Sleep Disorders in Older Adults
Author Affiliations: Mr. Birath is at the VA Greater Los Angeles Healthcare System, Geriatric Research, Education and Clinical Center, and the Fuller Theological Seminary, Graduate School of Psychology, Pasadena, CA; Dr. Kim is at the VA Greater Los Angeles Healthcare System, Sleep Medicine Fellowship Program, Los Angeles, CA; and Dr. Martin is at the VA Greater Los Angeles Healthcare System, Geriatric Research, Education and Clinical Center, and the David Geffen School of Medicine at the University of California, Los Angeles.
What Is Sleep?
Human sleep is composed of two separate states: rapid eye movement (REM) and non-REM (NREM) sleep. NREM is divided into four stages on a “depth of sleep” continuum. These stages cycle throughout the night from light sleep (stage 1) to deep sleep (stages 3 and 4), and back again about every 90 minutes. Research suggests that deep sleep is when physiological restoration of the body occurs.1 At the beginning of each 90-minute cycle, periods of REM sleep (also called “paradoxical sleep” because brain activity resembles wakefulness) occur. This is when most vivid dreaming occurs. During REM sleep, skeletal muscles are essentially paralyzed, a phenomenon known as REM atonia. Research suggests that REM sleep plays a role in memory consolidation and overall health.2
How Does Sleep Change with Age?
Sleep patterns and sleep quality change across the lifespan.3 The most notable change in older adults’ sleep architecture is a decrease in the amount of deep sleep (stages 3 and 4). The percentage of total sleep spent in REM sleep also decreases slightly. Older adults’ sleep is typically more fragmented than the sleep of young adults; however, among the healthiest older persons, sleep quality is generally maintained. The general population of older adults, however, exhibit multiple causes of sleep fragmentation, including sleep disorders (eg, sleep disordered breathing [SDB]), behavioral and lifestyle factors (eg, extended time in bed), and medical conditions (eg, arthritis). One common misconception is that older persons need significantly less nighttime sleep than their younger counterparts. In fact, the change in sleep need across adulthood is minimal, while multiple factors impact the ability of older adults to obtain sufficient sleep at night.
Older adults are more likely to experience daytime sleepiness and to take daytime naps as compared to younger adults. Studies estimate that 13-20% of older adults in the United States report significant daytime sleepiness.4 Daytime sleepiness typically results from insufficient or inadequate nighttime sleep, and for many older adults, daytime sleepiness negatively impacts quality of life.
Cultural differences play a role in napping behavior, and studies show that approximately one-quarter of older adults in the United States nap regularly.4 While some studies show immediate benefits of short naps (ie, less than 1 hour) on learning, memory, mood, and alertness, other studies show that regular “habitual” daytime naps are associated with negative health outcomes among older adults, including falls5 and overall mortality risk.4
The relationship between daytime and nighttime sleep is somewhat complex. It appears that much daytime sleepiness and daytime napping results from insufficient nighttime sleep. However, daytime napping (particularly naps longer than 1 hour) is associated with poorer quality nighttime sleep, including taking longer to fall asleep, shortened total time asleep at night, and more time awake during the night.
The body’s internal clock plays an important role in regulating sleep/wake cycles. Circadian rhythms change over the lifespan, and older adults often find their sleep is impacted by these changes.6,7 Typically, the timing of sleep shifts to an earlier time (ie, “advances”) from adulthood to old age. For some individuals, this change in the timing of sleep is benign; however, for others this change is problematic and leads to advanced sleep phase syndrome (ASPS; see section on “Advanced Sleep Phase Syndrome”).
As described above, some changes in sleep architecture and sleep timing are expected consequences of normal aging; however, the sleep problems of older adults are typically the result of sleep disorders, including SDB, periodic limb movement disorder (PLMD), restless legs syndrome (RLS), and ASPS, or can be due to the impact of medical conditions, medications, and psychiatric disorders on sleep. In addition, changes in lifestyle can impact sleep in older people and can lead to complaints of insomnia.
Insomnia is a complaint of insufficient or nonrestorative sleep, characterized by difficulty falling asleep, repeated awakening, inadequate total sleep time, or poor sleep quality, which is associated with poor daytime functioning.8 Insomnia can last a few days (transient insomnia), a few weeks (short-term insomnia), or can go on for more than a month (chronic insomnia). The type and duration of insomnia can help determine the approach to treatment.
