Human Sexual Response

The classic model of human sexual response was formulated by Masters and Johnson 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 ( Box 22-1 ). 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 Johnson also noted that women could become “stalled” at the plateau phase and then pass straight to resolution without achieving orgasm.

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. In the late 1970s, Kaplan devised a new model of sexual response with three phases: desire, excitement, and orgasm. 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.” The Kaplan model, like that of Masters and Johnson, proposes that human sexual response is linear and basically invariant between men and women.

More recent research has furthered our understanding of human sexual response, particularly 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. Basson proposed a new model for the female sexual response to address these gender differences ( Figure 22-1 ).

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 that 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. Sexual arousal and sexual satisfaction often do not occur solely through physical means, such as clitoral stimulation and orgasm, but may also be dependent on intangible factors, such as the ability to focus the mind on the present moment and a feeling of security or psychological well-being. The circular sexual response cycle may be repeated many times within the same sexual encounter. Janssen et al. have also proposed a circular model of human sexual response, which is similar to that of Basson, which might be more applicable to both genders.

Sexual Behavior and Aging

The frequency of sexual activity has been well documented to decline with age. 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 life span. 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. The 2009 National Survey of Sexual Health and Behavior found that although sexual activity declined with age, in participants aged 70 years or older, 43% of men and 22% of women reported vaginal intercourse in the year before the study. Solo masturbation was reported in 46% of men and 33% of women in this age group.

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 cause pain with vaginal penetration. Men have decreased testosterone with advancing age, which contributes to diminished sexual drive and also has physical effects that contribute to increased frailty. 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.

Classification

Sexual dysfunction is most frequently classified according to the Diagnostic and Statistical Manual, fifth edition (DSM-5), which was published in 2013. To qualify as a sexual dysfunction, a person’s sexual problem must cause “significant distress.” 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. 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-5 stipulates that sexual dysfunction diagnoses require a minimum of 6 months’ duration and that symptoms must be present 75% to 100% of the time (with the exception of medication-induced sexual dysfunction disorders). The DSM-5 also allows for two subtypes to be applied to all primary diagnoses to further clarify the nature of the 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 patient’s sexual dysfunction should not be able to be better explained by a “nonsexual mental disorder, a consequence of severe relationship distress (e.g., partner violence), or other significant stressors.” The DSM-5 criteria highlight the importance of separate classification systems for men and women, and abandons the Masters and Johnson linear sexual response model for both sexes. The DSM-5 sexual dysfunctions are summarized in Table 22-1 . In addition to the DSM-5, there have been a number of international consensus conferences which have helped to further define and classify sexual dysfunctions.

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 2 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). Purely psychogenic male sexual disorders are much more underrepresented in the medical literature and are often misdiagnosed as erectile dysfunction by health physicians. Types of male sexual dysfunction include the following:

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  Male Hypoactive Sexual Desire Disorder: 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. Hypoactive sexual desire disorder has been reported in 0% to 15% of men, with a metaanalysis by Simons and Carey indicating a prevalence of 0% to 3% from community samples.

  
  
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  Erectile Disorder/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 to establish the diagnosis (unless there is a history of trauma or surgically induced ED). Prevalence estimates for ED vary greatly, from 0% to 5%, to 52%. 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. The 2006 National Health and Nutrition Examination Study was tailored to create a racially diverse sample population, and found ED in one out of every five respondents over the age of 20 years. 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. ED was previously known as impotence, but the term has been phased out because of its pejorative implications and lack of precision.

  
  
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  Premature (Early) Ejaculation Disorder: Persistent or recurrent ejaculation before or within approximately 1 minute of intravaginal penetration and before the person wishes it. This contrasts the average intravaginal ejaculation latency time (IELT) of 5.4 minutes in multinational populations. 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. Consensus opinions also recognize that psychological distress in the patient and/or in the patient’s partner is a critical diagnostic component. Prevalence data for premature ejaculation are often limited to self-report, with estimates of up to 30% across all age cohorts. However, when the IELT time parameter is applied to diagnostic criteria, prevalence drops to 1% to 3%. Approximately 30% of men with premature ejaculation have concomitant ED, which typically results in early ejaculation without full erection. Premature ejaculation is often caused by a combination of organic, psychogenic, and relationship-based causes. More recently, neurobiologic and genetic variations have been proposed as contributing factors in premature ejaculation.

