Sex-related differences in human cerebral hemodynamics

Objectives - To identify possible inter-hemispheric sex-related cerebral hemodynamic differences at rest, in healthy subjects by transcranial Doppler (TCD). Subjects and methods - Mean flow velocity (MV) was recorded by TCD in 96 (48 males, 48 females) right-handed volunteers. Mean age was similar in males and females, distribution of age-groups by sex was similar, too. Results - Examining by sex MV values in each basal artery, left middle cerebral artery (MCA) showed a statistically significant difference (53.5+/-8.2 cm.s(-1) in males versus 58.5+/-10.4 cm.s(-1) in females, P=0.005, one-way ANOVA). Multiple regression models show a significant correlation between age and MV on each side, while sex correlates with MV on the left side. Conclusion - A sex-dependent hemispheric difference in MV in the left MCA at rest (females>males) in the younger population subgroup was identified. These data support recent observations on anatomical differences between sexes, referring a proportionally larger Broca area in females compared to males.