Measurement of Male and Female Sexual Dysfunction

Transcription

1 Measurement of Male and Female Sexual Dysfunction Raymond C. Rosen, PhD Address Department of Psychiatry, UMDNJ-Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA. Current Psychiatry Reports 2001, 3: Current Science Inc. ISSN Copyright 2001 by Current Science Inc. Measurement approaches for male and female sexual dysfunction have proliferated in recent years, spurred in large part by the development of new treatments for male and female dysfunction. In the past, physiologic measures of penile tumescence and rigidity in males, and vaginal blood flow in females, played an important role in clinical and research studies. More recently, a variety of brief, self-report measures have been developed for assessing male and female function across a variety of sexual domains (eg, desire, arousal, orgasm, satisfaction). These self-report measures have been shown to have a high degree of reliability and validity, and are sensitive to treatment interventions. Accordingly, they are widely employed in clinical trials. Daily diary or sexual event logs have similarly been developed for this purpose. Selfreport measures have been used for clinical screening purposes and for diagnostic assessment of sexual function in a number of studies. Finally, several disease-specific quality of life and treatment satisfaction measures have been developed, which are currently in widespread use in clinical trials of sexual dysfunction. Introduction Sexual dysfunctions are highly prevalent, affecting about 43% of women and 31% of men overall [1,2]. In addition to their widespread prevalence, sexual dysfunctions have been found to impact significantly on interpersonal functioning and overall quality of life in both men and women. Although less prevalent overall than sexual desire difficulties, sexual arousal difficulties in men and women have received special attention in recent years. A broad range of organic and psychologic risk factors, including diabetes, cardiovascular disease, smoking, and depression have been associated with arousal disorders in both sexes [3 ]. Effective treatment of erectile dysfunction (ED) has in turn been associated with marked improvements in mood state and quality of life [4]. Although female sexual disorders are less well understood presently, efforts are underway to refine the diagnosis and classification of these disorders [5]. An important contributing factor to this field has been the development of validated instruments for the assessment of sexual function. These instruments have been used as primary endpoints in clinical trials, as well as for clinical screening and diagnostic purposes. Not surprisingly, most attention thus far has been directed towards development of validated instruments for assessment of ED. Sexual dysfunctions in men and women are classified according to the four-phase model of Masters and Johnson [6] and Kaplan [7]. This is briefly as follows: Sexual desire, the first phase, consists of the motivational or appetitive aspects of sexual response. Sexual urges, fantasies, and wishes are included in this phase. Sexual excitement refers to a subjective feeling of sexual pleasure and accompanying physiologic changes. This phase includes penile erection in men and vaginal lubrication in women. Orgasm, or climax, is defined as the peak of sexual pleasure, with rhythmic contractions of the genital musculature in both men and women, as well as ejaculation in men. The final phase is resolution, during which a general sense of relaxation and well-being is experienced. In men, a refractory period for erection and ejaculation usually occurs during this phase. The sexual dysfunctions can be considered as alterations in one or more phases of the sexual response cycle, and this four-stage model forms the basis for diagnosis and classification of the sexual dysfunctions in DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) [8]. Measurement instruments for sexual dysfunction focus on assessing changes or disruption in one or more of these phases. Physiologic measures are generally directed at assessing arousal responses, including penile tumescence and rigidity in men [9 10] or vaginal vasocongestion in women [11], in response to endogenous events (eg, nocturnal penile erection) or exogenous stimulation (eg, visual sexual stimulation). These measures are currently used more often for research than clinical purposes. In contrast, self-report or questionnaire measures are typically multidimensional instruments that assess sexual functioning across a number of domains, including desire, arousal, orgasm, and satisfaction. Several new questionnaire instruments have been developed in recent years, which

