Sex differences in EEG correlates of a self-reported measure of hemisphere preference

The present study explored sex differences in hemisphere preference (HP) assessed by the Preference Test (PT) and its EEG correlates. PT is a paper-and-pencil test designed to measure the extent of individuals relaying on right-hemisphere or left-hemisphere cognition. "Study 1" verified sex differences in HP only among subjects with statistical significant differences between mean and/or median of right- respect to left-HP abilities scores. No sex differences in the Frequency of right- and left-HP among the 16 to 17% of a cohort of 1,057 young subjects (473 men and 584 women) with a significant HP were registered. Minimal sex-differences were observed in relation to the magnitude of PT score. "Study 2" verified on 34 healthy adults (22 women and 12 men) the sex differences in correlation between PT-defined HP and a more direct index of hemisphere activation such as the alpha power asymmetry derived from resting EEG (vertex reference). In both sexes, PT scores were found to be related with frontal (0.54 women, 0.69 men), but not parietal, alpha power asymmetries. Higher positive correlation of PT score with frontal alpha ratios was reported in both sexes when the median difference of right- respect to left-HP abilities scores in PT score calculation was used. Overall, this study confirmed and extended the evidence on the association between PT-defined HP and frontal, but not parietal, alpha power asymmetries. No significant sex differences were registered in this pattern.