Sleep Disorders
Tarannum Alam
Cathy A. Alessi
CLINICAL PEARLS
Sleep complaints must be interpreted with respect to the normal age-dependent changes in sleep.
Age-related changes in sleep include decreased sleep efficiency, increased sleep latency, earlier bedtime, earlier morning awakenings, more nighttime arousal, more daytime sleepiness, and a decrease in deep sleep.
Psychiatric disorders, particularly depression, are the most common etiology of sleep problems in community-dwelling elders presenting with insomnia.
Treatment for insomnia in older people requires careful consideration of the underlying causes because secondary insomnia accounts for 80% to 95% of cases in the geriatric population.
It is not appropriate to start an older patient on sedative-hypnotic agents without an assessment of the sleep complaints.
Sleep hygiene and cognitive behavioral therapy can reduce use of hypnotics in patients with insomnia.
Obstructive sleep apnea is a cause of excessive daytime sleepiness in older people.
Respiratory depressants, such as sedatives and alcohol, can worsen sleep apnea.
Sleep changes in dementia include frequent nighttime arousals, further decrease in stages 3 and 4 sleep, disturbances of the sleep-wake cycle, and “sundowning.”
Impaired sleep in nursing home residents is caused by medical illnesses, incontinence, neurodegenerative conditions, depression, certain medications, lack of physical activity, lack of bright light exposure, environmental factors, and frequent primary sleep disorders.
Referral for polysomnography is indicated if a primary sleep disorder such as sleep apnea or periodic limb movement disorder is suspected or for chronic insomnia where etiology is unclear.
Sleep complaints and disorders are common in the older population. More than half of community-dwelling older people have reported sleeping problems.1 In a 2003 National Sleep Foundation survey, approximately two thirds of older adults reported experiencing sleep problems at least a few nights a week. Fifty percent of community-dwelling older people use over-the-counter and/or prescribed sleeping medications. The magnitude of sleep problems is even higher in residents of long-term care facilities.2
Sleep is an active state that is as complex as wakefulness. It is hypothesized that sleep is caused by reciprocal interactions between sleep- and wake-promoting brain regions, which produces a flip-flop switch.3 Notable wake-promoting brain regions include serotonergic and noradrenergic cell groups in the pontine and midbrain reticular formation, histaminergic and hypocretinergic neurons in the posterior and lateral hypothalamus, and cholinergic cell groups in the basal forebrain. The preoptic region of the hypothalamus promotes sleep and predominantly contains sleep-active γ-aminobutyric acid (GABA)ergic neurons.4
The exact biologic function(s) of sleep is still a mystery, although it is well established that sleep is essential and that its deprivation leads to neurologic, autonomic, and biochemical changes. Sleep is believed to have restorative, conservative, adaptive, thermoregulatory, and consolidative functions. Disrupted sleep is a sign of several significant illnesses of old age, including depression, physical problems, and primary sleep disorders. Problems with sleep can adversely affect the quality of life in older people and can be associated with increased morbidity and mortality.5 Primary care clinicians caring for older patients should have a high index of suspicion for early recognition and intervention of sleep disorders. Also, the primary care provider must be able to distinguish age-related changes in sleep pattern from changes that are associated with medical illnesses and/or sleep disorders.
OVERVIEW OF SLEEP ARCHITECTURE AND SLEEP STAGES
Within sleep, two separate states have been defined, including nonrapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. NREM sleep is further subdivided into four stages on the basis of electroencephalographic (EEG) criteria. These stages roughly parallel a depth-of-sleep continuum, with stages 1 and 2 considered as light sleep and stages 3 and 4 considered as deep sleep. Stage 1 sleep is characterized by relatively fast EEG frequencies in the theta range (4 to 7 Hz). During stage 2 sleep, there is slowing of EEG frequency and an increase in EEG amplitude with appearance of sleep spindles and K complexes. Stages 3 and 4 of NREM sleep are defined by high-amplitude, low-frequency (1.5 to 3 Hz) delta EEG waves. Stages 3 and 4 together are also referred to as delta or slow-wave sleep. REM sleep, also referred to as paradoxical sleep, is a period of active sleep with EEG activation, complete atonia of muscles, and bursts of REM. Unlike NREM sleep, REM sleep is also marked by increased oxygen requirements, increased autonomic activity, and dreaming.
Sleep is normally entered through NREM, and both NREM and REM stages alternate with a period near 90 minutes in normal young adults. NREM sleep comprises 75% to 80% of the total sleep time. The remaining 20% to 25% of sleep is spent in REM sleep that occurs in four to six discrete episodes during the night. REM sleep predominates in the last third of night and is linked to the circadian rhythm.
CHANGES IN SLEEP WITH NORMAL AGING
Age-dependent changes in sleep architecture (stages of sleep) and pattern (the amount and timing of sleep) have been well described in the literature.6,7 The most notable change in sleep structure with aging is a decrease in slow-wave sleep (stages 3 and 4), with stages 1 and 2 sleep increasing or remaining unchanged. In persons older than 90 years, stages 3 and 4 may disappear completely. Other findings include an earlier onset of REM sleep and decreased total REM sleep but no change in the percentage of REM sleep. There is also a more equal distribution of REM sleep throughout the night in older people.
Changes in sleep pattern include decreased sleep efficiency (time asleep over time in bed), increased sleep latency (time to fall asleep), more nighttime arousals, earlier morning awakenings, and more daytime napping. The 24-hour total sleep time remains similar or slightly decreased. The significance of all these changes is unclear. Recent evidence suggests that certain age-related changes in sleep reflect a decrease in the ability to sleep rather than a decrease in the need for sleep.
