Background
Sleep disorders are commonly underdiagnosed and are a significant source of concern in the geriatric population. [1] Several diverse factors may contribute to sleep disturbances in a large percentage of the elderly population. These include retirement, health problems, death of spouse/family members, and changes in circadian rhythm. [2] Changes in sleep patterns may be part of the normal aging process; however, many of these disturbances may be related to pathological processes that are not considered a normal part of aging. [3, 4]
In addition to affecting quality of life—because of excessive daytime sleepiness, as well as physical, psychological, and cognitive problems [4] —sleep disorders have been implicated with increased mortality. [5, 6] In addition, the number of medications used tends to increase with age, which in itself can lead to increased morbidity, mortality, and side effects such as falls, [7] cognitive impairment, and even sleep disturbances. [8]
When a person experiences significant and prolonged sleep disturbance, they will generally contact their primary care provider for an evaluation. This evaluation may consist of a medical history review, concomitant medications, physical examination, lab work, and a Mental Status Examination. If the provider is unable to determine the underlying causality of the sleep disturbance, referral to a psychiatrist or sleep specialist may be necessary. At this point, a more in-depth examination is performed to rule out other potential contributing factors and to reach a diagnosis. Determining the causality of the sleep disturbance is imperative to be able to educate patients and caregivers about treatment alternatives.
Treating insomnia in the elderly can improve overall health, but care must be taken when medications are used in this particular population. [1] Treatments for insomnia include over-the-counter and prescription medications. However, non-medication treatment options are preferred and may lead to more durable benefits. Non-medication treatments include behavioral modification, relaxation techniques, sleep hygiene improvement, sleep restriction, light therapy, [9] cognitive-behavioral therapies, [3, 10] tai chi, yoga, meditation, acupuncture, and acupressure. [11] There is even an FDA-approved bedside device for insomnia that cools and pumps fluid to a forehead pad that is worn throughout the night. The device helps reduce latency to stage 1 and stage 2 sleep. [12]
Pathophysiology
Normal sleep is organized into different stages that cycle throughout the night. Polysomnographic studies have classified the sleep stages into rapid-eye-movement (REM) sleep and non-REM sleep
REM sleep (ie, paradoxical desynchronized sleep) is the stage of sleep during which muscle tone decreases markedly; this stage is associated with bursts of conjugate gaze and dreaming. Relative amounts of REM sleep are maintained until extreme old age, when they show some decline.
Non-REM sleep is subdivided into 4 stages. Stages 1 and 2 constitute light sleep, and stages 3 and 4 are called deep sleep or slow-wave sleep (SWS). With aging, an increase in the duration of stage 1 sleep and an increase in the number of shifts into stage 1 sleep occur. Stages 3 and 4 decrease markedly with age; in extreme old age (>90 years), stages 3 and 4 may disappear completely. Some studies, however, have found that elderly women tend to have normal or even increased stage 3 sleep, whereas men have normal or reduced stage 3 sleep.
Definitions
Time in bed
Older individuals spend more time lying in bed at night without attempting to sleep or unsuccessfully trying to sleep. They also use the bed for resting and napping during the day.
Total sleep period
Total sleep period refers to the time from sleep onset to the final awakening from the main sleep period of the day. Total sleep period increases with age because of the increase in the number of awakenings.
Total sleep time
Total sleep time refers to the total sleep period minus the time spent awake during the sleep period. Studies have found the total sleep time to be either reduced or unchanged in the older population.
Sleep latency
Sleep latency is the time from the decision to sleep to the onset of sleep. Studies have found considerable variability in individuals. In females, sleep latency has been related to increases in age and hypnotic drug use, which would decrease sleep latency.
Wake after sleep onset
Wake after sleep onset is the time spent awake from sleep onset to final awakening. An increase occurs in the time spent awake after sleep onset in the older population. Webb was able to attribute 38% of nocturnal arousals in a study to physical discomfort (eg, bladder distention, urinary urgency). [13] Pain, restless legs, and dyspnea have also been identified as factors in arousal during sleep.
Sleep efficiency
Sleep efficiency is the ratio of total sleep time to nocturnal time in bed. Most studies have found sleep efficiency to be decreased in the older population.
Nocturnal penile tumescence
Studies have shown that a gradual decline in nocturnal penile tumescence (NPT) during REM sleep occurs with age, even though the duration of REM sleep remains fairly constant until extreme old age.
Other changes
Few data describe cardiovascular changes during sleep in the older population. Zepelin found that auditory awakening thresholds from stage 4 sleep were significantly lower during the first night's sleep in a sleep laboratory in older men than in younger men. [14]
Older people spend more time in bed to get the same amount of sleep they obtained when they were younger; however, the total sleep time, at most, is only slightly decreased, with an increase in nocturnal awakenings and daytime napping. They often report having earlier bedtimes and an increased sleep latency (time to fall asleep), but excessive daytime somnolence is not part of normal aging. Older persons have been observed to be more easily aroused from sleep by auditory stimuli, suggesting increased sensitivity to environmental stimuli.
