Sexual Dysfunction and Disability

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Chapter 31 Sexual Dysfunction and Disability

Sexuality is one of the most complex aspects of human life, with a myriad of organic and psychosocial influences. It is a topic that is difficult to discuss in a physician’s office. It often promotes feelings of embarrassment and discomfort on the part of the patient and the practitioner, and yet is one of the most important determinants of quality of life. Disability often has a dramatic negative impact on sexual functioning, but it does not change the inherent human yearning for intimacy, companionship, and physical satisfaction that sexuality affords. The physiatrist who has the courage and knowledge to openly address issues of sexual dysfunction with patients will enrich their lives immeasurably.

The goal of this chapter is to provide an overview of sexual function and dysfunction, with an emphasis on the sexual challenges faced by people with disabilities. Great care has been taken to give equal treatment to the sexual dysfunctions of both men and women, as female sexuality is too often overlooked, both in society and in the medical literature.

Sexual Response and Behavior

Human Sexual Response

The classic model of human sexual response was formulated by Masters and Johnson ¹⁴⁶ in the 1960s based on a study of 600 able-bodied men and women. The model depicts women and men as having similar sexual responses throughout four phases: excitement, plateau, orgasm, and resolution (Table 31-1).¹⁴⁸ In the Masters and Johnson model, men tend to pass through each phase faster than women and achieve only one orgasm per cycle, often with a very short plateau phase. Women can achieve multiple orgasms in the same sexual response cycle. Masters and Johnson¹⁴⁶ also noted that women could also become “stalled” at the plateau phase and then pass straight to resolution without achieving orgasm.

Table 31-1 Masters and Johnson Model of Sexual Response

Excitement

• Associated with the senses, memory, and fantasy

• Increases in heart rate, blood pressure, respiratory rate

• Myotonia develops late in the arousal phase

• Men: Engorgement of the corpus cavernosa of the penis, testicular elevation, scrotal skin flattening, possible nipple erection

• Women: Clitoral enlargement, vaginal lubrication, constriction of the lower third of the vagina with dilation of the upper two-thirds, uterine elevation out of the deep pelvis, nipple erection, areolar enlargement

Plateau

• Further increases in heart rate, respiratory rate, muscle tone

• Sex flush may develop (rash over the chest, neck, and face)

• Men: Increase in diameter and color of the glans penis, increase in testicular elevation and size of 50%-100% over baseline

• Women: Breast engorgement by up to 50% and clitoral shaft and glans retraction

• Lasts seconds to minutes, and is often described as a “general sense of well-being”

Orgasm

• Further increases in heart rate, respiratory rate, blood pressure

• Involuntary rhythmic contractions of the pelvic floor muscles

• Men: Only one orgasm per cycle

• Women: Can have multiple orgasms per cycle or can skip this phase altogether and go straight from plateau to resolution

Resolution

• Generalized perspiration in conjunction with gradual reversal of the above changes in heart rate, blood pressure, and respiratory rate

• Lasts 5-15 minutes, but the penis does not return to its normal size for 30-60 minutes after orgasm

Modified from Masters WH, Johnson VE: Human sexual response, Boston, 1980, Bantam Books.

There have been many critics of the Masters and Johnson sexual response model, primarily because it places too much emphasis on genital responses and does not acknowledge the role of central neurophysiologic control.^19,^136,^188,²³⁶ In the late 1970s, Kaplan devised a new model of sexual response with three phases: desire, excitement, and orgasm.¹¹⁹ In the Kaplan model, desire always precedes arousal, and is described as “the specific sensations that motivate the individual to initiate or become responsive to sexual stimulation.”^119,^125,¹⁸⁸ The Kaplan model, like that of Masters and Johnson, proposes that human sexual response is linear and basically invariant between men and women.¹²⁵

More recent research has furthered our understanding of human sexual response, particularly in regard to the ways in which the sexual response cycle is different in women and men. The Masters and Johnson, and Kaplan models ignore major components of women’s sexual satisfaction, such as the importance of trust, intimacy, affection, respect, and communication.¹⁹ Basson¹⁹^–²² proposed a new model for the female sexual response to address these gender differences in 2000 to 2001 (Figure 31-1).¹²⁵

FIGURE 31-1 Female sexual response cycle.

(Redrawn from Kingsberg SA, Janata JW. Female sexual disorders: assessment, diagnosis, and treatment, Urol Clin North Am 34:497-506, 2007.)

