stroke - amyotrophic lateral sclerosis - Parkinson disease - multiple sclerosis -
sexuality
accidente cerebrovascular - esclerosis amiotrófica lateral - enfermedad de Parkinson
- esclerosis múltiple - sexualidad
Patients with chronic neurological diseases live with disorders that affect all aspects
of their life and environment[1].
Sexual dysfunction may be one of these many disorders. The causes that generate sexual
dysfunction can be classified as: a) primary – a product of a direct injury of the
anatomical structures involved in sexuality (nerves, pathways, cortex); b) secondary
to physical changes resulting from the disease (e.g. muscular atrophy, spasticity,
chronic fatigue) and c) tertiary, due to psychosocial changes in the patient (e.g.
low self-esteem, depression, discordant relationships)[2],[3].
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects the
pyramidal pathway along its first and second motor neurons. The survival after diagnosis
is approximately 20% at three to five years[4]. A reduction in both the interest and the sexual activity of patients with ALS and
their partners has been reported[5].
Multiple sclerosis (MS) is a chronic, autoimmune disease that affects the central
nervous system (CNS) by dual mechanisms: inflammatory and degenerative, leading to
demyelination and subsequent loss of neurons. It is the main cause of nontraumatic
neurological disability in young adults[6]. Sexual dysfunction is one of the main problems reported by MS patients; an Iranian
study showed that 40-80% of women with MS had some degree of sexual dysfunction[3].
Parkinson’s disease (PD) is one of the most common neurodegenerative diseases in the
elderly, affecting 1% of patients over 60 years and 0.3% of the general population.
It is manifested by motor and nonmotor symptoms as a result of nigrostriatal dopaminergic
denervation and extranigral neurodegeneration[7]. In Israel, one study found that both women and men with Parkinson’s disease show
lower levels of desire and arousal, and a higher rate of erectile dysfunction and
premature ejaculation[8].
Cerebrovascular diseases (CVDs), as well as their sequelae, are the world’s leading
cause of disability with more than five million people affected worldwide annually[9],[10]. In patients with stroke sequelae, negative changes in their sexual life have been
described[11].
Chronic diseases have a negative influence on intimate relationships and level of
sexual satisfaction[12] and many patients and their partners are forced to modify their sexual habits as
a consequence of their condition[13].
The CNS is actively involved in sexuality. Studies using functional nuclear magnetic
resonance imaging and positron emission tomography scans have shown that sexual stimuli
cause activation of the middle preoptic area and the anterior hypothalamus, two critical
areas, and triggers of animal precopulatory activity[1],[14],[15],[16],[17]. The studies also demonstrate that these areas are not the only ones involved in
human sexual behavior and confirm the activation and deactivation of multiple brain
areas in response to excitatory and inhibitory stimuli. These include the cingulate
cortex, temporal cortex, insula, caudate nucleus, hypothalamus, and the cerebellum[1],[15],[16],[17]. The fundamental circuit involved in sexuality is the middle preoptic area, paraventricular
nucleus and paragigantocellular nucleus, as well as their interconnections, the spinal
cord, and the genital and extragenital organs involved in sexual behavior. However,
there are excitatory and inhibitory influences from multiple central areas that modulate
sexual response according to the circumstances. The hypothalamus plays an important
role, since it is the link between the nervous system and the endocrine system and
is involved in the control of certain basic behaviors, such as appetite, aggressiveness
and sexual arousal[1],[16],[17],[18].
The complexity of control powered by the CNS is compounded by the fundamental role
played by the peripheral nervous system in the anatomy of sexuality. The associated
peripheral nerves and plexuses connect the sexual organs to the CNS[1],[14],[15]. In women, the pelvic organs, including the internal genitals, are innervated by
the autonomic nervous system through the upper, middle (inconstant) and inferior hypogastric
plexus. The external genitals, muscles and tissues of the perineum are innervated
mainly by the pudendal nerve, formed by the anterior branches of the sacral nerves
II, III and IV. The superficial branches of this nerve provide sensory innervation
to the vaginal lips and clitoris[1],[18],[19],[20]. In men, the nerves that innervate the genitals are branches of the pudendal nerve
and of the cavernous nerves. The pudendal nerve is responsible for the motor and sensory
innervation of the external genitalia. Also, the cavernous nerves are a combination
of sympathetic and parasympathetic afferent fibers, and constitute the autonomic nerves
of the penis. These nerves are responsible for the innervation of the erectile component
of the penis and ejaculation. The sympathetic center is at the level of the spinal
segments T10 to L3; the preganglionic neurons involved in the efferent parasympathetic
activity of the penis are located in the gray intermediate zone of the spinal cord,
between the 2nd and 4th sacral vertebra[1],[17],[18],[1]
[9],[21].
