The Vaginal Photoplethysmograph

The vaginal photoplethysmograph is a small, tampon-shaped device which is self-inserted into the vagina and measures Vaginal Blood Volume, Vaginal Pulse Amplitude, and heart rate in response to an erotic stimulus. The vaginal photoplethysmograph is completely safe and is sterilized in Cydex-activated glutaraldehyde. This sterilizing procedure is commonly used with hospital instruments and is known to prevent both viral and bacterial transmission of infection. Participants insert the device in the privacy of a locked room.

The vaginal photoplethysmograph yields two signals of interest to sexual psychophysiology researchers. One is Vaginal Blood Volume (VBV) and represents general pooling of blood into the genital region.  The second is Vaginal Pulse Amplitude (VPA) and is thought to represent moment-to-moment changes in vaginal vasocongestion with each heartbeat.  Given that there is no "zero point" with the vaginal photoplethysmograph, women are shown a neutral and an erotic stimulus and the levels of arousal between these two conditions are compared.  Subsequently, this degree of "change" is compared between different women.  The genital response occurs within seconds of the presentation of an erotic stimulus in sexually healthy women, regardless of age or menopausal status.