Up to 40% of those over age 60 years complain of disturbed sleep, with more than 20% reporting severe insomnia. Women generally report more sleep problems than men, and Caucasians report more sleep problems than African Americans.7-11 True primary insomnia (ie, insomnia that is not attributable to a medical or environmental cause) is fairly rare among older adults, accounting for only 5-20% of cases.12 The majority of insomnia complaints among older persons are secondary to or comorbid with some other condition that impacts sleep quality. These conditions can include medical conditions, neurological disorders, primary sleep disorders, substance abuse, prescription medications, or psychiatric disorders. Among older adults, nocturia is a common problem that contributes to sleep disturbance. Approximately 30% of men over age 55 and 28% of women over age 60 get up at least twice per night to urinate.13,14 Table I lists medical and psychiatric conditions that commonly impact sleep and can lead to insomnia complaints among older adults. Generally, these conditions should be addressed simultaneously with treatment of insomnia to maximize therapeutic benefits.
Another important consideration in treating insomnia among older adults is that many prescribed and over-the-counter medications impact sleep, either by causing insomnia at night or by increasing sedation during the day. Substances such as alcohol, caffeine, and nicotine also impact sleep, and in general, should be avoided in the evening hours. Table II lists medications and substances that can adversely impact sleep either by causing daytime sedation or by directly disrupting nighttime sleep.
Diagnosis of insomnia includes an evaluation of sleep habits and patterns, as well as a medical and psychiatric history. Assessment should include not only nighttime symptoms, but also daytime functioning, including thoughts and behaviors that could affect nighttime insomnia. The diagnostic process might include completing a daily sleep diary, in addition to a diagnostic interview. Polysomnography (PSG), a comprehensive overnight recording of sleep, is generally not indicated in the initial evaluation of insomnia,13 but referral to a sleep specialist is indicated when the individual does not respond well to direct treatment of the insomnia.
Treatment. Because complaints of insomnia are so often comorbid with other conditions in older adults, these conditions must be considered in the approach to treatment. Recent research shows that it is not always necessary or desirable to delay treatment of insomnia and address suspected underlying causes first; however, it is critical to consider medical conditions and psychiatric disorders in tailoring interventions to an individual patient. For example, in an older adult at high risk for falls, pharmacotherapy may be contraindicated, and for an older adult with limited mobility, behavioral recommendations such as regularizing the sleep schedule and increasing time spent outdoors may be more appropriate.
Pharmacologic treatments for insomnia include medications that are Food and Drug Administration- (FDA) approved for the treatment of sleep problems (Table III) and other medications (eg, antidepressants, sedating antipsychotics) that are used “off-label.” In considering the appropriateness of pharmacotherapy for older adults, one must consider the risk profile of the medication (including risks of drug interactions), the degree of severity and type of sleep problem, the goals of treatment, and the overall health status of the individual. Recent findings suggest that newer hypnotic agents (benzodiazepine receptor agonists and melatonin receptor agonists) have fewer safety concerns than older hypnotic agents, and may be more appropriate for longer-term use.16 These medications decrease the time it takes to fall asleep, and some decrease awakenings during the night. Of greatest concern is the use of these agents in frail older adults since multiple studies have found an increased risk of falls among frail older adults taking benzodiazepines and other psychotropic medications.17-20 In addition, research shows that sleep problems are commonly caused or exacerbated by lifestyle/behavioral factors, which must be addressed in order for long-term improvements in sleep to be achieved; therefore, pharmacotherapy should always be accompanied by general sleep hygiene education.
Antidepressants, antipsychotics, antihistamines, and muscle relaxants are sometimes used to treat sleep problems because of their sedating side effects. It is important to consider that there are no controlled studies demonstrating that these medications are safe or effective in the treatment of insomnia. In the absence of a primary indication for the use of these medications (for example, it may be appropriate to use a sedating antidepressant to address the sleep complaint of a patient with depression), they are not recommended in the treatment of insomnia.16
Complementary and alternative therapies, particularly herbal supplements, are commonly used by individuals in an attempt to manage insomnia. A review of the literature on valerian and melatonin suggests that research does not support the use of these agents, and in the case of valerian, can cause adverse interactions with other prescription medications.21 Recent studies do suggest, however, that T’ai Chi Chih, a practice involving certain intentional poses and movements, can be helpful for older adults with moderate sleep complaints.22
Several randomized controlled trials and systematic reviews show that older adults with insomnia complaints can benefit greatly from nonpharmacologic interventions for sleep.23-25 There is a growing body of evidence for the use of cognitive-behavioral therapy for insomnia (CBT-I), which is a multicomponent approach designed to address multiple sleep issues concurrently (Table IV).
