Sex-related differences in human cerebral hemodynamics

Area of Science:

• Neuroscience
• Cerebrovascular Physiology
• Sex Differences in Brain Function

Background:

• Cerebral hemodynamics, measured by mean flow velocity (MV), can vary between individuals.
• Understanding sex-related differences in brain blood flow is crucial for interpreting neurological health and disease.
• Transcranial Doppler (TCD) is a non-invasive tool for assessing cerebral blood flow.

Purpose of the Study:

• To investigate potential sex-related differences in inter-hemispheric cerebral hemodynamics at rest.
• To utilize transcranial Doppler (TCD) to measure mean flow velocity (MV) in healthy subjects.
• To explore correlations between age, sex, and cerebral blood flow velocity.

Main Methods:

• Mean flow velocity (MV) was recorded using TCD in 96 healthy, right-handed volunteers (48 males, 48 females).
• Participants were grouped by sex, with similar mean age and age-group distribution between males and females.
• Multiple regression models were employed to analyze the relationship between age, sex, and MV.

Main Results:

• A statistically significant sex-related difference in MV was observed in the left middle cerebral artery (MCA).
• Females showed a higher MV in the left MCA (58.5+/-10.4 cm/s) compared to males (53.5+/-8.2 cm/s) (P=0.005).
• Age correlated significantly with MV bilaterally, while sex was specifically associated with MV in the left MCA.

Conclusions:

• A sex-dependent hemispheric difference in left MCA MV at rest was identified, with higher flow in females.
• This finding was particularly noted in the younger population subgroup.
• The results align with anatomical observations suggesting proportionally larger Broca's area in females, potentially influencing cerebral hemodynamics.