Understanding and diagnosing sexual dysfunction: recent progress through psychophysiological and psychophysical methods.

The psychophysiological method has been applied to the study of human sexual response for well over three decades. The value of this method in providing an objective, integrated approach to the understanding of sexual response, and more specifically sexual dysfunction, is presented. Selected results from recent studies using this methodology illustrate the complex relationships that emerge among cognitive, affective, and physiological components of the sexual response. In addition, data from a systematic study of the use of psychophysiological procedures as an aid in differential diagnosis are given as evidence that this methodology offers a further strategy for assessing problems such as erectile dysfunction and premature ejaculation. Finally, recent findings utilizing sensory psychophysical procedures which relate subjective penile thresholds to sexual response and dysfunction are reviewed. Such procedures also study the interaction of physical/physiological systems with psychological events, and as such may be considered relevant to understanding the relationship between psychological aspects of sexual response.

Sexual arousability and the menstrual cycle.

We have repeated a study of the objective (labium minus temperature) and subjective (semantic scales) changes in sexual arousability over the menstrual cycle to erotic video stimulation in 20 women with natural cycles. We extended the study with concomitant vibrotactile stimulation of the clitoral region. In an earlier study women tested for the first time in their follicular phase were sexually more aroused (as indicated by greater increase in labium minus temperature) than women tested for the first time during their luteal phase. When these women were retested in their alternative phase of the menstrual cycle, those who were then follicular did not score higher than those who were then luteal. We then postulated the involvement of a cognitive or conditioned phenomenon which was responsible for the women's repeating their initial phase-dependent response when tested the second time in their alternative phase of the cycle. Identical results were obtained in the present study as far as sexual arousability is concerned during the first test, i.e. follicular women generally scored higher than luteal women; this difference in response persisted during the second test. Concomitant vibrotactile stimulation had no effect on labium minus temperature change but raised subjective sexual arousal and caused a 'more pleasurable' response to the erotic video. Subjective sexual and subjective genital arousal were positively correlated, but neither was significantly correlated with labium minus temperature change. The relationship between menstrual cycle phase and sexual arousal was further substantiated by the reported greater increase in sexual desire after the first erotic video in follicular women than in luteal women. This increased desire, as well as more erotic fantasies, persisted during the next 24 h. In conclusion, studies into effects of menstrual cycle phase on sexual arousability in the laboratory should seriously consider the possible learning and conditioning effects as suggested by the present investigation.

Endocrine, psychological and genital response to sexual arousal in men.

The endocrine, genital, and cognitive--affective responses of sexually functional men were compared under sexually arousing and non-arousing conditions. Sexually aroused subjects showed significantly higher serum luteinizing hormone concentrations than non-aroused subjects. Testosterone concentration was correlated with higher levels of penile response, but it did not prime further sexual arousal. Cortisol and prolactin concentrations decreased in both groups, more in the non-aroused group, and appeared to both inhibit and facilitate sexual response, depending on the level of anxiety reported by the subjects. Cortisol was correlated with self-reported worry, and testosterone with relaxation. These results support a multidimensional approach to the endocrine study of sexual arousal that includes both cognitive and genital response components.

Males located caudally in the uterus affect sexual behavior of male rats in adulthood.

It has been suggested that the sexual differentiation of female rats is affected by androgens from male fetuses in the uterine horn (intra-uterine position phenomenon). Effects of adjacent males, as well as of males located caudally in the uterus have been reported. The present study investigated whether male rats, like females, are affected by the presence of either caudal or adjacent male littermates. When tested in adulthood for sexual behavior, males that had male fetuses located caudally in the uterine horn showed shorter latencies to the first mount or intromission and shorter latencies to ejaculation, and exhibited more mounts and intromissions per minute than males that lacked caudal male siblings in the uterus. The presence of adjacent males did not significantly affect the parameters studied in this experiment.

Penile sensitivity in men: a composite of recent findings.