Sleep Disordered Breathing
Sleep disordered breathing is a condition characterized by periodic impairment of respiration during sleep. Apneas are complete cessations of respiration. Partial decreases in respiration are known as hypopneas. Respiratory events can be caused by obstruction of the upper airway (obstructive apnea), loss of ventilatory effort (central apnea), or a combination of the two. Sleep disordered breathing is typically diagnosed with PSG, in which airflow is recorded, usually in combination with respiratory effort, blood oxygen saturation, and other parameters. A diagnosis of SDB is typically made when 15 or more respiratory events (apneas plus hypopneas) occur per hour of sleep.
Sleep disordered breathing affects persons of all ages, and the prevalence increases with age. SDB is especially nefarious, not only because of its association with morbidity and mortality, but also because signs of SDB are often associated with aging. Snoring and daytime sleepiness are the most common presenting symptoms of individuals with SDB. While SDB is more common in younger men than younger women, this gender difference decreases greatly as a result of an increase in prevalence of SDB among women as they age. Rates of SDB are also higher in postmenopausal women than premenopausal women, higher in African Americans than in Caucasians, and higher in persons with hypertension as compared to those without hypertension.26 Prevalence rates vary, but are likely around 20% for adults over age 65.26,27
Treatment. The treatment of choice for SDB is continuous positive airway pressure (CPAP). This treatment involves applying positive pressure to the airway, which acts as a splint to prevent airway collapse during sleep. This is achieved by having the individual wear a mask over his or her nose during sleep, which is connected via a hose to a machine that generates positive air pressure. CPAP is highly effective in reducing the number of respiratory events. It is not curative, however, and individuals typically must use the CPAP machine indefinitely.
Other treatment options include the use of dental devices that reposition the jaw, weight loss, and surgery. Dental devices may be effective in alleviating SDB when obstruction occurs high in the airway. These devices are generally considered an alterative to CPAP rather than first-line therapy. Dental devices may reduce the severity of SDB among older adults with medical comorbidities.28 Weight loss is also sometimes suggested since fatty tissues in the neck can reduce the size of the airway and increase the likelihood of obstruction. While being overweight can contribute to SDB, and overweight individuals should be advised to lose weight as a part of treatment, weight loss alone is rarely sufficient to ameliorate SDB. Surgical procedures have been developed and are sometimes used to treat SDB. Interventions involve modifying the pharyngeal anatomy or bypassing the pharynx, and are curative for some individuals. The risks associated with surgical procedures among older adults must be carefully considered.
Periodic Limb Movement Disorder and Restless Legs Syndrome
Periodic limb movements (PLMs) involve repetitive, highly stereotyped movements during sleep, and are common among older individuals. Standard criteria define a PLM event as a series of four or more limb movements lasting 0.5 to 5 seconds with an inter-movement interval of 4-90 seconds. If PLMs occur more than 15 times per hour, the condition is considered pathologic.8 Periodic limb movement disorder occurs when PLMs are associated with complaints of insomnia and/or excessive sleepiness.7 PLMD is diagnosed using PSG, although less cumbersome and less expensive methods are currently being developed.
Sleep disorder centers report that individuals with PLMD are often significantly older than those without PLMD, and the disorder becomes more severe with age. Although prevalence data are not available using the criteria of 15 events per hour of sleep, a study using older diagnostic criteria (5 events/hr) found that the prevalence of PLMD in community-dwelling older adults was 45%, with no gender difference.27 A second study found that the number of PLM episodes increases with age, suggesting an increase in the prevalence of the disorder across the lifespan.30
Restless legs syndrome is closely related to PLMD. It is characterized by an irresistible urge to move the legs. These feelings typically occur at rest and improve with movement. It is common for the feelings to intensify later in the day and become problematic while the individual is in bed trying to fall asleep. The feelings in the legs are sometimes described as “restlessness,” “tingling,” or “itching.” RLS is diagnosed based on history. PLMD and RLS frequently coexist.
Treatment. Anecdotal evidence suggests that PLMD and RLS can be treated with hot or cold compresses, moderate exercise, or other therapeutic techniques; however, only one randomized study has examined the effectiveness of a nonpharmacologic treatment for PLMD.29 Pharmacotherapy has the most supporting evidence in the management of PLMD and RLS. Ropinirole is the only FDA-approved agent for the treatment of RLS. Dopaminergic agents are the primary treatments for PLMD and RLS. Depending on the severity of the symptoms, drugs such as carbidopa/levodopa may be used on an “as-needed” basis. Benzodiazepines and opioids, though effective in reducing the sleep disruption associated with PLMs, involve higher risk for older adults and are not typically considered first-line therapies. In addition, RLS can be associated with low levels of ferritin in the blood, and iron-replacement therapy is indicated in individuals with RLS whose ferritin levels are less than 45-50 mg/L.