Etiology
Sleep apnea and periodic limb movements in sleep
Two primary sleep disorders that increase with age are obstructive sleep apnea (OSA) and periodic limb movements in sleep (PLMS).
OSA is the lack of breathing during sleep, and it can be obstructive (upper airway occlusion), central (primary neurologic disease), or mixed. People with OSA may experience waking with gasping, confused wandering in the night, and thrashing during sleep.
Because waking resolves OSA, avoid sedatives and hypnotics in these patients because such agents can further relax the pharynx dilators, thereby worsening the apnea. Martin et al found that among healthy older adults living in community settings, the prevalence of OSA (defined by more than 5 apneas per hour) was 28% in men and 20% in women. [15] They also found that among a random sample of patients in a medical ward, the prevalence of OSA was higher (33%). [15] This may be because of the high incidence of congestive heart failure (CHF) in this group. Significantly, many elderly inpatients are prescribed hypnotics, which can exacerbate OSA. OSA occurs in 42% of people with dementia who live in nursing homes and correlates with cognitive function.
An interaction between OSA and the cognitive deterioration of dementia is likely. [16, 17, 18] Sedative-hypnotic medications will likely exacerbate sleep apnea and are not recommended in patients with OSA. OSA can result in daytime hypersomnolence, systemic hypertension, cardiac arrhythmias, cor pulmonale, and sudden death.
PLMS, or nocturnal myoclonus, is repetitive, unilateral, or bilateral stereotyped leg jerks that arouse the patient from sleep. In a random sample of 427 older volunteers, 45% had PLMS; this statistic correlated with dissatisfaction with sleep, sleeping alone, and kicking at night. The incidence of nocturnal myoclonus increases with age, and the likelihood of an associated sleep-wake complaint is related to the absolute number and intensity of the leg movements.
Sundowning
Sundown syndrome is a behavioral phenomenon closely related to disturbed circadian rhythms [19] with incident rates of up to 66% in patients with dementia and those in nursing homes. [20, 21, 22, 23] Behaviorally, it is characterized by agitation, aggression, confusion, disorientation, and mood disturbances. [22, 24] Its name, “sundowning,” reflects that it is typically observed in the late afternoon or evenings. Sundowning behaviors have been associated with functional impairment, rapid decline of cognition, financial toll, caregiver burden, and increased risk of institutionalization. [23, 25]
Psychiatric disorders
Psychiatric illnesses such as dementia and depression are often associated with insomnia. [26, 27, 28] Of elderly patients with major depressive disorders, 50% report substantial sleep impairment. Clinical tools such as the Mini–Mental State Examination (MMSE) and/or Geriatric Depression Scale (GDS) should be used. An attempt should be made to manage the underlying condition before initiating treatment for sleep.
A patient who is depressed may experience an increase in sleep latency, a decrease in REM latency, prolonged initial rapid-eye-movement (REM) sleep, an increase in nighttime wakefulness, a decrease in slow-wave sleep (SWS), and early-morning awakening.
Patients with dementia, especially those with Alzheimer disease, have lower sleep efficiency; an increase in the length of stage 1 sleep; a decrease in stage 3, stage 4, and REM sleep; more sleep disruptions and awakenings; episodes of nocturnal wandering; and an increase in daytime napping. [29]
Personality and affective disorders can lead to poor sleep or subjective complaints of poor sleep. This can further manifest as early-morning wakefulness, a reduction of stage 4 sleep, and short REM latency, which is more pronounced in the older population. Bipolar disorders, schizophrenia, posttraumatic stress disorder (PTSD), and anxiety disorders can result in difficulty initiating and/or maintaining sleep.
Medications
Older patients take an average of 5–9 daily medications, some of which can interfere with sleep and wakefulness. Sedative antidepressants (eg, amitriptyline) and sedative neuroleptics (eg, chlorpromazine, clozapine) can cause impaired performance and daytime drowsiness. Avoid amitriptyline in older people because of the anticholinergic effects and possible confusion. Beta-blockers, especially lipophilic compounds (eg, metoprolol, propranolol), can cause difficulty falling asleep, an increased number of awakenings, and vivid dreams.
The chronic use of sedative-hypnotics often confounds normal sleep-wake functioning because of drug-withdrawal effects or daytime drowsiness. The xanthines theophylline and caffeine are stimulants that increase wakefulness while they decrease SWS and total sleep time. The effect of caffeine can last as long as 8-14 hours and may be more pronounced in older patients because of decreased caffeine clearance with decreased liver function. Furthermore, caffeine is present in many over-the-counter medications, including analgesics, cold or allergy remedies, and appetite suppressants.
Nicotine is also a stimulant and affects sleep in a manner similar to that of caffeine. Several studies have shown that people of all ages who smoke have more sleep disturbances than people who do not smoke, primarily difficulty falling asleep and decreased sleep duration.
