Cardiovascular Reactivity to Speech Processing and Cold Pressor Stress: Evidence for Sex Differences in Dynamic Functional Cerebral Laterality

This experiment investigated sex differences in dynamic functional cerebral laterality effects on cardiovascular reactivity and dichotic listening in response to a stressor (a cold pressor). 120 right-handed undergraduate men (N = 60) and women (N = 60) underwent physiological measurements of systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) before and after exposure to the cold pressor and a phonemic dichotic listening task. Functional cerebral laterality was assessed through the administration of the phonemic dichotic listening task. Group differences in dynamic functional cerebral laterality were predicted.

Findings indicated a sex by focus interaction effect where men's, but not women's, systolic blood pressure increased significantly when focusing on sounds presented at the left ear during the dichotic listening task. Also, a compartmentalized, dynamic response in dichotic listening test performance was evidenced in both men and women (as both experienced increased accuracy at the right, but not left, ear), brought about as a function of the cold pressor. Men and women both evidenced increased cardiovascular reactivity, with men experiencing significantly more cardiovascular reactivity (SBP) than women in response to cold pressor pain. Women were also able to identify significantly more speech sounds presented to the left ear than men, and they were able to dynamically increase accuracy at the targeted ear identified within each focus group (left or right). Speech sounds processing (dichotic listening task) significantly decreased men's, but not women's, systolic blood pressure. These results contribute to the literature on sex differences in functional cerebral laterality.