Abstract
The success of sildenafil in treating male erectile dysfunction has brought increasing attention from researchers, drug companies, and funding sponsors to develop an effective pharmacological treatment for female sexual dysfunction. Demonstrating treatment efficacy necessitates a valid and reliable index of female sexual response. The first observable sign of sexual arousal in women is vaginal lubrication and a simultaneous increase in vaginal vasocongestion. The three primary psychophysiological assessment devices that rely on indirect measures of vasocongestion are the vaginal photoplethysmograph, devices that indirectly measure heat dissipation, and pulsed-wave Doppler ultrasonography. The most widely used and studied of these is the vaginal photoplethysmograph, which detects differences in transparency of engorged and unengorged vaginal tissue using a light reflectance method. Research has demonstrated the construct validity of this device and its response specificity to sexual stimuli. However, a recurrent issue with the use of this device is the lack of correspondence between genital measures of vasocongestion and subjective reports of “feeling sexually aroused.” This contrasts with findings in men, which generally show high concordance between subjective and physiological measures. Evidence suggests that external stimulus information (e.g., relationship issues, sexual scenarios) may play a more important role in assessing feelings of sexual arousal than do internal physiological cues. Consistent with this is the fact that men are more accurate than women at detecting physiological changes in general (e.g., heart rate, blood pressure), but only when situational cues are absent. Clearly, this raises important conceptual issues in the definition of female sexual arousal.