Basson’s circular model emphasizes that sexual response in women is much more complex than in men. In women a sexual encounter does not necessarily start from a place of spontaneous sexual drive or desire. Women often approach becoming intimate from a point of sexual neutrality, and the decision to become sexually engaged can result from numerous and varied factors, including a wish to emotionally connect with their partner.^19,¹²⁵ Sexual arousal and sexual satisfaction often do not occur solely through physical means such as clitoral stimulation and orgasm, but can also be dependent on intangible factors such as the ability to focus the mind on the present moment and a feeling of security or psychologic well-being.²⁵ The circular sexual response cycle might be repeated many times within the same sexual encounter.²⁵ Janssen et al.¹¹² have also proposed a circular model of human sexual response that is similar to that of Basson, but that might be more applicable to both genders.

Sexual Behavior and Aging

The frequency of sexual activity has been well documented to decline with age.¹¹⁶ Recent research has shown that the degree of decline is much less than was previously thought and that sexuality remains an important contributor to quality of life throughout the entire lifespan.^44,¹¹⁶ An important reason for the discrepancy is that older studies tended to quantify sexual activity only as intercourse, but more modern research looks at all aspects of sexuality.¹¹⁶ One study of men and women aged 80 to 102 years found that 63% of men and 30% of women continued to engage in sexual intercourse, whereas 83% of men and 64% of women participated in touching and caressing activities without intercourse, and 72% of men and 40% of women engaged in masturbation.⁴⁴

Many medical factors influence sexual activity in the elderly, including sexual dysfunction caused by medical illness, increasing frailty, and the side effects of medications. Postmenopausal women tend to experience vulvovaginal atrophy and vaginal dryness, which causes pain with vaginal penetration.¹¹⁸ Men have decreased testosterone with advancing age, which contributes to diminished sexual drive and also has physical effects that contribute to increased frailty.¹¹⁷ Psychosocial barriers to sexual activity in the elderly are numerous, including decreased partner availability, alterations in body image and change in self-perception, cognitive decline, and environmental issues such as the loss of privacy experienced in many residential settings.^79,¹¹⁷

Types of Sexual Dysfunction

Classification Systems

Sexual dysfunction is most frequently classified according to the Diagnostic and Statistical Manual, Fourth Edition, Text Revision (DSM-IV-TR).¹⁰ To qualify as a sexual dysfunction, a person’s sexual problem must cause “marked distress or interpersonal difficulty.” This distinction is important to remember for patients with disabilities, because they might experience altered sexual response but not have a sexual dysfunction in need of further workup or treatment.²¹⁹ In the same way that spasticity after stroke or phantom sensations after amputation are not always problems that need to be addressed by the physician, a patient’s sexual difficulties only need to be treated when the patient’s quality of life is adversely affected.

The DSM-IV-TR allows for three subtypes to be applied to all primary diagnoses to further clarify the nature of the sexual dysfunction. The first subtype describes the onset of the disorder—lifelong or acquired (which means it developed after a period of normal functioning). The second subtype is used to designate the context in which the dysfunction occurs—generalized or situational (meaning limited to certain types of stimulation, situations, or partners). The third subtype delineates the etiologic factors associated with the sexual dysfunction—the practitioner must decide whether the problem is due to psychologic factors alone, or due to a combination of psychologic factors and the pathologic effects of a general medical condition. If the sexual disorder is fully explained by a general medical condition or substance abuse, without psychogenic factors, then it is coded separately. The DSM-IV-TR sexual dysfunctions are summarized in Table 31-2.¹⁰ There has been recent scholarly debate about the clinical usefulness of the DSM-IV-TR system of classification.^13,^27,²⁸ It is based on the Masters and Johnson, and Kaplan linear models of human sexual response, and therefore often criticized as not being representative of the true nature of human sexual response, particularly for female sexual dysfunction.¹⁹ Another problem with the DSM-IV-TR criteria is that sexual disorders, particularly erectile dysfunction and dyspareunia, are typically diagnosed independent of etiology. Sexual disorders are difficult to fully classify according to criteria which mandate that the etiology is known before diagnosis.²⁷ In addition, research has shown that there is often a high degree of overlap or comorbidity among the sexual disorders, particularly in women, and the DSM-IV-TR classification system does not allow for these findings.^27,^135,^190,²⁰⁶

Table 31-2 Sexual Dysfunctions in the DSM-IV-TR

Sexual Desire Disorders
302.71	Hypoactive Sexual Desire Disorder
302.79	Sexual Aversion Disorder
Sexual Arousal Disorders
302.72	Female Sexual Arousal Disorder
302.72	Male Erectile Disorder
Orgasmic Disorders
302.73	Female Orgasmic Disorder
302.74	Male Orgasmic Disorder
302.75	Premature Ejaculation
Sexual Pain Disorders
302.76	Dyspareunia (not due to a general medical condition)
306.51	Vaginismus (not due to a general medical condition
Sexual Dysfunction Due to a General Medical Condition
625.8	Female Hypoactive Sexual Desire Disorder due to a general medical condition
608.89	Male Hypoactive Sexual Desire Disorder due to a general medical condition
607.84	Male Erectile Disorder due to a general medical condition
625.0	Female Dyspareunia due to a general medical condition
608.89	Male Dyspareunia due to a general medical condition
625.8	Other Female Sexual Dysfunction due to a general medical condition
608.89	Other Male Sexual Dysfunction due to a general medical condition
___.__	Substance-Induced Sexual Dysfunction (coding is substance-specific)
302.70	Sexual Dysfunction Not Otherwise Specified

From American Psychiatric Association: Diagnostic and statistical manual of mental disorders, fourth edition, text revision (DSM-IV-TR), Washington, DC 2000, American Psychiatric Association.