OBJECTIVES: To present, in standardized form, age- and dysfunction-related data from 13 studies on vibrotactile penile epiglandal thresholds in men to allow cross-study comparisons, a capability previously prevented by the use of varying methods and units of measurement. METHODS: On the basis of the summarization and standardization of multiple studies located through online searches of bibliographic data bases, penile sensory thresholds were first plotted as a function of age, and then as a function of dysfunctional or disease status. In a third plot, both age- and dysfunction-related differences were illustrated within a single plot. RESULTS: An increasing curvilinear threshold as a function of age was confirmed in the pattern derived from multiple studies. Furthermore, even when controlling for age, penile thresholds of men with erectile dysfunction lay one or more standard deviations above those of sexually functional counterparts, and this deviation became even higher during penile tumescence. When relationships among age, dysfunctional/disease status, and penile threshold were examined simultaneously, potential compounding effects of age and dysfunction emerged. CONCLUSIONS: From a research perspective, standardized information on penile vibrotactile thresholds will facilitate ongoing study aimed at elucidating the role of penile sensitivity to both erectile and ejaculatory response. From a clinical perspective, standardized information on populations of sexually functional and dysfunctional men may assist in a preliminary differential diagnosis.

A psychophysiological approach to assessing premature ejaculation.

A hierarchical psychophysiological model is described that provides a working framework for clinicians interested in addressing issues related to premature ejaculation (PE). Within this framework, psychophysiological laboratory analysis, used in conjunction with conventional self-report measures, has potential to contribute both to the measurement and understanding of premature ejaculation and to the assessment of treatment procedures aimed at alleviating PE.

Sexual response in men with inhibited or retarded ejaculation.

Inhibited ejaculation (IE) is a poorly understood male sexual dysfunction having both somatic and psychological etiologies. This study investigated sexual response in 25 IE men with no probable somatic cause. Using a standard psychophysiological assessment procedure, these men were compared with sexually functional and other dysfunctional groups on two measures of sexual response: erectile response and self-reported sexual arousal. Within the sample of IE men, sexual response was investigated as a function of both diagnostic classification and relationship factors. Differences occurred between IE men and the other groups on erectile response and self-reported sexual arousal during psychosexual stimulation in the lab, with IE men reporting lowest levels of sexual arousal. Within the IE group, diagnostic classifications and relationship variables were also related to self-reported sexual arousal. These findings suggest that inhibited arousal may be fairly common among IE men having no apparent somatic etiology, and further that several specific relationship factors may provide potential strategies for enhancing arousal in these men.

The use of vibrotactile stimulation for determining sexual potency in the laboratory in men with erectile problems: methodological considerations.

Vibrotactile stimulation, when used in combination with visual sexual stimulation, has been shown to enhance erectile response in sexually functional men. The present study attempted to describe a diagnostic methodology, including the development and application of a new mini-vibrator, that might enhance penile response in men with erection problems. Tests on 78 men with either erectile dysfunction (ED), or a combination of erectile dysfunction and premature ejaculation (ED+PE), showed that vibratory stimulation together with an erotic video (EV+VT), produced greater penile response than the erotic video alone (EV). The new mini-vibrator was more effective than a previously used model, and produced clinically significant increases in erectile response in ED+PE men. In addition, the enhancing effect of the combined stimulation on self-reported penile response was greater when it followed EV than when it preceded it. The use of vibrotactile stimulation and visual sexual stimulation together may therefore assist in determining the potential sexual potency of men experiencing erection problems during the process of differential diagnosis.

Predicting responsiveness to the treatment of rapid ejaculation with 25 mg clomipramine as needed.

