SANTA FE, N.M. — While the most recent edition of the Diagnostic and Statistical Manual of Mental Disorders defines only one type of female sexual arousal disorder, there is now physiologic evidence that there are at least two subtypes of the disorder, Lori A. Brotto, Ph.D., reported during the annual meeting of the Society for Psychophysiological Research.
For a diagnosis of female sexual arousal disorder (FSAD), DSM-IV-TR requires “persistent or recurrent inability to attain … an adequate lubrication-swelling response of sexual excitement.”
Although some women with the disorder do complain mostly of genital impairment, others report that while their body becomes aroused, they don't become aroused psychologically.
In a study involving 70 women, Dr. Brotto of the University of Washington in Seattle examined 8 women reporting the genital subtype of FSAD, 26 reporting the subjective subtype, and 36 control subjects reporting no difficulties in becoming aroused.
All of the women watched neutral and erotic films while their vaginal pulse amplitude—a reliable measure of genital arousal—was measured by a vaginal photoplethysmograph. The women in the study also provided a continuous measure of their subjective responses by changing the position of a lever.
The women underwent testing on two occasions, once after laboratory-induced hyperventilation. In previous studies, Dr. Brotto determined that in normal women, hyperventilation, which activates the sympathetic nervous system, increased the change in vaginal pulse amplitude between neutral and erotic films.
In both the control women and the women with FSAD, the erotic film resulted in significant increases in vaginal pulse amplitude.
All of the participants responded to the erotic film with perceived autonomic arousal and perceived physical arousal, but the women with FSAD reported less arousal, the researchers said.
Overall, women in the control group reported greater arousal and more positive affect than did women with FSAD.
The vaginal photoplethysmography supported the reports of women who had complained of problems with genital arousal. Those women showed no significant increase in vaginal pulse amplitude in response to the erotic films.
Women who had complained of a subjective arousal disorder, on the other hand, did show evidence of significant genital arousal, according to the study.
While the women in the control group and the women with the genital arousal subtype of FSAD showed a potentiated physiologic response to the erotic film after hyperventilation, the women with the subjective subtype of FSAD showed a significantly smaller physiologic response after hyperventilation than before.
Hyperventilation resulted in no significant changes in the subjective measures in either the control or the FSAD women. The study finding suggests that the effect of this manipulation occurred exclusively at a physiologic level and was not due to some distraction or other psychological causes.
One implication of the study is that women with the subjective subtype of FSAD may have differences in basal sympathetic tone, compared with women with the genital subtype or women without FSAD, according to Dr. Brotto and the other researchers.
Another implication of the study findings is that vaginal photoplethysmography, now exclusively a laboratory technique, may find a place as a diagnostic tool used to differentiate between FSAD subtypes.
Dr. Brotto pointed out that other data from her lab suggest that photoplethysmographic patterns can serve as an indicator of which women will respond to vasoactive medications with increased arousal.