A number of international consensus conferences have been held to address these concerns.^26,^27,^140,¹⁴¹ Their guidelines follow the same general format as the DSV-IV-TR (primarily to retain consistency for research purposes), but they introduced updated definitions of the disorders. The DSM-V is set to be published in 2012, but until that time the reports of these consensus conferences contain the current best set of definitions of sexual dysfunction, and are summarized and expanded on below.¹¹

Male Sexual Dysfunction

The main focus of both clinical care and research for men with sexual dysfunction has traditionally been centered on performance problems, particularly erectile dysfunction and premature ejaculation. There has been a major paradigm shift in the past two decades away from the psychiatric understanding of most sexual disorders in men and toward a medicalization of male sexuality (particularly with the advent of proerection medications).^150,^156,¹⁹² Purely psychogenic male sexual disorders are much more underrepresented in the medical literature and are often misdiagnosed as erectile dysfunction by health practitioners.¹⁵⁷ Types of male sexual dysfunction include the following:

• Hypoactive sexual desire disorder (HSDD): Persistent or recurrent absence or deficit of sexual fantasies and desire for sexual activity, accounting for factors that affect sexual function, such as age and life context. HSDD has been reported in 0% to 15% of men, with one recent metaanalysis by Simons and Carey ²¹⁶ indicating a prevalence of 0% to 3% from community samples.^157,¹⁸⁷

• Sexual aversion disorder: Persistent or recurrent extreme aversion to, and avoidance of, all (or almost all) genital sexual contact with a sexual partner.

• Male erectile disorder (erectile dysfunction [ED]): Persistent or recurrent inability to attain, or to maintain until completion of the sexual activity, an adequate erection. The diagnosis is primarily based on the patient’s self-report, and ED must occur on a recurrent basis for a minimum of 3 months to establish the diagnosis, (unless there is a history of trauma or surgically induced ED).¹⁴¹ Prevalence estimates for ED vary greatly, from 0% to 5%, to 52%.^71,^205,²¹⁶ Results of the Massachusetts Male Aging Study in 1994 showed that 35% of men aged 40 to 70 years demonstrated moderate to severe ED, with another 25% exhibiting mild symptoms.⁷⁵ The 2006 National Health and Nutrition Examination Study was tailored to create a racially diverse sample population, and found ED in one of every five respondents older than 20 years.¹⁹⁹ ED is known to be associated with advanced age, cardiovascular disease, diabetes, dyslipidemia, smoking, obesity, and depression, so the prevalence of this disorder is predicted to grow in keeping with the prevalence of these conditions.²⁰⁵ ED was previously known as impotence, but the term has been phased out because of its pejorative implications and lack of precision.^167,²⁰⁵

• Premature ejaculation disorder (PE): Persistent or recurrent ejaculation with minimal sexual stimulation before, on, or shortly after penetration and before the person wishes it. Factors that affect duration of the excitement phase must be taken into account, such as age, novelty of the sexual partner or situation, and recent frequency of sexual activity. Recent consensus has determined that three other conditions must be met to diagnose PE: (1) ejaculatory latency of within 1 to 1.5 minutes of vaginal penetration; (2) lack of control over the ability to delay ejaculatory response; and (3) psychologic distress in the patient, the patient’s partner, or both.^141,^154,¹⁹³ PE is among the most common of the male sexual dysfunctions, with estimates ranging from 15% to 30% across all age cohorts.^135,^189,¹⁹³ About 30% of men with PE have concomitant ED, which typically results in early ejaculation without full erection.⁹⁷ PE is often caused by a combination of organic, psychogenic, and relationship-based causes.¹⁹³

• Male orgasmic disorder (MOD): Persistent or recurrent delay in, or absence of, orgasm after a normal sexual excitement phase during sexual activity, which is adequate in focus, intensity, and duration. MOD is usually further broken down into the following disorders: inhibited ejaculation (also known as delayed ejaculation), anejaculation, anorgasmia, retrograde ejaculation, and age-related penile hypoesthesia.^141,¹⁵³ MOD can originate through a variety of anatomic, neurogenic, and endocrine-related causes, as well as medication-related side effects and psychogenic etiologies.¹⁵³ The prevalence of MOD in the general population is thought to be low, from 0% to 9%.²¹⁶

