The past decade has seen a resurgence of research into women's sexual health. The International Society for Women's Sexual Health is a multidisciplinary scientific society committed to enhancing knowledge about women's sexual function, experiences, and sexual health in research, clinical practice, and education. The conference includes both a scientific program of research and overview papers and instructional courses. The theme of this spring conference reflected on women's sexuality in the context of the senses. Presenters examined the evidence for how sensual stimuli affected women and some of the underlying mechanisms by which women process such sensations. Of the many interesting presentations, I have chosen to summarize some of the presentations with future clinical and research potential. The report also includes a synopsis of the plight of medical education in the field of sexual health. I would like to thank the presenters for their input and contributions to this report.
Yitzchak Binik, Professor of Psychology at McGill University, Montreal, Canada, spoke on tactile sensitivity and sexual pain.[1] He noted that despite the fact that psychophysics has provided reliable measures of touch and pain thresholds all over the body, the female genitalia have not been systematically studied until recently. Binik and colleagues[2] have studied the condition of vulvar vestibulitis syndrome (VVS [vestibulodynia]) and the hypothesis that a local sensory disruption in the vulvar vestibule is responsible. Women with VVS have lower pain and touch thresholds in the vulvar vestibule as compared with control subjects. Affected women also have lowered tactile and pain thresholds elsewhere in the body.[2] The lowered thresholds outside the genitalia suggest a more generalized pain processing problem as the underlying mechanism for VVS rather than the previously hypothesized localized disruption.[3] Clinical implications include caution about the use of the cotton swab test as a diagnostic method, because it is impossible for a clinician to control the pressure exerted. A new instrument called a vulvalgesiometer has been proposed to help correct this problem.[4] A second clinical implication is that local vulvar creams may not be appropriate therapies, because they do not affect the proposed central pain mechanism. Finally, additional data presented suggest that the often-used sex therapy strategy of increasing sexual arousal to reduce pain may not be appropriate since the induction of sexual arousal in women suffering from VVS and in matched controls actually reduced both pain and touch thresholds in the vulvar vestibule (unpublished data). Thus women with VVS experience pain at a lower threshold of touch when sexually aroused.
The neuronal mechanisms and structures invoked by visual stimuli were presented by Kenneth Maravilla, Professor of Radiology and Neurological Surgery and Director of MRI Research Laboratory at the University of Washington, Seattle. He presented research findings based on neuroimaging of women's sexual function.[5] Functional brain imaging (fMRI) was used as a means to observe anatomic sites of neuronal activation in response to arousal evoked by a visual sexual stimulus. Maravilla reported that their fMRI studies of healthy, premenopausal women without sexual difficulties revealed multiple areas of increased activation associated with sexual arousal (hypothalamus, occipital areas, amygdala, frontal lobes). These results are in agreement with previous studies, such as those of Park and colleagues[6] and Karama and colleagues.[7] Maravilla also reported areas of decreased activation during sexual arousal, in both temporal lobes, predominantly in the superior and middle temporal gyri on the right. He hypothesized that this decreased activation during arousal in women without sexual problems represents sites of normally active inhibition that are deactivated during sexual arousal. These anatomic areas have also been associated in other studies with areas of embarrassment or moral judgment.
Maravilla then demonstrated how the technology of fMRI can be applied to assist in unraveling the mechanisms involved in female sexual dysfunction. In a small pilot study of 4 women with female sexual arousal disorder (FSAD), Maravilla reported there was less brain activation seen in this group, including very little activation in the amgydala (Figure 1). These women also showed increased activation in the temporal areas, in contrast to women without sexual difficulties, who showed deactivation in similar areas. This may suggest an increased level of inhibition with an arousal stimulus in this small group of women with FSAD. This technology may be useful in evaluating the effects of treatments such as new pharmacologic agents.
Bilateral temporal lobe activation during arousal in subject with female sexual arousal disorder.