Sexuality, in its anatomical and functional sense, is not restricted exclusively to
the sexual organs. Furthermore, it incorporates the whole economy of the nervous system,
including the sense organs, connecting pathways and CNS processing capacity[18],[19],[20],[21].
Bearing this in mind, we analyzed the association between disability resulting from
four neurological diseases (ALS, MS, PD, CVD) and sexuality, measured with specific
scales. We considered that the impact of disability was not reduced to the mere reduction
of the patient’s mobility, but affected multiple spheres at the psychic and social
level, generating a significant impact on sexuality[1],[2]
[1],[22],[23],[24],[25],[26].
The objective of our study was to describe the presence of sexual dysfunction and
possible associated comorbidities in a population with chronic neurological diseases,
and relate the disability to sexual activity dysfunction.
METHODS
We conducted a case-control study on patients with ALS, MS, PD and non-acute stroke
(at least one year post-event) and disease-free sex-aged matched controls.
Internationally-validated disability scales were used on each pathology. The Amyotrophic
Lateral Sclerosis Functional Rating Scale was performed on ALS patients. It is a 12-item
scale that addresses bulbar, respiratory and motor involvement during activities of
daily living[27],[28]. Patients with MS were rated using the Expanded Disability Status Scale, which scores
patients’ abilities through eight disease-targeted functional systems[29]. To grade disability in PD patients we used the Movement Disorder Society – Unified
Parkinson Disease Rating Scale[30]. Finally, we scored non-acute stroke patients with the Modified Rankin Scale[31]. The scales were subclassified in the followings ranges to validate the disability
results; ALS-Functional Rating Scale: 48 points = without disability, 37–47 = mild
disability, 25–36 = moderate disability, ≤ 24 = severe disability; Expanded Disability
Status Scale: 0 points = without disability, 1–3 = mild disability, 3.5–5.5 = moderate
disability, ≥ 6 = severe disability; Unified Parkinson Disease Rating Scale: 0–50
points: without disability, 51–100 = mild disability, 101–150 = moderate disability
and ≥ 151 severe disability; Modified Rankin Scale: 0 points = without disability,
1 = mild disability, 2 – 3 = moderate disability, 4 – 5 = severe disability. We then
created the dichotomous variable “disability”, which scored 1 for the patients who
were rated as moderate or severe.
Sexual function was rated both in affected and control participants with the International
Index Erectile Function[32] for men and the Female Sexual Function Index[33] for women. Both scales address sexuality with a global scope and identify the different
areas that can be affected. Of these, we focused on global satisfaction and orgasm[32],[33]. The International Index Erectile Function scale was subclassified as follows. no
sexual dysfunction = 65 to 75 points; 1; mild sexual dysfunction = 43 to 64 points;
2: moderate sexual dysfunction = 21 to 43 points and; severe sexual dysfunction =
between 0 and 20 points. The Female Sexual Function Index scale was subclassified
as follows; without sexual dysfunction = 26 to 36 points; 1: mild sexual dysfunction
= 19 to 25 points; 2: moderate sexual dysfunction = 10 to 18 points and 3; severe
sexual dysfunction = < 10 points. We also created the dichotomous variable “sexual
dysfunction”, which scored 0 for those patients with none or mild impairment.
The Beck Inventory was performed on every patient to screen for depression, we considered
depression as ≥ 10[34].
The study was approved by the ethical committee of our institution and all patients
agreed to participate in the study and signed an informed consent form.
We used the SPSS V.20 software for data analysis. Chi-square, Student’s-t and logistic
regression tests were used when appropriate. Statistical significance was set at 5%.
RESULTS
We included 42 patients (20 men) with a mean age of 53.8 (SD: 11.24) and 29 controls
(12 men) with a mean age of 49.4 (SD: 19.33). Among the patients, nine had ALS, 12
MS, 13 PD and eight a history of stroke. Sexual dysfunction was present in 77.5% of
the patients and 22.5% of controls ([Tables 1] and [2]).
