Abstract
BACKGROUND: Although the clitoris is more sensitive to stimulation and its innervation more conducive to sensory feedback than the vagina, the field of sexual psychophysiology, which uses psychophysiological methods including genital response measures to study sexual arousal, relies heavily on the measurement of vaginal, rather than clitoral, pulse amplitude. AIM: To develop and test a new clitoral photoplethysmograph for the measurement of clitoral pulse amplitude (CPA). METHODS: 2 versions of the new device, which differed in the orientation of the sensor and light source (parallel vs angled), were tested in 15 premenopausal, sexually functional women. Vaginal pulse amplitude (VPA) was assessed simultaneously. The women viewed a 3-minute erotic and an anxiety-inducing film segment with each clitoral sensor, interspersed with neutral video excerpts. In addition, they were asked to indicate their subjective level of sexual arousal during and after erotic video presentations. OUTCOMES: The main outcome measures are CPA, VPA, and subjective sexual arousal. RESULTS: The clitoral photoplethysmograph successfully detected CPA. The quality of the signals was best for the angled sensor. Main effects of the film and the interaction between the film and epoch were stronger for the clitoral than for the vaginal device. In addition, CPA followed more closely changes in intensity of sexual films than VPA. Within- and between-subject correlations between genital response and subjective sexual arousal were higher for the clitoral than for the vaginal device. CLINICAL TRANSLATION: Comparison of CPA with other genital blood flow measures in clinical samples is indicated and may contribute to improved physiological assessments of sexual response in women. STRENGTHS AND LIMITATIONS: Our sample was small and consisted of healthy volunteers. Future research could examine test-retest reliability, by including multiple recording sessions, and further explore the specificity of CPA by comparing sexual and non-sexual stimuli with positive valence. CONCLUSION: This study presents the first instrument to successfully measure CPA. Mechelmans DJ, Sachtler WL, von Wiegand TE, et al. The Successful Measurement of Clitoral Pulse Amplitude Using a New Clitoral Photoplethysmograph: A Pilot Study. J Sex Med 2020;17:1118-1125.