Devices for Measuring Vaginal Sexual Response

Invented by John D. Perry, PhD

	The Uterine Myograph (1980)   Three silver electrodes are embedded in the rim of a "Cervical Cap", which was molded in dental acrylic from a Prentif (UK) cervical cap contraceptive device.  Research using this device was published in the Perry & Whipple article in  Journal of Sex Research (Feb. 1981)
The "Napkin Ring Myograph" (1984) was molded from a Danish import.  It features three silver electrodes which make contact with the vaginal wall at the level of the pubococcygeus muscle. (Only one electrode is pictured clearly here.)  The hollow ring allows stimulation of the Gräfenberg Spot on the anterior vaginal wall even while the electrode is in place in the vaginal entrance.  Research using this device and the Cervical Cap Myograph is posted on this website.
	The Cervical Photoplethysmograph (CPPG) (1980) contains an infrared LED and IR detector mounted in the rim.  It was used to obtain pressure pulse measurements in the cervix during various forms of sexual stimulation.  The device is an adaptation of the traditional "Geer Gauge" used to measure vaginal-wall blood levels.