroke-free individuals with AF, regardless of their cognitive status, with more pronounced GM loss in the AF-MCI group. Significant GM volume reductions were found in several brain regions, including the temporal lobe, parahippocampal gyrus (PHG), cerebellum, and frontal lobe, in the AF-MCI group. Notable reductions in the left PHG and right inferior parietal lobule were observed in the AF-MCI group compared with the AF-NC group. Moreover, decreased GM volume in the left PHG, right superior temporal pole, and right orbital part of the inferior frontal gyrus was positively correlated with cognitive performance.

CONCLUSIONS

Among AF individuals free of stroke, degeneration of the PHG correlates with a greater probability of developing MCI. Structural alterations in the brain may be related to the transition from normal cognition to MCI in stroke-free individuals with AF. This study highlights the potential for targeted interventions aimed at slowing cognitive decline in stroke-free AF individuals by focusing on these structural alterations.