Laan[8] reported new findings on gender differences in processing of visual sexual information. Laan is Associate Professor in the Department of Sexology and OBGYN of the Academical Medical Center at the University of Amsterdam, the Netherlands. Previous research has highlighted the huge variations in awareness of bodily sensations among women. Genital arousal, as measured by vaginal photoplethysmography, was found to be largely unrelated to women's subjective sexual experience as self-reported.[9] It has been argued that women have a greater need for cognitive inhibitory mechanisms because of their greater investment in reproduction and parenting. Laan and colleagues set out to contrast male and female abilities to inhibit sexual arousal. Sexual arousal was provoked with visual stimuli because these are the most effective provocative stimuli for arousal in both men and women. Oral sex and intercourse were found to be the most arousing images. The experimental design was carried out in 2 sessions: an fMRI setting and a psychophysiologic laboratory. Both genital and subjective arousal were recorded in the latter setting. The design utilized both sexual arousal and inhibition conditions. Laan[9] reported that fMRI identified gender differences in brain sites activated during inhibition conditions that indicated men are better at conscious (voluntary) suppression of sexual activation whereas women have more involuntary suppression of arousal. Laan also reported a discord in both sexes between the fMRI results and results found from measures of genital arousal. Although the fMRI indicated some inhibition of arousal, genital arousal was not inhibited. This suggests that female genital arousal has a larger autonomic component than subjective response, is involuntary, and not under conscious control. Laan reported no age difference in female genital arousal and no difference between premenopausal and postmenopausal subjects. She speculated that men may be better able to carry out genital inhibition of arousal because their anatomy provides direct biofeedback, enabling men to learn control of arousal.
A "State-of- the-Art Lecture" on the role of smell in female sexual function was presented by McClintock,[10] who is a psychologist and a biologist. McClintock is the David Lee Shillinglaw Distinguished Service Professor in Psychology, Director of the Institute for Mind and Biology, and Co-Director of the Center for Interdisciplinary Health Disparities Research at the University of Chicago, Illinois. Her early studies involved ovarian pheromones, social chemical signals that trigger species-specific endocrine, physiologic, or behavioral responses. She demonstrated that ovarian pheromones mediate menstrual synchrony in women.[11,12] McClintock outlined that there are 3 types of olfactory functions served by social chemical signals. At high concentrations, compounds are detectable consciously and perceived as body scents and odors. We have preferences and can discriminate, habituate, and generalize about them. At minute concentrations, some social chemical signals function as pheromones, which are not recognized consciously but do have potential to change behavior of another individual. McClintock used the Sanskrit word "vasana," which refers to subconscious inclinations, to describe chemosignals that function at concentrations intermediate between these types; although not consciously recognized, these signals have marked effects on reproductive-related behaviors. She presented a series of elegant experiments carried out by her research team to illustrate the role of these non-consciously detected chemosignals.
Animal research has demonstrated that species prefer and can detect a mate that differs genetically. McClintock's work has concentrated on the major histocompatibility complex (MHC) alleles, which are genetically distinct for each person. Other researchers had demonstrated that married couples in a religious community, an inbred population living in traditional and isolated communities in the United States, were less likely to share MHC alleles than randomly expected. McClintock, with her colleagues, set out to determine whether these women could detect differences in MHC alleles by odor alone.[13] When given choices from an ethnically diverse population with whom they shared few alleles, would they prefer complete differences (inbreeding avoidance) or would they avoid complete differences and prefer some degree of similarity (outbreeding avoidance)? The investigators studied unmarried women's responses to body scents collected from men to whom their genetically isolated group would not have been exposed. The single women were instructed to hold boxes containing T-shirts impregnated with the scents to their noses, rate their odor quality, and then choose which they would prefer if they had to live with the scent all the time. They found most women preferred T-shirts from men with MHC alleles that had some matches with the MHC alleles they inherited from their fathers, but there was no such matching with those inherited from their mothers. Thus the women's scent preferences were consistent with avoiding extreme outbreeding. Most women did not recognize that the scent impregnating the T-shirt had come from a person, but did significantly rate the scent as pleasant. McClintock and colleagues concluded that their data indicate that paternally inherited HLA-associated odors may serve as social cues.
