Automated Artifact-Detection Procedure for Vaginal Photoplethysmography

Short-Term Dorsal Genital Nerve Stimulation Increases Subjective Arousal in Women With and Without Spinal Cord Injury: A Preliminary Investigation

OBJECTIVES

Female sexual dysfunction (FSD) affects an estimated 40% of women. Unfortunately, FSD is understudied, leading to limited treatment options for FSD. Neuromodulation has shown some success in alleviating FSD symptoms. We developed a pilot study to investigate the short-term effect of electrical stimulation of the dorsal genital nerve and tibial nerve on sexual arousal in healthy women, women with FSD, and women with spinal cord injury (SCI) and FSD.

MATERIALS AND METHODS

This study comprises a randomized crossover design in three groups: women with SCI, women with non-neurogenic FSD, and women without FSD or SCI. The primary outcome measure was change in vaginal pulse amplitude (VPA) from baseline. Secondary outcome measures were changes in subjective arousal, heart rate, and mean arterial pressure from baseline. Participants attended one or two study sessions where they received either transcutaneous dorsal genital nerve stimulation (DGNS) or tibial nerve stimulation (TNS). At each session, a vaginal photoplethysmography sensor was used to measure VPA. Participants also rated their level of subjective arousal and were asked to report any pelvic sensations.

RESULTS

We found that subjective arousal increased significantly from before to after stimulation in DGNS study sessions across all women. TNS had no effect on subjective arousal. There were significant differences in VPA between baseline and stimulation, baseline and recovery, and stimulation and recovery periods among participants, but there were no trends across groups or stimulation type. Two participants with complete SCIs experienced genital sensations.

CONCLUSIONS

To our knowledge, this is the first study to measure sexual arousal in response to short-term neuromodulation in women. This study indicates that short-term DGNS but not TNS can increase subjective arousal, but the effect of stimulation on genital arousal is inconclusive. This study provides further support for DGNS as a treatment for FSD.

Acute dorsal genital nerve stimulation increases subjective arousal in women with and without spinal cord injury: a preliminary investigation

Introduction

Female sexual dysfunction (FSD) impacts an estimated 40% of women. Unfortunately, female sexual function is understudied, leading to limited treatment options for FSD. Neuromodulation has demonstrated some success in improving FSD symptoms. We developed a pilot study to investigate the short-term effect of electrical stimulation of the dorsal genital nerve and tibial nerve on sexual arousal in healthy women, women with FSD, and women with spinal cord injury (SCI) and FSD.

Methods

This study consists of a randomized crossover design in three groups: women with SCI, women with non-neurogenic FSD, and women without FSD or SCI. The primary outcome measure was change in vaginal pulse amplitude (VPA) from baseline. Secondary outcome measures were changes in subjective arousal, heart rate, and mean arterial pressure from baseline. Participants attended one or two study sessions where they received either transcutaneous dorsal genital nerve stimulation (DGNS) or tibial nerve stimulation (TNS). At each session, a vaginal photoplethysmography sensor was used to measure VPA. Participants also rated their level of subjective arousal and were asked to report any pelvic sensations.

Results

We found that subjective arousal increased significantly from before to after stimulation in DGNS study sessions across all women. TNS had no effect on subjective arousal. There were significant differences in VPA between baseline and stimulation, baseline and recovery, and stimulation and recovery periods among participants, but there were no trends across groups or stimulation type. Two participants with complete SCIs experienced genital sensations.

Discussion

This is the first study to measure sexual arousal in response to acute neuromodulation in women. This study demonstrates that acute DGNS, but not TNS, can increase subjective arousal, but the effect of stimulation on genital arousal is inconclusive. This study provides further support for DGNS as a treatment for female sexual dysfunction.

Reduction in genital sexual arousal varies by type of oral contraceptive pill

BACKGROUND

Although oral contraceptive pills (OCPs) have been associated with decrements in self-reported genital arousal and vaginal lubrication, 1,2 little is known about how these outcomes vary across types of OCPs.

AIM

The present study examined differences in physiological lubrication and vaginal blood flow, as well as rates of self-reported vulvovaginal atrophy and female sexual arousal disorder, among women using OCPs with varying androgenic properties.

METHODS

Participants in this study were 130 women: 59 naturally cycling control women, 50 women taking androgenic OCPs, and 21 women taking antiandrogenic OCPs. Participants watched sexual films while their sexual arousal responses were measured, completed questionnaires, and participated in a clinical interview.

OUTCOMES

Vaginal blood flow, vaginal lubrication, self-reported vulvovaginal atrophy, and female sexual arousal disorder were assessed.

RESULTS

Results indicated deficits in vaginal pulse amplitude and lubrication for women taking either form of OCP, with marked inhibitory effects found in women taking antiandrogenic OCPs. Rates of self-reported vulvovaginal atrophy and female sexual arousal disorder were also significantly greater in the antiandrogenic group compared with the control group.

