A comparison of volumetric and circumferential measures of penile erection.

Objective measurements of sexual arousal in men most commonly involve monitoring changes in penile size. Although changes in circumference are most often used, volumetric changes have been reported to be more sensitive and thus more effective. Six men volunteered to observe an erotic videotape while circumferential and volumetric changes of their penises were recorded. The two measures were significantly correlated (r = .68) but the volumetric device was more difficult to use, displayed considerably more artifacts, and was not more sensitive than a mercury-in-rubber strain gauge.