McClintock then outlined a mechanism by which human pheromones can regulate menstrual cycles. Her team collected samples from breastfeeding women and exposed other women to these pads or to a control substance every day. They found that exposure to a breastfeeding woman's samples desynchronized menstrual cycle lengths by altering the length of the follicular phase. An evolutionary psychology perspective of these results is that ability to detect lactation scents may indicate to another woman that it is safe to ovulate (and breed).
Dennerstein and colleagues[14] (1994) had demonstrated that heightened sexual desire precedes ovulation by 6 days. McClintock and colleagues have also demonstrated that heightened sexual desire precedes ovulation by 6 days.[15] McClintock and colleagues then showed that after 2 cycles of exposure to pads from breastfeeding women, there was a 22% increase in reported sexual desire and an equally large increase in reported sexual fantasies. She then described how "vasanas" affect mood during a social interaction and a woman's sense of sensuality. These compounds, such as androstadienone, are found in commercially marketed pheromones. In the experiment described, this compound prevented women arriving for laboratory testing from becoming irritable and from experiencing a drop in positive mood.[16] It also increased sympathetic tone and cortisol. Notably, however, the compound only had these effects when the women were tested by a man, and not by another woman. The women responded emotionally and physiologically to the man, and the androstadienone modulated their responses. They did not respond to the women, and in this social situation, the androstadienone had no effect. Thus, these compounds could well operate in daily life to modulate emotional and physiologic responses to some social situations, but not others.
Anita Clayton, President of the International Society for the Study of Women's Sexual Health, presented a State-of-the-Art Lecture, "The Status of Medical Education in Sexual Health."[17] Clayton is David C. Wilson Professor, Department of Psychiatric Medicine, University of Virginia Health System, Charlottesville. Despite the often-quoted US population-based study of sexual dysfunction finding 43% of women and 30% of men who had been sexually active in the previous year reporting sexual complaints,[18] only 25% of doctors report taking a sexual history. Inadequate training is cited as the primary reason for reluctance to inquire about female sexual dysfunction.[19] In another survey, 75% of patients believed their physicians would dismiss their sexual health concerns, with 68% believing their doctors would be embarrassed.[20] These US results were mirrored in a small UK survey of general practitioners and practice nurses, which found that these clinicians seldom took a proactive approach to sexual health issues. These were viewed as highly problematic because of sensitivity, complexity, and constraints of time and expertise.[21] It seems little wonder that clinicians are ill-prepared to deal with sexual health concerns. A survey of 101 US medical schools found that half offered 3 to 10 hours training with only one third spending 11 hours or more on sexual health.[22] Clayton reported the results of a medical student survey at the University of Virginia.[23] There was a gender-based difference in attitudes to sexual health consultations and reported levels of knowledge on the subject. Female students were more likely than male medical students to believe addressing sexual health concerns were of importance, perhaps relating to other findings indicating that female students are more likely than male students to address quality-of-life issues.[17] Male medical students described higher levels of self-reported knowledge and comfort with the area than did female students. However, when a knowledge-based test was used, there was no significant gender difference in knowledge about sexual health.
The past decade has seen major developments in the field of sexual health with the development of consensus on definitions for sexual dysfunction, validated measures, and better understanding of the underlying anatomic, psychological, and pathophysiologic mechanisms involved. Effective pharmacologic treatments for male sexual dysfunction are now available, and efforts are being made to develop and evaluate satisfactory treatments for female sexual dysfunction. Considerable education of medical students and clinicians will be needed to keep pace with growing knowledge in this area and to fulfill patient expectations.
Medscape Ob/Gyn. 2006;11(1) © 2006 Medscape
Cite this: Highlights of the International Society for the Study of Women's Sexual Health Annual Meeting - Medscape - Apr 03, 2006.
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