  
  
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  Delayed Ejaculation: Persistent or recurrent unwanted delay in, or absence of, ejaculation following a normal sexual excitement phase during sexual activity, which is adequate in focus, intensity, and duration. This condition was formerly termed male orgasmic disorder. Delayed ejaculation can originate through a variety of anatomic, neurogenic, and endocrine-related causes, as well as medication-related side effects and psychogenic etiologies. As the least common sexual complaint among men, the prevalence of delayed ejaculation in the general population is thought to be in the range of 0% to 9%, and is more likely to affect partnered versus masturbatory ejaculatory responses.

  
  
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  Dyspareunia: Recurrent or persistent genital pain associated with sexual intercourse. Male dyspareunia was eliminated as a separate entity in the DSM-5 (compared with previous editions of the DSM). This change was apparently made because dyspareunia in men is much less prevalent than in women; however, estimates do range from 0.2% to 8%. In gay men, the prevalence has been estimated at 3% (insertive) and 16% (receptive).

Female Sexual Dysfunction

Female sexual dysfunction is very common, with a reported prevalence of 40% to 50% in multiple population-based studies. Sexual dysfunction in women has become a focus of renewed research interest in the past 10 to 15 years, in part based upon the new understanding of the female sexual response cycle proposed by Basson and the implications of that understanding toward diagnosis and treatment. In contrast to sexual dysfunction in men, the psychological 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 psychological factors correlate more strongly with sexual dysfunction in women than do medical problems. 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 thus they cannot be classified as having a sexual dysfunction. Types of female sexual dysfunction include the following:

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  Female Sexual Interest/Arousal Disorder: With updated DSM-5 criteria, female sexual interest/arousal disorder is a convergence of the female desire and arousal disorders formerly termed female hypoactive sexual desire disorder and female sexual arousal disorder in DSM-IV-TR. For diagnosis, at least three of the following six criteria must be absent or reduced: (1) interest in sexual activity, (2) sexual/erotic thoughts or fantasies, (3) initiation of sexual activity or receptiveness to a partner’s initiation attempts, (4) sexual excitement/pleasure during sexual encounters, (5) sexual interest/arousal response to internal/external sexual/erotic cues, and (6) genital/nongenital sexual activity sensations during almost all or all sexual encounters. Owing to the recent classification of female sexual interest/arousal disorder as a unique disorder, the prevalence is currently unknown. Prevalence data for the previous DSM-IV-TR disorders of female hypoactive sexual desire disorder and female sexual arousal disorder have been well established:

  
  
  
  
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    Female hypoactive sexual desire disorder was previously defined as absent or diminished feelings of sexual interest or desire, absent sexual thoughts or fantasies, and a lack of responsive desire . Lack of interest was described as being beyond what would be considered normal for the woman’s age and relationship duration, and must have been a frequent and persistent problem not related to changes in life situation or relationship dynamics. The lack of responsive desire was the key to diagnosis, because many normal women do not have spontaneous sexual thinking, fantasizing, or desire ahead of sexual activity. Despite traditional notions, female hypoactive sexual desire disorder has not been clearly linked to menopause or advancing age. Prevalence estimates in population-based studies have been typically quoted at 24% to 43%, but may be much lower when strict diagnostic criteria are applied (closer to 5.4% to 13.6%).

    
    
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    Female sexual arousal disorder was previously defined as persistent or recurrent inability to attain, or to maintain until completion of the sexual activity, sufficient sexual excitement, which may be expressed as a lack of subjective excitement, or as a lack of adequate genital (lubrication-swelling) or other somatic response. The prevalence has been estimated to be 6% to 21%.