• Dyspareunia: Recurrent or persistent genital pain associated with sexual intercourse. Dyspareunia in men is much less prevalent than in women, with estimates ranging from 0.2% to 8%.²¹⁶ In gay men, the prevalence has been estimated at 3% (insertive) and 16% (receptive).¹⁹¹

• Priapism: An unwanted erection not associated with sexual desire or sexual stimulation and lasting for more than four hours. There are three different types of priapism: (1) low-flow or ischemic priapism, (2) high-flow or well-oxygenated priapism, and (3) recurrent or stuttering priapism.¹⁴¹ Low-flow priapism is the most common type. It is an example of compartment syndrome and can lead to necrosis of the cavernous muscle if not treated urgently. High-flow priapism is less prevalent and can be congenital, idiopathic, or occur after surgical treatment or pelvic trauma. Stuttering priapism occurs most frequently in sickle cell disease and is usually high flow. Priapism is a relatively rare condition and is usually associated with the use of drugs and with vascular dysfunction.¹³⁹

• Peyronie’s disease: An acquired disorder of the tunica albuginea characterized by the formation of a plaque of fibrous tissue and often accompanied by penile pain and deformity on erection. There can be excessive penile curvature that causes difficulty with penetration and impairment in erectile capacity.¹⁴¹ Peyronie’s disease is typically related to trauma to the penis. The incidence has been reported to be 1% in the general population and increases with age.¹¹⁴ It is estimated that Peyronie’s disease will develop in 5% of men older than 50 years.²²⁶

Female Sexual Dysfunction

Female sexual dysfunction is very common, with a reported prevalence of 40% to 50% in multiple population-based studies.^13,¹³⁵ Sexual dysfunction in women has become a focus of renewed research interest in the past decade, in part based on the new understanding of the female sexual response cycle proposed by Basson,¹⁹ and the implications of that understanding toward diagnosis and treatment.¹⁵⁰ In contrast to sexual dysfunction in men, the psychologic aspect of women’s sexual functioning typically receives far more attention than organic etiologies of dysfunction. This discrepancy is partially because of institutional bias, but it is also based on a growing body of data suggesting that psychologic factors correlate more strongly with sexual dysfunction in women than do medical problems.^26,¹³⁵ It is especially important to remember that personal distress is necessary to make a diagnosis of sexual dysfunction when dealing with female patients. Up to 50% of women who report a problem with sexual functioning do not have any associated personal distress, and so they cannot be classified as having a sexual dysfunction.²⁰⁷ Types of female sexual dysfunction include the following:

• HSDD (also known as women’s sexual interest/desire disorder): Absent or diminished feelings of sexual interest or desire, absent sexual thoughts or fantasies, and a lack of responsive desire. Motivations (defined as reasons or incentives) for attempting to have sexual arousal are scarce or absent. The lack of interest must be beyond what would be considered normal for the woman’s age and relationship duration, and must be a frequent and persistent problem not related to changes in life situation or relationship dynamics.^26,²⁰⁷ The lack of responsive desire is the key to diagnosis, because many normal women do not have spontaneous sexual thinking, fantasizing, or desire ahead of sexual activity.²³ HSDD in women has traditionally been linked with menopause, but recent population studies have not found a strong association with menopause. It is unclear whether menopausal status or even increasing age are directly related to the development of HSDD.^103,^125,²⁰⁷ Prevalence estimates vary widely in population-based studies, and are typically quoted at 24% to 43%. Segraves and Woodard,²⁰⁷ however, estimate that prevalence is likely much lower (closer to 5.4% to 13.6%) if strict criteria for the diagnosis of HSDD are applied.

• Sexual aversion disorder: Persistent or recurrent phobic aversion and avoidance of sexual contact. It is often accompanied by physiologic responses to attempted sexual relations, such as panic attacks, nausea, revulsion, and shortness of breath.¹²⁵ A history of sexual trauma or physical or sexual abuse usually underlies the development of the disorder.⁸ The prevalence is unknown, and the disorder is considered rare by some and widespread by others.^60,⁸⁰

• Female sexual arousal disorder: Persistent or recurrent inability to attain or to maintain until completion of the sexual activity, sufficient sexual excitement. This can be expressed as a lack of subjective excitement, or as a lack of adequate genital (lubrication-swelling) or other somatic response.²⁷ Three subtypes to this diagnosis have recently been proposed: (1) subjective sexual arousal disorder (with maintained vaginal lubrication but lack of subjective feelings of sexual excitement), (2) combined genital and subjective arousal disorder (no subjective or physiologic arousal), and (3) genital sexual arousal disorder (absent genital lubrication-swelling response with the presence of subjective sexual excitement from nongenital stimuli).^26,¹²⁵ The prevalence is estimated to be 6% to 21%.²¹⁶