Table 1
Population characteristics.
|
Variable
|
Controls (n = 29)
|
Patients (n = 42)
|
|
Age (years)
|
49.4 (± 19.3)
|
53.8 (± 11.24)
|
|
Gender
|
Male: 41.4% (n = 12)
|
Male: 47.6% (n = 20)
|
|
Female: 58.6% (n = 9)
|
Female: 52.4% (n = 22)
|
|
Age (categories)
|
< 40: 38.0% (n = 11)
|
< 40: 11.8% (n = 5)
|
|
41 a 60: 31.0% (n = 9)
|
41 a 60: 59.8% (n = 25)
|
|
> 60: 31.0% (n = 9)
|
> 60: 28.4% (n = 12)
|
|
Related diseases
|
Yes: 51.7% (n = 15)
|
Yes: 69.0% (n = 29)
|
|
No: 48.3% (n = 14)
|
No: 31.0% (n = 13)
|
|
Currently a couple
|
Yes: 69.0% (n = 20)
|
Yes: 66.7% (n = 28)
|
|
No: 31.0% (n = 9)
|
No: 33.3% (n = 14)
|
|
Sexual activity with partner
|
Yes: 65.5% (n = 19)
|
Yes: 42.9% (n = 18)
|
|
No: 34.5% (n = 10)
|
No: 57.1% (n = 24)
|
|
Sexual activity in last 6 months
|
Yes: 72.4% (n = 21)
|
Yes: 45.2% (n = 19)
|
|
No: 27.6% (n = 8)
|
No: 54.8% (n = 23)
|
|
Pharmacological help
|
Yes: 3.4% (n = 1)
|
Yes: 4.8% (n = 2)
|
|
No: 96.6% (n = 28)
|
No: 95.2% (n = 40)
|
|
Depression
|
Yes: 13.8% (n = 4)
|
Yes: 47.6% (n = 20)
|
|
No: 86.2% (n = 25)
|
No: 52.4% (n = 22)
|
Table 2
Population characteristics by entity.
|
Variable
|
ALS (n = 9)
|
PD (n = 8)
|
MS (n = 12)
|
CVDs (n = 8)
|
|
Age
|
52.8 (± 10.8)
|
62.6 (± 7.4)
|
44.7 (± 8.55)
|
54.1 (± 10.59)
|
|
Gender
|
Male: 44.4%
|
Male: 62.5%
|
Male: 33.3%
|
Male: 50.0%
|
|
Female: 55.6%
|
Female: 37.5%
|
Female: 66.7%
|
Female: 50.0%
|
|
Age (categories)
|
< 40: 0.0%
|
< 40: 0.0%
|
< 40: 33.3%
|
< 40: 12.5%
|
|
41 a 60: 66.7%
|
41 a 60: 37.5%
|
41 a 60: 66.7%
|
41 a 60: 75.0%
|
|
> 60:33.3%
|
> 60: 62.5%
|
> 60: 0.0%
|
> 60: 12.5%
|
|
Related diseases
|
Yes: 66.7%
|
Yes: 75.0%
|
Yes: 75.0%
|
Yes:100.0%
|
|
No: 33.3%
|
No: 25.0%
|
No: 25.0%
|
No: 0.0%
|
|
Sexual activity in last 6 months
|
Yes: 33.3%
|
Yes: 25.0%
|
Yes: 75.0%
|
Yes: 50.0%
|
|
No: 66.7%
|
No: 75.0%
|
No: 25.0%
|
No: 50.0%
|
|
Pharmacological help
|
Yes: 0.0%
|
Yes: 0.0%
|
Yes: 8.3%
|
Yes: 12.5%
|
|
No: 100.0%
|
No: 100.0%
|
No: 91.7%
|
No: 87.5%
|
|
Depression
|
Yes: 66.7%
|
Yes: 50.0%
|
Yes: 25.0%
|
Yes: 50.0%
|
|
No: 33.3%
|
No: 50.0%
|
No: 75.0%
|
No: 50.0%
|
|
Disability
|
WT Dis: 0.0%
|
WT Dis: 25.0%
|
WT Dis: 0.0%
|
WT Dis: 0%
|
|
Mild: 11.1%
|
Mild: 62.5%
|
Mild: 8.3%
|
Mild: 75.0%
|
|
Moderate: 66.7%
|
Moderate: 12.5%
|
Moderate: 66.7%
|
Moderate: 25.0%
|
|
Severe: 22.2%
|
Severe: 0.0%
|
Severe: 25.0%
|
Severe: 0.0%
|
ALS: amyotrophic lateral sclerosis; PD: Parkinson’s disease; MS: multiple sclerosis;
CVDs: cerebrovascular diseases; WT Dis: without disability.
