Sex differences in parietal alpha power during sustained attention are related to conflict monitoring performance in mild cognitive impairment

BackgroundSex differences in cognition among individuals with dementias and prodromal stages such as amnestic mild cognitive impairment (aMCI) manifest in variations in severity and prevalence, but underlying brain activity patterns remain unclear. This study is a secondary endpoint study of the Cogmax project.ObjectiveWe examined sex differences in parietal alpha power during an attention task (Simple Vigilance Task, SVT) and its association with conflict monitoring (Stroop Color-Word Test Part 3, T score) in individuals with aMCI.MethodsThe SVT served as the EEG recording condition because of its low cognitive demands and visually driven structure, while the Stroop task provided an independent neuropsychological measure of conflict monitoring. Seventy-seven participants (23 females; 54 males) were included. We analyzed average power spectral density (PSD) across occipital and parietal electrodes (O1-Pz-O2-P7-P8) using multitaper Fourier transform. Normalized alpha power was calculated as integrated 7-11 Hz relative to total 0.1-40 Hz PSD.ResultsAll participants showed high accuracy on the SVT, indicating stable attentional engagement. Covariate-adjusted permutation tests, robust to unbalanced sample sizes, showed that females exhibited higher parietal alpha power and higher Stroop Part 3 T-scores than males. However, when Stroop performance was included as a covariate, the sex difference in alpha power became nonsignificant. A positive correlation between Stroop 3 scores and parietal alpha power was observed in females but not in males, suggesting a sex-specific relationship.ConclusionsParietal alpha activity may be associated with conflict monitoring performance in aMCI, particularly among females, providing evidence for sex-related neural differences in aMCI.