Sex difference in language cognition in the elderly group: a near-infrared spectroscopy study

Significance: There are sex differences in the incidence and prevalence of cognitive disorders, such as Alzheimer’s disease. Whether this difference is already present in the preclinical stage of the disease is unclear. Aim: We aim to explore whether there are sex differences in brain functional activities of specific cognitive tasks in the elderly and identify sex-related biomarkers of specific cognitive functions, which may provide important references for the mechanism disclosure and clinical early screening and diagnosis of cognitive disorders. Approach: We measured global cerebral hemoglobin concentrations and connectivity in elderly male (n ¼ 45) and female (n ¼ 44) groups during the letter and category verbal fluency tasks. The sex differences in activation and connectivity and their relationship with task performance were explored. Results: We found that there is a significant sex difference in connectivity, especially connectivity between the left inferior parietal and right prefrontal and left and right occipital in letter tasks, including the connectivity in parietal, left inferior parietal, and left occipital in category tasks. These connectivities were also significantly negatively correlated with the task performance of male groups. Conclusions: Our results indicated the connectivity between the left inferior parietal and right prefrontal, left and right occipital in letter tasks; the internal connectivity in the parietal; and the connectivity between parietal and the left inferior parietal and right occipital in category tasks may be crucial for verbal assessment of aging males. It is expected that the results will assist in cognitive assessment in the elderly group.