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

  
  
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  Genito-Pelvic Pain/Penetration Disorder: defined by persistent or recurrent difficulties with vaginal penetration, genito-pelvic pain during vaginal intercourse or other penetration attempts, fear or anxiety of genito-pelvic pain or vaginal penetration, and/or increased pelvic floor tension during attempted vaginal penetration. This disorder encompasses the former DSM-IV-TR disorders of dyspareunia (persistent or recurrent pain with attempted or complete vaginal entry and/or penile vaginal intercourse) and 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). Vaginismus was originally defined as persistent spasm of the outer third of the vaginal musculature, which interferes with vaginal penetration. More recent research and consensus opinion dispute the classic definition because muscle spasm and even pain are not always present. Prevalence rates for vaginismus have been reported at 1% to 6%. Vaginismus is one of many potential causes of dyspareunia. Dyspareunia was previously thought to be primarily of psychogenic origin, but it is now known that biologic factors often contribute to the presentation. Some even characterize dyspareunia as a pain disorder that interferes with sexuality instead of a sexual disorder characterized by pain. The differential diagnosis of dyspareunia in women includes vulvovaginal atrophy, postmenopausal vaginal dryness, pelvic floor myofascial pain or dysfunction, vulvodynia (vulvar pain without visible signs of pathology and with no known etiologic diagnosis), and vestibulodynia/vulvar vestibulitis syndrome (a type of vulvodynia localized only to the vulvar vestibule, which may or may not have associated inflammatory changes visible on physical examination). 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. 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.

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. The type of sexual dysfunction the patient will ultimately experience depends in large part upon the spinal cord level and the degree of completeness of the injury. Multiple studies have shown that the frequency of sexual activity and the level of sexual satisfaction decreases in both men and women after sustaining an SCI.

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 thus psychogenic erections and ejaculation are theoretically more likely to be intact but reflexogenic erections are not.

Bors and Comarr 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 erection 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% retaining the ability to achieve erection and 70% the ability to ejaculate. The results of the Bors and Comarr study are summarized in Figures 22-2 and 22-3 .

Percentage of men with spinal cord injury able to achieve erection. LMN, Lower motor neuron; UMN, upper motor neuron.

(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.)

Percentage of men with spinal cord injury able to achieve anterograde ejaculation. LMN, Lower motor neuron; UMN, upper motor neuron.

(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. It should be noted, however, that a majority of studies on men have focused on ability to ejaculate instead of ability to have an orgasm, which have more recently been noted to be separate occurrences. Some men are also occasionally able to achieve orgasm without anterograde ejaculation, possibly indicating either anejaculation or retrograde ejaculation into the bladder.

Women with SCI have been shown to have similar sexual responses to men, with arousal and vaginal lubrication as the female correlate to penile erection. In women with complete UMN injuries, reflexogenic but not psychogenic lubrication is preserved. 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. 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.

Fertility in men with SCI is impaired, in part because of a decreased ability to ejaculate. 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. Reasons for altered semen quality have been postulated to include seminal fluid stasis, testicular hyperthermia, recurrent genitourinary tract infections, and hormonal dysfunction. After initial postinjury decline, semen quality appears to plateau in the chronic postinjury period. Fertility in women with SCI is preserved once menstruation resumes, on average about 5 months postinjury. Family planning counseling should include these post-SCI fertility considerations.

Stroke

Stroke is the world’s second leading cause of death and the leading cause of adult disability. Sexual dysfunction is a common finding after stroke in both men and women. The most common findings for men are erectile and ejaculatory dysfunction (in 40% to 50%) and decreased sexual drive. Women tend to experience decreased sexual drive, decreased vaginal lubrication (in approximately 50%), decreased orgasm (in approximately 20% to 30%), and decreased overall sexual satisfaction. Prevalence of decreased sexual drive has been reported to be between approximately 25% to 50% in both genders after stroke, with similar effects in spouses. 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.

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. Not much is known about the functional neuroanatomy of sexual behavior and control, but some studies have indicated that the right cerebral hemisphere may play a more important role in sexual functioning than the left side. Many studies have suggested that sexual dysfunction following 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. *

* References .