2 Measurement of Male and Female Sexual Dysfunction Rosen 183 have played an important role in clinical trials of male and female sexual dysfunction. Clinical trials have also included daily diaries or sexual event logs for measurement of daily sexual activities. Finally, several instruments have been developed for assessment of life satisfaction or quality of life changes associated with sexual dysfunction in men and women. Physiologic Measures As noted above, several objective or physiologic measures are available for assessment of sexual arousal responses in males and females. These have typically focused on the assessment of penile erection and rigidity in men, and vaginal blood flow or vasocongestion in women. Although studies of nocturnal erection were used extensively in the 1980s and 1990s for diagnostic assessment of organic erectile dysfunction, this technique has declined in use since the availability of sildenafil. Currently, physiologic assessment methods are used predominantly for research in clinical trials of male and female sexual dysfunction. Among the methods for physiologic assessment of penile rigidity and engorgement [9,10], the most widely used is the Rigiscan system (Timm Medical Systems, Eden Prairie, MN). This method was first described by Bradley and Timm [9 ], who recommended use of the device in the home setting for monitoring of nocturnal penile tumescence and rigidity (NPTR). The device is attached to the patient's inner thigh, with two loops placed around the base and tip of the penis proximal to the coronal sulcus. Measures of radial rigidity are obtained by application of a predetermined force to each loop every 3 minutes initially, and at 30-second intervals when an increase of more than 10 mm at the base is detected. Penile rigidity is expressed as a function of displacement when the loop is tightened around the penis, and rigidity is defined in terms of penile stiffness as determined by cross-sectional response to radial compression [9 ]. Although the technique was developed originally for home monitoring of NPTR, Rigiscan recording has recently been used for in-clinic assessment of penile tumescence and rigidity in response to pharmacologic or visual sexual stimulation (VSS). Several potential limitations have been identified, the most significant of which is the assumption of equivalence between radial and axial rigidity. Although there is limited evidence for this assumption, at least one study compared measurements of axial and radial rigidity at constant corporal pressures [12]. Axial and radial rigidity were found to be functionally related, and both measures were moderately correlated with intracavernous pressure. In a comparison of Rigiscan with sleep laboratory measures of tumescence and rigidity, Licht et al. [13] reported that a base rigidity of 55% or more predicted functional erection, with a sensitivity of 85% and specificity of 91%. Other investigators have reported that tip rigidity of 70% for greater than 5 minutes provides the best cutoff for diagnostic classification [14]. Additional limitations of the device include lack of adequate standardization of normal values, limited time sampling of tumescence and rigidity, and potential intrusiveness of the device for some patients. Despite these limitations, Rigiscan assessment of penile tumescence and rigidity continues to play an important role as an objective and quantifiable measure of erectile response. Other physiologic measures of penile tumescence and rigidity include volumetric and strain-gauge plethysmography [15], and the erectiometer [16]. Volumetric plethysmography provides a highly sensitive measure of penile engorgement, which has been used extensively in studies of sexual preference or paraphilias [17 19]. However, the measurement apparatus is obtrusive and inconvenient to use, and provides no information on penile rigidity. Similarly, mercury-in-rubber and electromechanical straingauges provide sensitive measures of penile circumference change and have been widely used in laboratory studies of sexual arousal [20 22]. Finally, the erectiometer provides a crude measure of both rigidity and tumescence (circumference change). This device consists of a 2-cm wide felt band with a sliding collar fastened to one end. The felt band expands with tumescence, but requires a force of about 250 grams to initiate expansion. In this way, the device provides a combined assessment of both circumference and rigidity changes [16]. It has been used to differentiate response patterns in clinical studies with normal and sexually dysfunctional men [23,24], although the erectiometer provides less sensitivity and reliability than either the Rigiscan or mercury strain gauge devices [24]. In women, the most widely used method for assessing sexual arousal is the vaginal photoplethysmograph [11,25 ]. This device consists of a light-emitting diode and sensitive photocell detector enclosed in a tampon-sized, clear acrylic probe. The signal obtained reflects changes in the amount of light back-scattered to the photocell from the surrounding vasculature, and provides a sensitive, albeit indirect, measure of vaginal vasoengorgement. Depending upon the mode of recording, measures of vaginal blood volume or vaginal pulse amplitude (VPA) can be obtained. VPA is regarded as the more sensitive and reliable measure [25 ], and is more often used in studies of treatment outcome. Although this method has been used in a variety of research settings, it is not well standardized and there is no clinical application of the procedure to date. Other methods for assessing female genital vasocongestion, such as measures of labial temperature or clitoral blood flow, have also been described, although these are not widely used at present. Self-report Measures Self-report measures of sexual function are divided into three major categories: self-administered questionnaires,