• Persistent sexual arousal disorder: Spontaneous intrusive and unwanted genital arousal (such as tingling, throbbing, or pulsating) in the absence of sexual interest and desire. Any awareness of subjective arousal is typically but not invariably unpleasant. The arousal is usually unrelieved by orgasm and persists for hours to days.²⁶

• Female orgasmic disorder: Persistent or recurrent lack of orgasm, markedly diminished intensity of orgasmic sensations, or marked delay of orgasm from any kind of stimulation despite the self-report of high sexual arousal or excitement.²⁶ Orgasmic disorder in women is often difficult to distinguish from arousal disorder without a careful history, because women with decreased arousal will also not be able to achieve orgasm.¹²⁵ Many women are situationally orgasmic, in that they can reliably achieve orgasm with some forms of stimulation but not others. Intercourse alone is not a reliable way for many women to achieve orgasm.¹²⁵ The prevalence of female orgasmic disorder was estimated at 24% in the National Health and Social Life Survey.¹³⁵ Other estimates range from 4% to 42% based on research setting and methodology.²¹⁶

• Vaginismus: The persistent or recurrent difficulties of the woman to allow vaginal entry of a penis, a finger, and/or any object, despite the woman’s expressed wish to do so. There is often phobic avoidance of penetration and the anticipation or fear of pain in addition to the possible experience of pain, along with variable involuntary pelvic muscle contraction or spasm.²⁶ Structural or physical abnormalities must be ruled out or addressed. Vaginismus was previously defined as persistent spasm of the outer third of the vaginal musculature that interferes with vaginal penetration, and it is often classified as a sexual pain disorder. Recent research and consensus opinion dispute the classic definition because muscle spasm and even pain are not always present.^10,^26,^125,¹⁸² Prevalence rates are reported at 1% to 6%.¹⁴⁰

• Dyspareunia: Persistent or recurrent pain with attempted or complete vaginal entry, penile vaginal intercourse, or both.²⁶ Dyspareunia was previously thought to be primarily of psychogenic origin, but it is now known that biologic factors often contribute to the presentation.¹²⁵ Some even characterize dyspareunia as a pain disorder that interferes with sexuality instead of a sexual disorder characterized by pain.^37,¹²⁵ The differential diagnosis of dyspareunia in women includes vulvovaginal atrophy, postmenopausal vaginal dryness, and pelvic floor myofascial pain or dysfunction. Other common causes of dyspareunia include vulvodynia (vulvar pain without visible signs of pathologic condition and with no known etiologic diagnosis), vestibulodynia (a type of vulvodynia localized only to the vulvar vestibule), and vulval vestibulitis syndrome (vestibulodynia with associated inflammatory changes visible on physical examination).^29,^91,¹²⁵ Urethral disorders, cystitis, bladder pain syndrome (formerly known as chronic interstitial cystitis), anatomic variations, pelvic adhesions, infections, endometriosis, inflammatory bowel disease, abdominal wall pain, cancer, late effects of pelvic radiation, vulvovaginal dermatologic diseases (such as lichen sclerosis or lichen planus), and pelvic congestion syndrome can also cause chronic dyspareunia.^29,^125,²⁴¹ Dyspareunia prevalence estimates range from 3% to 18% in the general population, 3% to 46% in a primary care setting, and 9% to 21% in postmenopausal women.²¹⁶

• Noncoital sexual pain disorder: Recurrent or persistent genital pain induced by noncoital sexual stimulation. Differential diagnosis includes inflammatory, dermatologic, and anatomic conditions as well as trauma.¹³

Sexual Dysfunction in Disability and Chronic Disease

The development of sexual dysfunction after the onset of disability is usually related to a myriad of diverse etiologic factors that can grouped into five different categories: primary physical changes, secondary physical limitations, psychosocial contributions, the effect of comorbid conditions, and medication-related factors.

Primary physical changes derive from the disease pathophysiology and directly affect sexual response. These primary physical changes could include altered genital sensation, decreased vaginal lubrication, ED, or anorgasmia. Secondary physical limitations also play a significant role in the development of sexual difficulties after disability. These are indirect effects of the disease process that do not affect genital function or sexual response, but that make sexual activity unpleasant or challenging. Examples of secondary physical limitations include fatigue, pain, weakness, spasticity, contractures, ataxia, bowel and bladder dysfunction, and cognitive impairment. The psychosocial contribution to the development of sexual dysfunction includes psychologic, emotional, relational, situational, social, and cultural factors. People with disabilities often have difficulty adjusting to their new life circumstances. They can have poor self-esteem and body image, fear of isolation and abandonment, anger, shame, guilt, strained relationships with loved ones, anxiety, and depression. All of these issues can affect sexual functioning. The fourth category to consider is the effect of comorbid conditions, particularly diabetes, cardiovascular disease, and depression, which can cause sexual dysfunction independent of the pathology of the primary disability. Finally, many medications commonly prescribed for people with disabilities can lead to the development of sexual dysfunction (as detailed later in this chapter).

