Examining the time course of genital and subjective sexual responses in women and men with concurrent plethysmography and thermography

- MLM and cross-correlations revealed the strength and direction of sexual concordance varied throughout a 10-min sexual stimulus.
- No gender difference in sexual concordance, when assessed with thermography. Substantial variability in concordance observed across measures.
- Time course of sexual response was most similar between genital temperature and self-report, compared to VPP/PPG.
- Women's early changes in VPA predicted overall changes in genital temperature.
- Integrating findings across measures and statistical methodologies is warranted to enhance understanding of the complex sexual response process.

Sexual response is a dynamic process, though there is limited knowledge of the time course and relationships among its psychological and physiological components. To address this gap, we concurrently assessed self-reported sexual arousal, genital temperature (with thermography), and genital vasocongestion (with vaginal photoplethysmography [VPP] or penile plethysmography [PPG]) during sexual and nonsexual films in 28 androphilic women (attracted to men) and 27 gynephilic men (attracted to women). Men and women had similarly strong agreement between subjective and genital responses (sexual concordance) with thermography, but this agreement was stronger in men than women with PPG/VPP. The time course of changes in self-reported arousal was most similar to changes in genital temperature (i.e., time to onset and peak response). Time-lagged correlations and multilevel modeling revealed changes in the strength of relationships between aspects of sexual response over time. Results highlight the dynamic nature of sexual response and drawbacks of relying on zero-order correlations to characterize sexual concordance.