Cognitive flexibility decline and right hemisphere's EEG alpha-band functional connectivity reorganization following...

The current study sought to investigate the relationship between cognitive flexibility and repetitive indirect brain impacts (RIBI) and to unravel the potential electrophysiological mechanism based on functional connectivity analysis. Forty-two male parachuters exposed to RIBI and 40 matched healthy controls (HC) were enrolled. Participants in the RIBI group had completed at least 40 actual jumps (46-106 times) and no less than 1000 simulated platform jumps (1000-4500 times). The RIBI group exhibited a significant increase in whole brain average time-frequency power within the alpha band, and a lower behavioral accuracy rate than the HC group. Spearman correlation revealed that the alpha band time-frequency power was negatively correlated with behavioral accuracy rates for both the repeat (r = -0.307, p = 0.048) and switch (r = -0.347, p = 0.024) conditions in the RIBI group. The RIBI group exhibited decreased alpha coherence (Coh) values predominantly noted between parietal and occipital regions in the right hemisphere, which indicate visual attention deficits in cognitive flexibility processing. Significantly increased alpha Coh values between frontal and parietal regions in the RIBI group, suggesting a compensatory brain response to cognitive flexibility impairment. Overall, this study provides robust evidence that the cumulative effects of RIBI can lead to a decline in cognitive flexibility. Additionally, enhanced frontoparietal and reduced parieto-occipital alpha functional connectivity in the right hemisphere reflects a unique adaptive reorganization of brain activity patterns following RIBI-induced cognitive flexibility impairment.