3 184 Sexual Dysfunction daily diaries or event logs, and structured interviews. Each of these approaches has been used in recent clinical trials, although the primary emphasis in most validation studies has been on self-administered questionnaires. These measures have the potential advantage of providing standardized and relatively cost-efficient assessment of current and past sexual functioning. Patient burden is generally low, and some measures have been designed specifically for use in multicenter, clinical trials [26,27 ]. Some of these measures are also in use clinically for screening and assessment of sexual function in men or women. The questionnaire measures most widely used in men at present are listed below. International Index of Erectile Function The International Index of Erectile Function (IIEF) was designed and developed specifically for assessment of male sexual function in clinical trials [26 ]. The IIEF has been extensively validated and widely used as a measure of efficacy in clinical trials of ED agents. The instrument consists of 15 items and assesses sexual functioning in five domains: erectile function, orgasmic function, sexual desire, intercourse satisfaction, and overall satisfaction. Average scores are calculated in each of the major domains, and a simple severity algorithm is available for clinical interpretation of scores on the erectile function domain [28]. In addition to initial validation in clinical and nonclinical samples, the IIEF has recently been validated against patient s self-assessments of erectile function in clinical trials of ED [29]. A brief, five-item version of the test has also been shown to be useful for screening of patients in clinical settings [30]. Psychometric validation has demonstrated a high degree of reliability (internal consistency and testretest reliability) in both clinical and nonclinical samples. Discriminant and concurrent validity are adequate. Sensitivity and specificity (treatment responsiveness) are excellent, as has been demonstrated in recent clinical trials. Major advantages of the IIEF are its relative brevity and ease of use, inclusion of multiple domains of sexual function, and strong psychometric profile. At present, the IIEF is widely used as an international gold-standard in both clinical and research assessment of male erectile function. Brief Male Sexual Function Inventory This is an 11-item questionnaire scale that assesses several components of male sexual function, including sexual drive, erection, ejaculation, sexual problems, and overall satisfaction [25 ]. Major advantages of this scale are: 1) a relatively high degree of internal consistency and testretest reliability, 2) adequate discriminant validity for three of the domains (erectile function, problems, overall satisfaction), and 3) ease of use. Potential disadvantages are the restricted evaluation of erectile and orgasmic function, and lack of evidence concerning sensitivity or treatment responsiveness. The scale has had limited use in large-scale clinical trials of ED. Center for Marital and Sexual Health Questionnaire This brief 18-item self-report questionnaire assesses current sexual function in the areas of erection, orgasm, desire, and satisfaction [32]. Initial psychometric assessment of the instrument has been performed, although data regarding sensitivity and specificity are lacking. In this study, the measure showed adequate reliability and construct validity. It has had minimal use to date in clinical trials of ED. Female Sexual Function Index This is a recently developed, brief (19-item) self-report questionnaire which assesses sexual functioning in women in six separate domains (desire, arousal, lubrication, orgasm, satisfaction, pain) [27 ]. In addition, a total scale score can be computed according to a simple scoring algorithm. The questionnaire was developed for use in clinical trials of female sexual dysfunction and was validated in a multicenter study of women with sexual arousal disorder (n = 128) and age-matched controls (n = 131). The measure was shown to have a high degree of internal consistency and test-retest reliability, and differentiated well between the two groups. Highly significant differences were observed on all six domains between the patients and controls, indicating that the measure is very sensitive in differentiating responses between sexually dysfunctional and nondysfunctional women [27 ]. The Female Sexual Function Index is easy to administer and score and is currently being used in a number of clinical trials of female sexual dysfunction. Brief Sexual Function Index for Women This is a 22-item, multidimensional self report instrument for women that assesses sexual function in seven dimensions: sexual thoughts/desires, arousal, frequency of activity, receptivity/initiation, pleasure/orgasm, relationship satisfaction, and sexual problems. The scale also yields an overall composite score. The measure was originally validated in a normal sample of 225 women aged 22 to 55 years, 187 of whom had regular sexual partners [33]. Significant differences were observed on most dimensions of sexual function between women with and without sexual partners. More recently, the scores of the original validation sample were compared with a clinical sample of 104 women in the same age range who had undergone bilateral oophorectomy and hysterectomy [34]. This study demonstrated significantly lower scores on six of seven dimensions of sexual function and the overall composite scores of women who had undergone oophorectomy compared with controls. In particular, the dimensions of sexual desire, arousal, and frequency of activity were the most significantly different between the two groups. Most recently, this measure was found to be responsive to