It is important for the practitioner to consider factors from all five categories when diagnosing and treating a disabled patient with sexual dysfunction. Disability-specific sexual dysfunctions are discussed below.

Spinal Cord Injury

In contrast to many of the other disabilities discussed in this chapter, sexual dysfunction in patients with spinal cord injury (SCI) has been well studied in both genders (see Chapter 55). The type of sexual dysfunction the patient will ultimately experience depends in large part on the spinal cord level and the degree of completeness of the injury.¹⁶² Multiple studies have shown that the frequency of sexual activity and the level of sexual satisfaction decrease in both men and women after sustaining an SCI.^5,^53,²²¹

Upper motor neuron (UMN) SCI allows for reflexogenic erection to occur in men, because the parasympathetic sacral reflex arc is intact. Psychogenic erection, however, is usually not possible unless the injury is incomplete. Ejaculation is difficult for these patients because it is sympathetically mediated from T11–L2. Lower motor neuron (LMN) SCI has preserved integrity of the thoracolumbar sympathetic outflow tract, and psychogenic erections and ejaculation are theoretically more likely to be intact, but reflexogenic erections are not.

Bors and Comarr ⁴¹ conducted a pivotal study in 1960 detailing the prevalence of erectile and orgasmic dysfunction in 529 men with SCI. They found that in men with complete UMN lesions, 93% of patients were able to achieve reflexogenic erections, and none were able to attain psychogenic erections. Anterograde ejaculation in complete UMN SCI was seen in 4% of patients. Men with incomplete UMN SCI achieved erections 99% of the time, with 80% of men having only reflexogenic erections and 19% having combined reflex and psychogenic erections. Ejaculation was possible in 32% of patients with incomplete UMN SCI, with 72% of those occurring after reflexogenic erection and 26% occurring after psychogenic erection. Complete LMN lesions showed a very different picture, with 26% of patients able to achieve psychogenic erections and none attaining reflexogenic ones. Ejaculation was possible in 18% of these men. Incomplete LMN lesions fared far better, with 90% of men retaining the ability to achieve erection and 70% the ability to ejaculate. The results of the Bors and Comarr study are summarized in Figures 31-2 and 31-3.

FIGURE 31-2 Percentage of men with spinal cord injury able to achieve erection.

(Data from Bors E, Comarr AE: Neurological disturbances of sexual function with special reference to 529 patients with spinal cord injury, Urol Surv 110:191-221, 1960.)

FIGURE 31-3 Percentage of men with spinal cord injury able to achieve anterograde ejaculation.

(Data from Bors E, Comarr AE: Neurological disturbances of sexual function with special reference to 529 patients with spinal cord injury, Urol Surv 110:191-221, 1960.)

Orgasmic ability has been shown to be preserved in 38% to 50% of men with complete UMN SCI, 78% to 84% of men with incomplete UMN injury, and 0% of men with complete LMN injury.^5,^6,^178,²¹⁸ It should be noted, however, that most studies of men have focused on the ability to ejaculate instead of the ability to have an orgasm, which have more recently been noted to be separate occurrences.⁶ Some men are also occasionally able to achieve orgasm without anterograde ejaculation, possibly indicating either anejaculation or retrograde ejaculation into the bladder.²¹⁸

Women with SCI have more recently been shown to have sexual responses that are similar to those of men, with arousal and vaginal lubrication as the female correlate to penile erection.^222,²²³ In women with complete UMN injuries, reflexogenic but not psychogenic lubrication is preserved.²²³ Sensation to light touch and pinprick in the T11–L2 dermatomes was found to be predictive of the ability for psychogenic vaginal lubrication (which is thought to be sympathetically mediated).²²² From 44% to 54% of women with SCI have been shown to be able to achieve orgasm, although orgasm is much less likely in women with LMN injuries affecting the S3–S5 segments.^53,^110,^221,²²²

Fertility in men with SCI is impaired, in part because of a decreased ability to ejaculate.¹⁸¹ Semen quality has also been found to be poor in men with SCI, with decreased sperm motility, decreased mitochondrial activity, and increased sperm DNA fragmentation.¹⁸³ Reasons for altered semen quality have been postulated to include seminal fluid stasis, testicular hyperthermia, recurrent genitourinary tract infections, and hormonal dysfunction.¹⁸³ Fertility in women with SCI is preserved once menstruation resumes, on average about 5 months postinjury.¹⁵