Clomipramine (25 mg) taken as needed increases ejaculatory latency in men with rapid ejaculation (RE), although only about half the men treated respond to this regimen. It would therefore be clinically advantageous to know the patient's potential responsiveness to an 'as needed' regimen prior to treatment. The present study attempted to identify a priori factors that might enable prediction of patients' response or nonresponse to 'as needed' clomipramine. Variables relevant to rapid ejaculation were examined in 23 men with RE, 12 of whom had responded to clomipramine. Logistic regression indicated that three factors assessed prior to treatment--initial ejaculation latency, overall sexual satisfaction, and ejaculation frequency each week--significantly improved the prediction of responsiveness to this treatment regimen. Specifically, RE men with initial ejaculatory latencies over 60 s, self-reported sexual satisfaction of 5 or higher (on a seven-point scale), and ejaculation frequency of twice or more weekly were more likely to benefit from 25 mg 'as needed' clomipramine. As such, men meeting these criteria might be considered for this treatment regimen. Those not matching these characteristics might better be considered for 20 or 30 mg clomipramine given on a daily basis.

Intracavernosal self-injection therapy in men with erectile dysfunction: satisfaction and attrition in 119 patients.

This study describes a 12-24 month follow-up on 119 ED patients in an attempt to understand satisfaction with and dropout from ICI use. Results indicate 40% attrition, attributed primarily to a lack of efficacy of ICI, but also to spontaneous return of erectile function and to negative reactions surrounding the injection procedure. Multivariate analyses indicated that ICI dropouts were more likely to have co-existing premature ejaculation, low responses during psychophysiological screening, a lack of spontaneous erections prior to ICI, and an etiology that included an organogenic component. These same factors, along with low satisfaction with their sex life, were related to attrition due specifically to a lack of drug efficacy. In contrast, attrition due to recovery of spontaneous erections was associated with high sexual satisfaction. Among ongoing users, dissatisfaction was associated with higher age, shorter erections during ICI use, and low satisfaction with sex life. These findings identify a number of factors related to attrition and satisfaction, emphasizing the importance of specifying the cause for ICI attrition and, demonstrating that a substantial portion of patients who dropout do so for positive reasons.

Genital and psychoaffective response to erotic stimulation in sexually functional and dysfunctional men.

To understand the sexual response patterns of men with premature ejaculation and erectile dysfunction, the authors compared genital and affective responses of sexually functional and dysfunctional men with 3 types of sexual stimulation: an erotic video, penile vibrotactile stimulation, and a combination of both. Genital response differed across both groups and stimulus conditions, with an interactive effect indicating that groups showed different response patterns depending on the stimulation. Affective responses also differed across groups and interacted with stimulus conditions. The combination genital and affective response was superior to either alone in distinguishing men with no sexual problems from those with erectile or ejaculatory problems (or both). These factors were particularly useful in discriminating men with premature ejaculation from those with combined premature ejaculation and erectile dysfunction.

Effect of constant light on parturition and postpartum reproduction in the rat.

Light-dark (LD) cyclicity contributes to a number of reproductive events in the rat, including estrus cyclicity, and the timing of parturition and postpartum estrus. Constant light (LL) disrupts the female's cyclicity, and fertility is typically diminished. To ascertain whether constant light similarly diminishes the fertility of postpartum females, LL and LD animals were compared over three successive pregnancies on several reproductive measures including parturition, postpartum estrus and spontaneous ovulation, the timing of estrus relative to parturition, and the number, body weights, and viability of offspring. While the 24 h pattern of parturition differed for LL and LD groups, postpartum estrus and ovulation occurred reliably in both groups. The LD group showed greater variation in the birth-estrus interval, the result of a delayed estrus in those females giving birth late in the light phase. The likelihood of spontaneous ovulation and overall successful reproduction was high for both groups. Thus, unlike the cycling female, the fertility of the postpartum female is relatively unaffected by constant light. As such, these findings suggest that LD cyclicity is not critical for postpartum ovulation and estrus.

Plasma testosterone in fetal rats and their mothers on day 19 of gestation.