4 Measurement of Male and Female Sexual Dysfunction Rosen 185 testosterone replacement therapy effects in the sample of women with bilateral oophorectomy [35]. Derogatis Sexual Function Inventory The Derogatis Sexual Function Inventory (DSFI) is a comprehensive, multidimensional measure of male and female sexual function [36]. The complete DSFI scale consists of 245 items, requiring 60 minutes or longer to complete. Ten domains of sexual function are assessed, including information, experience, drive, attitudes, psychologic symptoms, affects, gender role definition, fantasy, body image, and sexual satisfaction, in addition to a global sexual satisfaction index. The test has been psychometrically validated, and has been widely used in earlier studies in the 1980s of normal and dysfunctional individuals. Its major drawbacks are the excessive length and complexity of the instrument, which make it generally unsuitable for use in clinical trials. However, the measure remains the most comprehensive assessment questionnaire for use in both male and female subject. A structured interview form of the DSFI has recently been published [37 ]. Although the structured interview format offers potential advantages in terms of clinical validation, the measure has yet to be evaluated in large scale clinical trials. However, this measure may be of particular value in assessing response to broader (ie, nonpharmacologic) approaches to treatment of sexual dysfunction. The structured interview approach can be used for assessment of both male and female dysfunction. Daily Diaries and Event Logs Daily diaries or sexual event logs are alternative measures of sexual function that may be used to complement the use of self-report questionnaires. Event logs or daily diaries typically include assessment of variables such as intercourse frequency and satisfaction, quality of erection, and medication use. The Sexual Encounter Profile (SEP) is a six-item event log that has recently been used in a number of largescale clinical trials. In a preliminary validation study, a high degree of correlation was observed between erection and intercourse satisfaction ratings on the SEP and IIEF measures in patients with mild to moderate degrees of ED [38]. Similar event logs have been developed for use in clinical trials of female sexual dysfunction, although none of these have been systematically validated to date. Event logs have been developed specifically for clinical trial use and are not recommended for routine clinical use at present. Quality of Life and Treatment Satisfaction Measures Quality of life measures, such as physical functioning, mood state, and overall life satisfaction are routinely used in large-scale clinical trials of cardiovascular disease, cancer and other chronic illnesses. Recent clinical trials of male and female sexual dysfunction have included quality of life and patient satisfaction measures as secondary endpoints. Although these measures provide a potentially broader understanding of treatment effects, several limitations and problems are evident. First, most quality of life scales are designed for use in medically ill patients, whose disease or treatment has a noticeable impact on physical or psychologic functioning. Although sexual dysfunction patients may have deficits in some areas [39], clinical trials typically exclude patients with major medical or psychiatric disease. Additionally, most domains of quality of life assessment, such as physical functioning, cognitive performance, and global health perceptions, are unlikely to be affected by the symptoms of sexual dysfunction or its treatment. In response to the need for a more disease-specific approach, two new instruments for quality of life assessment in erectile dysfunction trials have been developed. Wagner et al. [40] report the development of a 19-item scale (QOL-MED), based on semistructured interviews with a representative sample of patients with ED. This measure has a high degree of reproducibility and internal consistency, but has received little validation in ED patients or controls. More recently, Fugl-Meyer et al. [39] have described the use of a brief, eight-item life satisfaction checklist for specific quality of life assessment in ED trials. This measure was found to differentiate between patients with ED and controls on several dimensions. Significant improvements on two scale dimensions (sexual life and overall life satisfaction) were found following successful treatment with prostaglandin injections. This measure provides a broad assessment of quality of life dimensions of potential interest in ED patients. A treatment satisfaction measure (Erectile Dysfunction Inventory of Treatment Satisfaction [EDITS]) has also recently been described [41 ]. This measure assesses patient and partner ratings of treatment satisfaction across several domains of treatment efficacy. The measure has had limited psychometric validation and has been used in recent clinical trials with sildenafil. Despite the availability of the above measures, more research is needed on treatment-specific quality of life measures for assessing sexual dysfunction outcomes in males and females. Conclusions A variety of measurement approaches are currently available for assessing male and female sexual dysfunction. Although physiologic measures, such as penile rigidity and tumescence assessment in the male, and vaginal blood flow measures in women, have been used in the past, these are less frequently used at present. Rather, a number of recent self-report measures have been developed for multidimensional assessment of sexual function in both men and women. Several of these measures have demonstrated adequate psychometric properties, including test-retest reliability, internal consistency and discriminant validity.