Traumatic Brain Injury

The prevalence of sexual dysfunction after traumatic brain injury (TBI) has been reported at 4% to 71%, a wide range that is likely to represent the limited number of quality studies and the varied types and severities of injury that are possible. In a recent TBI model systems multicenter study of post-TBI community-dwelling individuals, 20% met criteria for sexual dysfunction. Greater impairments were correlated with female gender, older age, higher TBI severity, and decreased social participation. Although sexual dysfunction prevalence and type may be associated with both global and focal brain tissue injury, previous studies have not shown a consistent relationship to injury severity and sexual dysfunction. Types of sexual dysfunction reported have been similar to those seen in stroke patients, 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. 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. This can be treated with anticonvulsants, such as Depakote, but it is important to remember that such medications can also greatly contribute to the sexual dysfunction witnessed after brain injury. 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. Other important psychological factors include perceived health status and quality of life, low self-esteem, anxiety, and perceived decline in personal sex appeal.

Multiple Sclerosis

Multiple sclerosis (MS)-induced sexual dysfunction is present in 40% to 80% of women and 50% to 90% of men. Historically, the sexual disorders have 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.

In MS, sexual dysfunction is now conceptualized into three levels of dysfunction. Primary sexual dysfunction relates to neurologic impairments in libido, lubrication, and orgasm. Secondary sexual dysfunction includes the effects of fatigue and physical limitations on sexual expression. Physical limitations may include bowel and bladder dysfunction, weakness, incoordination, positioning and body control during sexual encounters, numbness, paresthesias, pain, and cognitive impairment. Tertiary sexual dysfunction reflects the psychological, emotional, social, and cultural implications of MS on sexual function. Psychosocial factors contributing to tertiary 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. Additionally, side effects of medication management may contribute to sexual dysfunction.

Women with MS tend to have decreased sexual desire, anorgasmia, decreased vaginal lubrication, and increased spasticity with sexual activity. Many of these symptoms are thought to be related to the decreased genital sensitivity experienced by 62% of women with advanced MS. Men with MS have ED, ejaculatory dysfunction (premature, delayed, or absent), orgasmic dysfunction, decreased genital sensation, and decreased sexual drive. In one study, sexual dysfunction in men with MS was found to be correlated with lower-limb disability and bladder dysfunction, whereas in women, sexual disorders were most strongly correlated with fatigue. Women report more symptoms of sexual dysfunction, whereas men report more dissatisfaction with sexual function.

Other Neurologic Disorders

Parkinson disease (PD) is often associated with low testosterone levels and therefore decreased sexual drive. 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 premature or delayed ejaculation. In women, decreased lubrication and involuntary urination can occur during intercourse. Treatment with dopamine and dopamine agonist medications, by contrast, have been documented to cause hypersexual behavior, which often accompanies mania. Hypersexuality has also been described with deep brain stimulation of the subthalamic nucleus.

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. Guillain-Barré syndrome has been linked to ED when there is residual neurologic deficit or disability after recovery.

Chronic Pain

The reasons for sexual dysfunction in patients with chronic pain are multifactorial, often related to physiologic, pharmacologic, and psychological factors. 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. In another study, sexual problems were reported in 46% of patients with low back pain. 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. Sexual dysfunction in patients with chronic pain has been correlated most strongly with the presence of depression, poor coping skills, and shorter pain duration. Many of the medications used to treat chronic pain (including opioids, antidepressants, and anticonvulsants) can independently contribute to sexual dysfunction.

Rheumatologic Disease

Osteoarthritis (OA) impacts sexual function primarily through associated joint pain, stiffness, and fatigue, and the hip joint is the most often implicated in leading to sexual difficulties. Total hip replacement often significantly improves sexual functioning; in one study, 65% of patients found relief from sexual difficulties after the surgery. 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.

Rheumatoid arthritis (RA), similar to OA, can cause problems in sexual functioning through joint pain, stiffness, and fatigue. RA in men has also been shown to be associated with decreased sexual desire and ED during periods of active inflammation. One 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. Difficulties in sexual performance were related to overall level of disability and hip involvement, whereas decreased sexual desire and satisfaction were correlated more with perceived pain, age, and depression.