Plasma testosterone levels were higher in pooled samples from male fetuses than from female fetuses on day 19 of pregnancy. Plasma testosterone from female fetuses with males located caudally in the uterus was higher than from females that lacked such males. Testosterone level of both male and female fetuses was correlated with maternal testosterone. No correlation was found between maternal testosterone and number of males in the litter, male-to-female ratio, or litter size. These results corroborate earlier findings of a sex difference in plasma testosterone levels on fetal day 19 in rats, and provide support for the hypothesis that female rats receive androgens from males located caudally in the uterus. No evidence was found that testosterone of pregnant females is affected by the sex ratio or size of her litter.

Affective and physiological sexual response patterns: the effects of instructions on sexually functional and dysfunctional men.

To more clearly characterize the patterns of cognitive-affective and physiological responses concomitant with male sexual dysfunction, the present study compared 14 sexually dysfunctional and 16 sexually functional men. All individuals listened to two sexually explicit tapes and engaged in a self-generated fantasy, while genital, heart rate and scaled cognitive affective responses were recorded. Two types of instructions, a performance demand set and a non-demand sensate focus set, preceded the erotic tapes in counterbalanced order. As predicted, dysfunctional men showed less genital tumescence to tapes preceded by the demand than the non-demand instructions. Contrary to expectation, functional men showed greater penile tumescence to the tapes preceded by demand instructions. Self-reported sexual arousal did not follow the penile tumescence pattern but instead indicated that the dysfunctional sample was significantly less subjectively aroused to the tapes and fantasy. There were other significant differences between the groups. Dysfunctional men showed greater general psychological distress, as measured by the SCL-90, including elevated somaticism, anxiety and depression scores. During the experimental session, dysfunctional men also evidenced greater awareness of a variety of physiological responses, as well as more negative and fewer positive cognitive-affective states. These data are discussed in terms of the interaction of affective and physiological responses, differences in contextual meanings of instructional sets given the presence of a dysfunction, and theoretical and clinical conceptualizations of male sexual functioning.

Self-reported and genital arousal changes in sexually dysfunctional men following a sex therapy program.

This investigation examined the question of whether differences in psychophysiological and self-reported sexual response between sexually dysfunctional men and sexually functional men are reduced following treatment in a sex therapy program. Patterns of sexual responding before and after treatment in nine men with erectile difficulties and/or low sexual desire were compared with those of nine age-matched controls tested at the same intervals. Results indicated: (1) increased genital and self-reported response during the post-test in dysfunctional men but not in controls; (2) conditions eliciting performance demand produced less inhibition during the post-test in dysfunctional men; and (3) moderate correlations in dysfunctional men between clinically-assessed improvement in sexual functioning and actual changes in penile and self-reported arousal from the first to the second laboratory session. The implications of these data for the understanding of variables responsible for improved sexual functioning, and therefore, to clinical assessment and therapy, are discussed. Possible cognitive strategies are provided to account for discrepancies in self-reported and physical sexual arousal in dysfunctional subjects, and the efficacy and limitations of using psychophysiological methods in studying sexual response in dysfunctional men are suggested.

Ejaculatory latency and control in men with premature ejaculation: an analysis across sexual activities using multiple sources of information.

OBJECTIVE: Men with premature ejaculation (PE) exhibit diminished control over and short latency to ejaculation. The present study attempted to delineate further characteristics of men with PE and to address a number of presumed hypotheses regarding the etiology of this disorder. METHODS: Twenty-six men with PE were compared with an age-matched group of 13 sexually functional men on multiple indices of erectile and ejaculatory response during coital and masturbatory activities. These data were collected through retrospective, prospective, and laboratory methods. RESULTS: Psychophysiological testing indicated greater ejaculatory vulnerability to penile stimulation, although not visual erotic stimulation, in PE men than functional controls. PE men also showed subtle anomalies in the way they perceived their somatic response. The correlation between measures of ejaculatory latency and control was positive and high for intercourse, but low or even negative for masturbation. Whereas functional men showed consistency in ejaculatory latency over coital and masturbatory activities, PE men exhibited much shorter latencies during coitus than masturbation. Data collected under various methodologies (retrospective, prospective, and laboratory) showed greater consistency among sexually functional subjects; and preliminary analysis of laboratory data suggests psychophysiological methodology is as effective in differentiating dysfunctional from functional men as prospective and retrospective methodologies. CONCLUSION: Although ejaculatory latency and control tend to be related, these measures are not always stable over different kinds of sexual activity or using different methods of data collection. Psychophysiological methodology is effective in differentiating group membership (PE vs. control), but does not predict individual ejaculatory responses measured prospectively.