Other causes
Other causes of sleep disorders in geriatric patients include the following:
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Chronic pain disorders (eg, osteoarthritis, metastatic diseases) are one of the most common reasons cited by the older population for poor sleep; osteoarthritis causing joint stiffness at night makes moving during sleep difficult and painful
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Left ventricular failure associated with orthopnea and paroxysmal nocturnal dyspnea can lead to frequent awakenings
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A Cheyne-Stokes breathing pattern attributable to a cardiac or cerebral cause (treatment of this disorder with respiratory stimulants or nocturnal oxygen therapy can often improve sleep)
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Patients with chronic obstructive pulmonary disease (COPD) have nocturnal worsening of hypoxemia, which occurs predominantly during REM sleep
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Lower urinary tract symptoms (LUTS), including benign prostatic hypertrophy and detrusor instability, may contribute to poor sleep
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Patients with Parkinson disease may experience urinary frequency and difficulty in turning over and getting out of bed, which leads to sleep fragmentation
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Tachyarrhythmias
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Gastroesophageal reflux disease (GERD)
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Constipation
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Pruritic skin conditions
Epidemiology
More than 50% of elderly people have insomnia. [30] Sleep disturbance or insomnia is the third most common patient complaint, ranking behind headaches and the common cold. Approximately 15% of the adult population in the United States has insomnia of significant enough severity to seek medical attention. Of the US population, 1.7% receive a hypnotic prescription annually, and another 0.8% purchase nonprescription sleep aids. Fifty million Americans occasionally take some form of sleep medication.
Older women are more likely to experience insomnia than older men. In a large epidemiologic study of people older than 70 years, 35% of women reported moderate to severe insomnia, compared to only 13% of men. [31] More than one half of people older than 64 years who live at home and two thirds of people older than 64 years who reside in a long-term care facility are estimated to have some form of sleep disturbance.
Prognosis
In addition to affecting quality of life, sleep disorders have been associated with increased mortality. Two primary sleep disorders that increase with age are obstructive sleep apnea (OSA) and periodic limb movements in sleep (PLMS). OSA can result in daytime hypersomnolence, systemic hypertension, cardiac arrhythmias, cor pulmonale, and sudden death. In a random sample of 427 older volunteers, 45% had PLMS, and they reported dissatisfaction with sleep, sleeping alone, and kicking at night. Yaffe et al suggested that older women with sleep-disordered breathing (SDB), characterized by recurrent arousals from sleep and intermittent hypoxemia, have an increased risk of developing cognitive impairment. [32]
In a study of SDB and nocturnal cardiac arrhythmias in older men, Mehra et al found that the likelihood of atrial fibrillation or complex ventricular ectopy (CVE) increased along with the severity of SDB. In addition, different forms of SDB were associated with the different types of arrhythmias. [33]
Polysomnography in 2,911 participants showed that the odds of atrial fibrillation and of complex ventricular ectopy increased with increasing quartiles of the respiratory disturbance index (a major index including all apneas and hypopneas). Central sleep apnea was more strongly associated with atrial fibrillation than with complex ventricular ectopy. In contrast, obstructive sleep apnea and hypoxia were associated with complex ventricular ectopy; participants in the highest hypoxia category had an increased odds of CVE compared with those in the lowest quartile. The results suggest that different sleep-related stresses may contribute to atrial and ventricular arrhythmogenesis in older men. [33]
Patient Education
Individuals should be made aware that obtaining 8 hours of sleep per night is not crucial. Sleep needs are individualized. Although one person may need 9 hours of sleep, another person may need only 5 hours. Also, the amount of sleep required may change with age. If a significant change in amount of sleep occurs but there are no disturbances in daily functioning, there shouldn't be a cause for worry. When significant disturbances in daily functioning have occurred, it is important to identify the cause of the sleep disturbance and discuss available treatment options.
A variety of treatment options are available for insomnia and do not necessarily include the use of prescription medications. However, if prescription medications are warranted, there are many to choose from. Certain medications should be avoided in the elderly population (see Medication).
Experts suggest stimulus control, [34] which means using the bed for only sleep and sex. If people are used to reading or watching television in bed, they are encouraged to leave the bedroom and engage in a relaxing activity elsewhere until they are sleepy and ready to return to bed.
Teaching patients muscle-relaxation techniques to reduce tension and promote sleep is also useful. Regardless of the underlying causes of insomnia, general habits should be practiced for good sleep.
Patients should be instructed to go to bed at the same time, wake up at the same time, and avoid daytime napping, caffeine, heavy meals, nicotine, alcohol, and exercise at bedtime. Sedentary elderly persons should be encouraged to start a daily exercise program in the morning, as moderate training (60 min/d) has been shown to improve sleep quality. [35] Another useful tool is to turn the bedroom into an environment that is quiet, dark, and cool and ultimately promotes sleep.
The Web sites below provide further education on insomnia. These sites have information on signs and symptoms, causality, preventive measures, complications, treatments, and even current enrollment in clinical trials for insomnia.