Amputation

Patients with limb amputation usually have preserved sexual genital functioning (unless a comorbid condition, such as diabetes or cardiac disease, or the side effects of their medications play a significant detrimental role). 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. Preservation of the knee joint can be helpful for maintaining balance during sexual intercourse, although transfemoral amputees can use a pillow to aid in positioning. 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. Sexual dissatisfaction ranges from 13% to 75% among amputees, with increased levels of sexual dysfunction despite preserved sexual desire, and therefore deserves increased focus during postamputation reintegration counseling.

Diabetes Mellitus

Diabetes mellitus (DM) is one of the major comorbidities affecting people with disabilities, as its presence is a significant risk factor for subsequent stroke and amputation. DM plays a clear role in the development of sexual dysfunction in men. ED is three times more common in men with DM than in the general population, with prevalence estimates ranging from 35% to 75%. Premature ejaculation and hypoactive sexual desire disorder have also been documented in 40% and 25%, respectively, of men with diabetes. Diabetes-related sexual dysfunction in men is strongly correlated with glycemic control, duration of disease, and burden of diabetic complications. The pathogenesis of sexual dysfunction in DM is likely to be multifactorial, including vasculopathy, autonomic neuropathy, and diminished nitric oxide production, which leads to decreased neurogenic vasodilation.

Diabetes in women has a much less clear effect on sexual functioning, as research is limited and at times contradictory. The most commonly reported condition is sexual arousal disorder, with its accompanying decreased vaginal lubrication. Low sexual desire, decreased clitoral sensation, orgasmic dysfunction, and dyspareunia have also been infrequently reported. Factors for the development of sexual dysfunction in women with diabetes have been analyzed, and a far different picture has emerged than for men with diabetes. In women, there has been no documented correlation with diabetic complications, length of disability, or level of glycemic control. A recent metaanalysis demonstrated a relationship between sexual function and elevated body mass index. Associations have been previously shown for cardiovascular comorbidity, depression, and age.

Cardiac Disease

Cardiovascular disease is another common comorbidity in patients with disabilities. Hypertension, coronary artery disease, and congestive heart failure have all been associated with increased prevalence of sexual dysfunction. Hypertension is the most prevalent comorbidity among men with ED. ED has been noted in 40% to 95% of men with hypertension and is correlated with duration of hypertensive disease. Control of blood pressure often leads to restoration of erectile function. ED is also common in cardiac disease, with a prevalence of 42% to 75%. ED is often one of the earliest indicators of cardiovascular disease, and men (with or without disabilities) who present with ED with no obvious cause should be worked up for this potentially deadly comorbidity. It has been reported that 25% to 63% of women with cardiac disease experience sexual dysfunction, including decreased sexual desire, vaginal dryness, dyspareunia, decreased genital sensation, and decreased orgasmic ability.

Cardiac disease, especially after myocardial infarction has been sustained, is often associated with depression and anxiety, which contribute to sexual dysfunction. Other psychological factors that are likely to play a role include fear of recurrence of cardiac symptoms or fear of death with resumption of sexual activity. Cardiovascular deaths during sexual intercourse are actually very rare, with the rate in men estimated to be 0.2 per 100,000 and the risk in women 12 times lower than in men.

Many cardiovascular medications (including antihypertensives and digoxin) have been known to contribute to the sexual dysfunction seen in cardiac disease.

Depression

Depression is one of the most common comorbidities in patients with all types of disabilities, and it has been shown to contribute to sexual dysfunction in a variety of ways, including medical, pharmacologic, and psychosocial. There has been intense research and publicity about the sexual side effects of antidepressant medications, but untreated depression has also been strongly correlated with sexual dysfunction. Clinically, it can be difficult to distinguish whether a patient’s sexual dysfunction is secondary to the depression itself or to the antidepressant medication. In one study of 134 patients with major depressive disorder who were not taking any medication to treat their illness, hypoactive sexual desire was seen in 40% to 50% of men and women, decreased arousal was observed in 40% of women, ED was seen in 50% of men, and ejaculatory or orgasmic dysfunction was seen in 15% to 20% of men and women. Psychosocial factors in patients with depression that are likely to play a role in the development of sexual dysfunction include interpersonal relationship difficulties and poor body image and self-esteem.