5 186 Sexual Dysfunction Daily diary and sexual event log measures have also been developed for use in clinical trials of male and female sexual dysfunction. These are typically used in conjunction with self-report questionnaire measures. Only one structured interview method has been described in the literature thus far, and this method has not been widely used to date. Finally, several disease-specific quality of life and treatment satisfaction measures have been described, which are being increasingly used in clinical trials of male and female dysfunction. Overall, these measures have contributed significantly to the development of this field in recent years. References and Recommended Reading Papers of particular interest, published recently, have been highlighted as: Of importance Of major importance 1. Laumann EO, Gagnon JH, Michael RT, Michaels S: The social organization of sexuality. Chicago: University of Chicago Press; Feldman HA, Goldstein I, Hatzichrisou DG, et al.: Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. J Urol 1994, 151: Lauman EO, Paik A, Rosen RC: Sexual dysfunction in the United States: prevalence and predictors. JAMA 1999, 281: This article reviews the prevalence and major risk factors for sexual dysfunction in a large sample of men and women in the United States. Psychosocial and medical risk factors are equally important as risk factors for sexual dysfunction. 4. Seidman S, et al.: (In press) 5. Basson R, Berman J, Burnett A, et al.: Report on the international consensus development conference on female sexual dysfunction: definitions and classifications. J Urol 2000, 163: Masters WH, Johnson VE: Human sexual inadequacy. Boston: Little, Brown; Kaplan HS: The new sex therapy. New York: Brunner Mazel; American Psychiatric Association: Diagnostic and statistical manual of mental disorders, edn 4. Washington, DC: American Psychiatric Press; Bradley WE, Timm GW, Gallagher JM, et al.: New method for continuous measurement of nocturnal penile tumescence and rigidity. Urology 1985, 26: Levine LA, Lenting EL: Use of nocturnal penile tumescence and rigidity in the evaluation of male erectile dysfunction. Urol Clin North Am 1995, 22: Sintchak G, Geer JH: A vaginal plethysmography system. Psychophysiology 1975, 12: Frohib DA, Goldstein I, Payton TR, et al.: Characterization of penile erectile states using external computer-based monitoring. J Biomech Eng 1987, 109: Licht MR, Lewis RW, Wollan PC, Harris CD: Comparison of Rigiscan and sleep laboratory nocturnal penile tumescence in the diagnosis or organic impotence. 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Urology 1997, 49: The International Index of Erectile Function is the most widely used self-report questionnaire for assessing sexual dysfunction in males. The initial validation and use of the questionnaire is described in this article. 27. Rosen RC, Brown C, Heiman J, et al.: The Female Sexual Function Index (FSFI): a multidimensional self-report instrument for the assessment of female sexual function. J Sex Mar Ther 2000, 26: A new self-report questionnaire has been developed for assessment of female sexual dysfunction. The questionnaire assesses six domains of sexual function and has been validated in a sample of sexually dysfunctional women. 28. Cappelleri JC, Rosen RC, Smith MD, et al.: A diagnostic evaluation of the Erectile Function domain of the International Index of Erectile Function (IIEF). 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6 Measurement of Male and Female Sexual Dysfunction Rosen Derogatis LR, Melisaratos N: The DSFI: a multidimensional measure of sexual functioning. J Sex Marital Ther 1979, 5: Derogatis LR: The Derogatis Interview for Sexual Functioning (DISF/DISF-R): an introductory report. J Sex Marital Ther 1997, 23: Rosen RC: Sexual function assessment in the male: physiological and self-report measures. Intl J Impot Res 1998, 10(Suppl 2):S59 S Fugl-Meyer AR, Lodnert G, Branholm I-B, Fugl-Meyer KS: On life satisfaction in male erectile dysfunction. Intl J Impot Res 1997, 9: Wagner TH, Patrick DL, McKenna P, Froese PS: Cross-cultural development of a quality of life measure for men with erectile difficulties. Qual Life Res 1996, 5: Althof SE, Corty EW, Levine SB, et al.: EDITS: development of questionnaires for evaluating satisfaction with treatments for erectile dysfunction. Urology 1999, 53: This is the treatment satisfaction questionnaire used widely in the sildenafil trials. It has adequate psychometric properties.