Altered functional connectivity in language and non-language brain networks in patients diagnosed with acute post-stroke aphasia.

Objective: A resting-state functional magnetic resonance imaging (rs-fMRI) approach was used to explore functional connectivity (FC) in language and non-language brain networks in acute post-stroke aphasia (PSA) patients, with a specific focus on the relationship between these fMRI results and patient clinical presentation.

Methods: In total, 20 acute PSA patients and 30 age-, sex-, and education level-matched healthy control (HC) participants were recruited and subjected to rs-fMRI imaging. In addition, western aphasia battery analyses（WAB） were used to compute aphasia quotient (AQ) values for PSA patients. Granger causality was employed to examine connections among cognition-associated resting-state brain networks, and the right middle frontal gyrus (RMFG),the mirror brain regions of Broca's area and the Wernicke's area, the right superior temporal gyrus were selected as regions of interest (ROIs). The REST plus software was then used to perform FC analyses of these regions to analyze changes in FC related to PSA pathogenesis.

Results: Relative to HC individuals, PSA patients exhibited significantly higher levels of intra-network FC between the right middle frontal gyrus (RMFG) and the left middle occipital gyrus (LMOG), with such FC being positively correlated with the AQ scores (P = 0.018). Moreover, reduced FC was detected between the Broca's area homolog and the left middle frontal gyrus (LMFG), while FC was enhanced between the Wernicke's area homolog and cerebellar vermis, and this FC was similarly positively correlated with patient AQ scores (P = 0.0297).

Conclusion: These results suggest that FC between the bilateral hemispheres of the brain is significantly disrupted in acute PSA patients, interfering with the normal non-specific language network. Aphasia severity was further found to correlate with FC among many of the analyzed regions of the brain.