Stroke

Stroke is the world’s second leading cause of death and the leading cause of adult disability.⁵⁴ Sexual dysfunction is a common finding after stroke in both men and women (see Chapter 50). The most common findings for men are erectile and ejaculatory dysfunction (in 40% to 50%) and decreased sexual drive.^115,^127,^145,²³³ Women tend to experience decreased sexual drive, decreased vaginal lubrication (in approximately 50%), decreased orgasm (in about 20% to 30%), and decreased overall sexual satisfaction.^123,^127,^145,²³³ The prevalence of decreased sexual drive has been reported to be between about 25% and 60% in both genders after stroke.^123,¹²⁷ Stroke also leads to significantly decreased frequency of sexual activity in both genders, and in one study, approximately 50% of stroke survivors reported no sexual activity whatsoever by 1 year poststroke.^86,^127,²³³

The physical effects of stroke that contribute to sexual dysfunction include hemiparesis with its effect on body positioning and movement, hemineglect, hemianopsia, neurogenic bowel and bladder, and spasticity.^163,¹⁸¹ Not much is known about the functional neuroanatomy of sexual behavior and control, but some studies have indicated that the right cerebral hemisphere might play a more important role in sexual functioning than the left side.^57,^83,¹¹⁵ Many studies have suggested that sexual dysfunction after stroke is related to the presence of medical comorbidities (cardiac disease, diabetes, hypercholesterolemia, depression), medications, and psychosocial factors (inability to discuss sexuality with the partner, unwillingness for sexual activity, fear of another stroke, sexuality being unimportant) rather than the direct effect of stroke.^∗

Traumatic Brain Injury

The prevalence of sexual dysfunction after traumatic brain injury has been reported at 4% to 71%, a wide range that likely represents the limited number of quality studies and the varied types and severities of injury that are possible ²⁰¹ (see Chapter 49). Types of sexual dysfunction reported have been similar to those seen in patients with stroke, including reduced sexual desire and frequency of sexual activity in both genders, ED and ejaculatory dysfunction in men, and dyspareunia, anorgasmia, and reduced lubrication in women.^104,^128,^181,²⁰¹ In addition, brain injury can cause hypersexual behavior such as excessive masturbation. This can occur in particular with injury to the limbic system or prefrontal regions, which can cause disinhibition; or to bilateral temporal poles, which produces the Klüver-Bucy syndrome of hypersexuality and hyperorality.^46,^137,²¹⁷ The prevalence and type of sexual dysfunction can be associated with both the global amount of brain tissue destroyed and the focality of injuries.¹⁸¹ Sexual dysfunction does not seem to correlate with the amount of cognitive impairment, the length of posttraumatic amnesia, or the burden of neurologic disability.^40,^181,²⁰¹ Medications, particularly anticonvulsants, can greatly contribute to the sexual dysfunction witnessed after brain injury.⁸⁹ Psychosocial factors seems to play a major role in sexual functioning after brain injury, with the presence of depression being the most sensitive indicator for sexual dysfunction.¹⁰⁴ Other important psychologic factors include perceived health status and quality of life, low self-esteem, anxiety, and perceived decline in personal sex appeal.^104,¹²⁹

Multiple Sclerosis

Multiple sclerosis (MS)-induced sexual dysfunction is present in 40% to 80% of women and 50% to 90% of men ⁶⁶ (see Chapter 52). Women tend to have decreased sexual desire, anorgasmia, decreased vaginal lubrication, and increased spasticity with sexual activity.^61,^107,¹⁸¹ Many of these symptoms are thought to be related to the decreased genital sensitivity experienced by 62% of women with advanced MS.¹⁰⁷ Men with MS have ED, ejaculatory dysfunction (premature, delayed, or absent), orgasmic dysfunction, decreased genital sensation, and decreased sexual drive.^61,¹⁸¹

The sexual disorders have historically been attributed directly to the location and duration of the spinal cord or brain lesion, but more recent research tends to describe a multitude of other factors that also contribute to the development of sexual dysfunction in MS. These include secondary physical limitations, psychologic factors, and the side effects of MS medications.^134,²²⁷ In one study, sexual dysfunction in men with MS was found to be positively correlated with lower-limb disability and bladder dysfunction, but in women the sexual disorders were most strongly correlated with fatigue.⁸⁰ Secondary physical limitations include fatigue, bowel and bladder dysfunction, muscle weakness, spasticity, poor coordination, inability to properly position oneself for an enjoyable sexual encounter, numbness, paresthesias, pain, and cognitive impairment.^134,²²⁷ Psychosocial factors that significantly contribute to MS-related sexual dysfunction include poor self-image, poor self-esteem, fear of isolation and abandonment, shame, dependency on one’s partner to provide for one’s basic needs, and depression.^204,²²⁷