We performed a logistic regression with “sexual dysfunction” as the dependent variable
and age, depression and “disability” as the independent variables. All of them had
statistical significance, both in the univariate and the multivariate analyses (p
< 0.05). “Disability” had the greatest odds ratio (20.38, CI 95%: 2.5-165.86), followed
by depression (8.83, CI 95%: 1.67-46.76) and age (1.13, CI 95%: 1.04-1.23).
With regard to sexual dysfunction, 69% of controls had none, 10.3% had mild sexual
dysfunction and 20.7% had severe sexual dysfunction. In patients with ALS, 55.6% had
severe sexual dysfunction, 22.2% had moderate sexual dysfunction and 22.2% had no
sexual dysfunction at all. Considering those with MS, 66.7% had no sexual dysfunction,
16.7% mild sexual dysfunction and 16.7% had severe sexual dysfunction. In our series,
all patients with PD had sexual dysfunction: 23.1% had mild sexual dysfunction and
76.9% severe sexual dysfunction. Patients with a stroke history had the following
frequencies: 37.5% severe sexual dysfunction, 37.5% mild sexual dysfunction and 25%
none at all ([Figure 1]).
Figure 1 Sexual dysfunction by entity.ALS: amyotrophic lateral sclerosis; PD: Parkinson’s
disease; MS: multiple sclerosis; CVDs: cerebrovascular diseases.
In relation to sexual satisfaction, 59% of women reported impairment while only 40%
of men did ([Figure 2]).
Figure 2 Sexual satisfaction in females and males.
With reference to orgasm, this was altered in 60% of female patients but only in 40%
of male patients ([Figure 3]).
Figure 3 Orgasm function in females and males.
DISCUSSION
From our study population analysis, we can conclude that disability was the main variable
associated with sexual dysfunction, as has already been reported[1],[2]. This is a complex relationship that cannot be explained by means of a unique pathophysiological
mechanism. For example, in ALS, sexual dysfunction is most likely secondary to motility
restriction due to muscular atrophy and motor disability per se, as well as dyspnea and depression. In MS patients, on the other hand, strategic
CNS lesions affecting anatomic centers related to sexuality are probably responsible
for sexual impairment, along with social stigmatization, and both sensory and motor
dysfunction. Finally, in PD and stroke, adverse effects of commonly-used treatments
like beta-blockers and dopamine agonists also need to be considered as possible etiologies.
Beyond the probable mechanisms of each disease, living with a chronic pathology or
its sequelae implies that a considerable amount of time is spent in rehabilitation
or reminders of the disease (such as medical appointments, complementary studies,
etc.), which may have a negative impact on personal relationships and, of course,
sexuality[19].
Of the chronic neurological diseases considered in our study, ALS patients were the
most sexually disabled. As already stated, this may be secondary to mobility impairment,
forced vital capacity reduction and the burden of bearing a poor prognosis disease.
Noticeably, MS patients’ rating was similar to controls, possibly due to broader coping
abilities related to a younger age. Therefore, not surprisingly in PD, all patients
had at least some degree of sexual dysfunction.
One finding that captured our attention was the gender differences observed. In our
population, equally disabled women had higher sexual dysfunction scores than men.
It is possible that sexual dysfunction affects genders differently, but it is certainly
not clear how chronic diseases with similar motor impairment can affect females to
a greater extent[35],[36].
Our findings confirm the intuitive association of sexual dysfunction in patients with
some of the most disabling chronic neurologic diseases. We believe that the performance
of other studies targeted to a better understanding of the pathologic pathways involved,
and the offering of better therapeutic options, would be highly advisable[37]. We therefore believe that sexuality should be addressed during regular consultations,
because through the diagnosis of sexual problems, neurologists can offer both advice
and treatment, thus improving the patient’s quality of living.