8-OH-DPAT interacts with sexual experience and testosterone to affect ejaculatory response in rats.

Studies investigating the effect of 8-OH-DPAT (DPAT) on male sexual response have typically used subjects having variable sexual experience and levels of testosterone, factors known to independently influence male sexual behavior. This experiment examined the role of these two variables in the mediation of DPAT effects on sexual behavior. One hundred and six castrated males, half of whom received sexual experience, were tested with an effective dose of 8-OH-DPAT (0.1 mg/kg) or saline. In addition, males were tested under one of three regimens of testosterone. Results indicated that DPAT and testosterone exerted independent effects on ejaculatory measures, and along with sexual experience, showed interactive effects as well. When testosterone (T) levels were substantially below normal, DPAT showed no effect. When T reached threshold levels, the DPAT effect was limited to sexually experienced males. At high T levels, both experienced and naive males exhibited strong effects from DPAT. In contrast with ejaculatory measures, mounting and intromitting behaviors were relatively unaffected by DPAT. These results emphasize the importance of specifying both the animal's sexual history and its testosterone profile in studies investigating pharmacological effects on sexual response.

Testing and analytical procedures for laboratory studies involving nonresponders during a limited observation period: an illustration using male sexual behavior in rats.

In many laboratory studies, a subpopulation of subjects fails to exhibit the response under investigation during the period of observation. For example, within any population of male rats, there is significant variation in the expression of sexual behavior in the presence of a receptive female. Some males may never display the full sequence of behaviors leading to ejaculation within the typical time frame of the testing session, with the resulting lack of behavioral response presenting problems in the analysis of the data. Conventional strategies range from screening such males from the study or dropping them from the analysis to constructing new variables based on estimates from existing parameters or increasing the length of the test session to capture sexual responses in a greater portion of males. Herein, we present an alternative strategy for analyzing data where outcomes are absent due to the limited observation period. Survival regression analysis enables inclusion of all subjects in the analysis whether or not they have shown the behavior of interest. Use of such a strategy not only has potential to reveal new results but also guards against bias from excluding nonresponders from the study or dropping more males from one experimental condition than another. Furthermore, this procedure can be helpful in generating the conditional probability (increase, decrease, or constant) of the response with the passage of time based on the hazard function and in estimating parameters for establishing an optimal behavioral test length for future studies.

Genital and heart rate response to erotic stimulation in men with and without premature ejaculation.

This study compared genital and penile response patterns in men with and without premature ejaculation (PE) so as to identify the potential anomalous psychosomatic relationships among men with PE. Genital and heart rate response profiles of 25 men with PE were compared with those of 13 age-matched sexually functional counterparts during visual sexual stimulation presented in combination with vibrotactile penile stimulation. Although no differences were found between men with PE and controls on maximum penile circumference change, overall penile response was significantly lower in the PE group and PE men who ejaculated during the session exhibited shorter latencies to maximum circumference change. Furthermore, significant differences were found between groups in patterns of heart rate. These findings indicate differences in physiological responses between men with PE and sexually functional counterparts during erectile tumescence and progression toward ejaculation. Such differences might be explained by 'premature' sympathetic activation during the sexual response cycle in men with PE, thereby diminishing parasympathetically controlled penile response and triggering sympathetically mediated seminal emission prematurely.