Other Neurologic Disorders

Parkinson’s disease (PD) is often associated with low testosterone levels, and therefore decreased sexual drive ¹⁶³ (see Chapter 51). In one study of young men with PD (ages 36 to 56 years), up to 40% had low sexual desire. Men with PD also can experience ED and PE.¹⁸¹ Treatment with dopamine and dopamine agonist medications, on the other hand, has been documented to cause hypersexual behavior, which often accompanies mania.²³⁸ Hypersexuality has also been described with deep brain stimulation of the subthalamic nucleus.¹⁸⁵

Patients with epilepsy can exhibit involuntary sexual gestures, erotic feelings, and orgasm during seizure activity.¹⁸¹ These dysfunctions are most commonly seen with complex partial seizures arising from the temporolimbic or frontolimbic circuitry.¹⁸¹ Ictal genital automatisms (such as self-fondling or pelvic thrusting) were reported in one study to occur in 11% of patients observed with video electroencephalographic monitoring.⁶⁹ Ictal orgasm has been reported much more frequently in women than in men.¹⁸¹

Peripheral neuropathy can cause sexual dysfunction, particularly when the etiology is diabetes, amyloid, and some of the inherited neuropathies with urogenital symptoms as prominent early features.¹⁸¹ Guillain-Barré syndrome has been linked to ED when there is residual neurologic deficit or disability after recovery.⁵⁰

Chronic Pain

The reasons for sexual dysfunction in patients with chronic pain are multifactorial, often related to physiologic, pharmacologic, and psychologic factors ¹⁷³ (see Chapter 42). In one study, 73% of patients with chronic pain had pain-related difficulty with sexual activity. The reasons for this included decreased arousal, positioning issues, exacerbations of pain, low confidence, performance worries, and relationship issues.⁹ In another study, sexual problems were reported in 46% of patients with low back pain.⁷¹ Women with low back pain have been shown to have decreased frequency of sexual activity, more pain during sexual intercourse, and decreased sexual desire compared with men with low back pain or patients of either gender with neck pain.¹⁴³ Sexual dysfunction in patients with chronic pain has been correlated most strongly with the presence of depression, poor coping skills, and shorter pain duration.¹³⁰ Many of the medications used to treat chronic pain (including opioids, antidepressants, and anticonvulsants) can independently contribute to sexual dysfunction.²³⁵ Chronic pelvic pain in women, which frequently causes dyspareunia and other sexual dysfunctions, can be related to childhood physical abuse, sexual abuse, and emotional neglect. It can also have an organic etiology (as detailed previously in this chapter).¹³³

Rheumatologic Disease

Osteoarthritis affects sexual function primarily through associated joint pain, stiffness, and fatigue, and the hip joint is the most often implicated in leading to sexual difficulties ^38,^60,¹⁶³ (see Chapter 36). Total hip replacement often significantly improves sexual functioning; in one study, 65% of patients found relief from sexual difficulties after the surgery.²³¹ It is important to instruct patients in proper positioning after joint replacement to reduce the risk of dislocation, and many surgeons instruct patients to refrain from sexual intercourse for 1 to 2 months after hip replacement for this reason.²²⁰

Rheumatoid arthritis (RA), like osteoarthritis, can cause problems in sexual functioning through joint pain, stiffness, and fatigue.¹⁶⁶ RA in men has also been shown to be associated with decreased sexual desire and ED during periods of active inflammation.⁹³ One recent study of women with RA identified 62% with difficulties in sexual performance caused by joint pain and stiffness, and 92% with diminished sexual desire or satisfaction.² Difficulties in sexual performance were related to the overall level of disability and hip involvement, whereas decreased sexual desire and satisfaction were correlated more with perceived pain, age, and depression.

The effect of fibromyalgia on sexual dysfunction in women has been looked at in one recent study,¹⁷² which found that 97% of women with fibromyalgia reported sexual dysfunction, including decreased sexual desire, arousal, and orgasm. The degree of sexual difficulty was found to be very strongly correlated with the degree of depression. Other correlates included level of anxiety, age, pain intensity, and marital and work status.

Amputation

Patients with limb amputation usually have preserved sexual genital functioning (unless there is a comorbid condition such as diabetes or cardiac disease, or the side effects of their medications play a significant detrimental role)¹⁰⁸ (see Chapters 12 and 13). But their sexual life can be significantly affected by a variety of factors associated with their amputation, including depression, poor self-esteem and body image, phantom sensations and pain, problems with balance and movement, and difficulties with body positioning during sexual activity.²¹² Preservation of the knee joint can be helpful for maintaining balance during sexual intercourse, although transfemoral amputees can use pillows to aid in positioning.⁴⁸ Upper limb amputees would benefit from side-lying or supine positioning to allow for free movement of both the intact arm and the residual limb.²²⁰