Advanced Sleep Phase Syndrome
As mentioned above, ASPS is characterized by a sleep phase shifted earlier than normal or desired. Individuals become sleepy earlier than desired (eg, 7:00-8:00 PM), and wake up earlier than desired (eg, 3:00-4:00 AM). Although some older people try to counteract this by staying up until 10:00 or 11:00 PM, they often still awaken early in the morning due to internally-driven circadian rhythms. The resulting lack of sleep can contribute to sleep deprivation and daytime sleepiness. When the change in sleep timing leads to daytime difficulties for an older person, ASPS is diagnosed.
Advanced sleep phase syndrome has a prevalence of approximately 1% in middle-aged and older adults, and the rate increases with age. Men and women are equally affected. Typically, ASPS begins in middle adulthood, and, if left untreated, remains a chronic condition. Diagnosis typically involves the individual keeping a sleep diary and/or wearing a wrist actigraph (a device that records movement, which can be used to evaluate sleep patterns) for at least a week. It is important to differentiate between ASPS and insomnia in older adults, as they present with similar symptoms. Correctly identifying the condition will avoid ineffective or inappropriate treatments.
Treatment. It is important to treat ASPS comprehensively, since contributing factors often include both circadian rhythm changes and maladaptive behaviors. Bright-light therapy can be used to resynchronize the sleep/wake cycle to more appropriate times. To achieve the intensity levels required, outdoor sunlight or light from commercial light boxes can be used. Typically, an individual is exposed to light with intensity between 2500 and 10,000 lux for at least 30 minutes in the evening hours for 2-3 weeks.32 Because ASPS can be complicated by behavioral factors, sleep hygiene issues should also be addressed (Table IV).
An Overview of Indications for Overnight Sleep Studies
There are several conditions for which overnight sleep studies (PSG) is indicated. In particular, PSG is indicated for patients with suspected SDB, PLMD, violent or potentially harmful behaviors during sleep, neuromuscular disorders (eg, amyotrophic lateral sclerosis or post-polio syndrome) that are accompanied by otherwise unexplained sleep-related symptoms, and congestive heart failure that remains symptomatic despite optimal medical management. PSG is also indicated in the diagnosis of suspected sleep-related seizure disorders if clinical evaluation and standard electroencephalography prove to be inconclusive. PSG along with a multiple sleep latency test (MSLT) is indicated in cases of suspected narcolepsy.33 Though PSG is not routinely indicated for the diagnosis of insomnia, it is indicated in cases of insomnia that are unresponsive to treatment.34
Follow-up PSG is indicated to assess treatment response for patients with moderate to severe sleep apnea when a dental appliance or upper airway surgery has been used. Follow-up PSG to assess treatment response using CPAP may also be indicated in patients with symptoms that do not respond to adequate treatment or when symptoms return after initially responding to treatment. Patients who have had a significant change in body weight may need a repeat PSG if it is suspected that CPAP requirements have decreased following a significant weight loss or increased following a significant weight gain.33
PSG is generally not indicated for the diagnosis of RLS, circadian rhythm disorders, or chronic lung disease. Patients with a diagnosed seizure disorder who are without complaints suggestive of a sleep disorder should not be routinely referred for PSG. Common parasomnias that do not pose a threat to the patient or others, such as sleeptalking, enuresis, or bruxism, can usually be diagnosed clinically without PSG.
Unattended portable monitoring (PM) in the patient’s home or elsewhere outside of the sleep lab can be used as an alternative to PSG for the diagnosis of obstructive sleep apnea (OSA) in patients with a high pretest probability of OSA. Patients should be without significant comorbid medical conditions (including significant pulmonary disease, neuromuscular disease, or congestive heart failure) or suspected comorbid sleep disorders. PM should not be used for general screening for OSA in patients who are asymptomatic. Patients who have a PM study that is non-diagnostic for OSA should undergo PSG in the sleep lab. PM may be used to assess treatment of OSA involving a dental appliance, surgery, or weight loss.35
Sleep problems are common among older adults, and multiple factors impact the ability of older people to obtain adequate nighttime sleep. Sleep disordered breathing, periodic limb movement disorder, restless legs syndrome, and medical/psychiatric disorders can all contribute to the high prevalence of sleep complaints among older persons. When appropriate, older adults should be referred for overnight PSG. Treatment of sleep problems should focus on improving overall functioning and quality of life, and appropriate treatment should be available to older persons with sleep complaints.
Dr. Martin has received speaker honoraria from Medical Education Speakers Network. Mr. Birath and Dr. Kim report no relevant financial relationships.
This work was supported by NIH/NIA K23AG028452 (Martin).