CLINICAL IMPLICATIONS

It is recommended that prescribing clinicians consult patients on such physiological effects of OCPs.

STRENGTHS AND LIMITATIONS

To our knowledge, this was the first study to compare multiple measures of physiological sexual arousal across groups of women taking OCPs with varying hormonal profiles. Because all OCPs included in this study contained low doses of ethinylestradiol, we were able to identify the specific effects of the androgenic properties on women's sexual arousal responses. However, the self-administered lubrication test strip was subject to user error. Additionally, the generalizability of findings is limited by the largely heterosexual and college-aged sample.

CONCLUSION

Compared with naturally cycling women, women taking OCPs that contain antiandrogenic progestins experienced decreased vaginal blood flow and lubrication as well as higher rates of self-reported vaginal bleeding and female sexual arousal disorder.

Sexual violence history predicts changes in vaginal immune parameters during sexual arousal

OBJECTIVE

To examine the influence of sexual arousal on vaginal mucosal inflammatory cytokine and antibody production in healthy women with and without histories of childhood and/or adult sexual violence.

METHODS

Ninety-one premenopausal healthy women (ages 18-42) attended a single laboratory session in which they provided vaginal fluid samples before and after viewing one neutral and one erotic film. While viewing the films, participants' vaginal sexual arousal was recorded using vaginal photoplethysmography.

RESULTS

Of the 91 participants, 41 (45%) reported no history of sexual violence, 17 (19%) reported a history of childhood sexual abuse (CSA) only, 19 (21%) reported a history of adult sexual assault (ASA) only, and 10 (11%) reported a history of both CSA and ASA, with 4 participants choosing not to provide information on their sexual violence history. For women with a history of ASA but not CSA, there was a significant increase in vaginal IL-1β following arousal, while for women with a history of CSA (with or without ASA), there was a significant decrease. Women without CSA histories had a significant increase in vaginal IgA following sexual arousal, while women with CSA histories had a decrease.

CONCLUSION

Sexual arousal possibly plays a role in modifying vaginal immune responses in young, healthy women. Moreover, these effects may vary depending upon sexual assault histories, such that relative to women without assault histories, women with a history of early life sexual trauma showed significantly altered vaginal immune responses following sexual arousal. If replicated, these findings may help explain the increased risk for sexually transmitted infections observed among women with sexual assault histories.

Can the Vaginal Photoplethysmograph and Its Associated Methodology Be Used to Assess Anal Vasocongestion in Women and Men?

Forty years ago, researchers documented changes in vascular and muscular activity within the anal canal of women and men who engaged in sexual self-stimulation. Vascular changes were assessed using a photoplethysmograph that aimed to detect changes in pelvic vasocongestion. An important advantage of detecting sexual response within the anal canal is that the device, its anatomical placement, and the data output are identical for women and men, therefore facilitating gender comparisons of response patterns. In this study, the vaginal photoplethysmograph (VPP), the most common measure of genital response in women, was administered intra-anally as an anal photoplethysmograph (APG) to examine its validity and sensitivity as an indicator of sexual response. The final sample comprised 20 women and 20 men who were exposed to 12, 90-s sexual and nonsexual film clips while their APG responses were recorded. Participants also rated their sexual arousal and affective responses to the stimuli. There was evidence that APG responses were specific to sexual stimuli and were sensitive to erotic intensity in women. The degree of discrimination between sexual and nonsexual stimuli was lower in men. Unlike most sexual psychophysiological studies, the positive correlation between physiological and self-reported sexual arousal was stronger in women than in men. There was a relatively high number of data artifacts and the waveform morphology was uncharacteristic of that typically observed with VPP. The potential role of anal musculature interference on the APG signal is discussed, as well as avenues for future research.

The Relationship between Subjective and Physiological Sexual Arousal in Women with and without Arousal Concerns

Whereas laboratory studies frequently report low correlations between women's physiological and subjective sexual arousal (i.e., concordance), research employing advanced statistical techniques reveals striking between-person variability in this relationship. Moreover, previous research has shown that interoception (i.e., the awareness of changes within the body) influences concordance in women, though how this effect varies by sexual function is yet unknown. The present study used multilevel modeling to examine concordance in women with (n = 27) and without (n = 28) sexual arousal concerns and explored how concordance varies as a function of interoception. Women viewed a sexual film while their arousal responses were measured and then completed a self-report measure of interoception. A significant relationship emerged between physiological and subjective sexual arousal, in addition to tremendous between-person variability across both groups. Several aspects of interoception moderated concordance (p's between 0.0008 and 0.03), and this pattern varied across groups. Given this variability even in absence of sexual arousal concerns, these findings question the utility of using concordance as a clinical outcome in treatment research. Individual differences in interoception may have implications for treatment matching.