Circadian rhythmicity also changes with age. Neuronal loss in the suprachiasmatic nucleus in the hypothalamus, which serves as the “body clock,” as well as decreased production of melatonin by the pineal gland with aging, weakens circadian rhythmicity in older people, resulting in less sleep at night but more during the day.
DIAGNOSTIC APPROACH/ASSESSMENT OF POTENTIAL SLEEP DISORDERS
Diagnosis of sleep disorders in older persons can be challenging. Patients may not report sleep complaints unless specifically asked for the symptoms. To aid in screening older patients for sleep problems, the National Institutes of Health Consensus Statement on the Treatment of Sleep Disorders of Older People (1991) suggested three simple questions for the clinician, which are as follows:
Is the person satisfied with his or her sleep?
Does sleep or fatigue intrude with daytime activities?
Does the bed partner or others complain of unusual behavior during sleep, such as snoring, interrupted breathing, or leg movements?
In one representative sample, the most common sleep complaints among community-dwelling older people included difficulty falling asleep (37% of the sample), nighttime awakenings (29%), and early morning awakenings (19%).8 Daytime sleepiness is also common. Transient sleep problems (<2 to 3 weeks) are usually situational. Persistent sleep problems require more detailed evaluation.
A sleep diary may be helpful in clarifying sleep habits. Each morning, in a sleep diary, the patient records his/her time in bed, estimated amount of sleep, number of awakenings, time of morning awakening, and any symptoms that occurred during the night. The physician should try to obtain corroborating evidence from the bed partner, if available.
Initially, it is important to rule out an underlying medical condition, substance abuse, or another mental health problem contributing to sleep complaints. A careful psychosocial history is essential to evaluate the potential role of depression and anxiety. A mental status examination to rule out dementia is also indicated. Changes in social and environmental circumstances such as relocation and bereavement should be addressed. A careful review of systems including questions about pain, nocturia, nocturnal cough, orthopnea, and other symptoms should be performed to seek treatable medical conditions contributing to sleep problems. A full medication history, including over-the-counter and herbal medications, is absolutely essential (see Table 20.1).
A focused physical examination based on positive findings from the history should also be performed. The history and physical examination should guide laboratory testing. On the basis of this initial assessment, further studies or objective evaluation may be indicated.
Polysomnography (PSG) is the gold standard for the evaluation of sleep.
During PSG, several physiologic variables are simultaneously recorded; the parameters include EEG, electromyogram (EMG), electrooculogram (EOG), electrocardiogram (EKG), airflow at the nose and mouth; respiratory effort; and oxygen saturation. The EEG, EOG, and EMG recordings are scored for stages of sleep, total sleep time, sleep-onset latency, and percentage of time in NREM versus REM sleep.
TABLE 20.1 DRUGS THAT INTERFERE WITH SLEEP | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
According to the recommendations of the American Academy of Sleep Medicine (1997), PSG is primarily indicated when a sleep-related breathing disorder, periodic limb movement disorder (PLMD), narcolepsy, or REM sleep behavior disorder (RBD) is suspected.9 PSG is also commonly used when the initial diagnosis is uncertain or treatments fail in patients with chronic insomnia. Some sleep experts recommend PSG before embarking on the treatment of chronic insomnia because primary sleep disorders are common in older people. However, PSG is not indicated for routine evaluation of transient insomnia or insomnia secondary to psychiatric disorders.
The multiple sleep latency test (MSLT) is primarily used in the diagnosis of narcolepsy. During this test, the individual is polygraphically monitored during five scheduled daytime naps. The MSLT records the latency (i.e., time to fall asleep) for each nap, the mean sleep latency, and the presence or absence of REM sleep during any of the naps.
Other methods for the assessment of sleep include wrist actigraphy, which is a relatively low-cost method. A wrist actigraph is a portable device about the size of a wristwatch, which estimates sleep-wake amount on the basis of wrist activity. It is particularly valuable for studying individuals who might have difficulty sleeping in a sleep laboratory, such as those with insomnia and the elderly. Patients are studied in their own environment for multiple nights. Although this method cannot be used to determine the cause of insomnia, it can help in the evaluation of its severity. It also provides information about daytime napping. Actigraphy on nursing home residents has documented the extreme fragmentation of sleep in this population, leading to ongoing studies to improve the quality and quantity of sleep in this vulnerable group of patients.
Referral to a sleep specialist for PSG is indicated in the evaluation of suspected primary sleep disorders. A sleep specialist can also be helpful in the evaluation and management of chronic sleep complaints, even if PSG is not indicated. The key points to be considered while evaluating sleep disorders in older patients are summarized in Table 20.2.
CLASSIFICATION OF SLEEP DISORDERS
Sleep disorders have been classified in various ways. The International Classification of Sleep Disorders (ICSD)10 is the most widely used. The ICSD Diagnostic and Coding Manual lists 88 sleep disorders with their diagnostic criteria. It also includes a differential diagnosis listing of sleep disorders that cause the two main sleep symptoms,
insomnia and excessive daytime sleepiness, and those that produce other symptoms.
insomnia and excessive daytime sleepiness, and those that produce other symptoms.
TABLE 20.2 KEY POINTS IN THE EVALUATION OF OLDER PATIENTS WITH SLEEPING DIFFICULTIES | |
|---|---|
|
The ICSD has classified sleep disorders into four major categories: (i) The dyssomnias, which are disorders of initiating and maintaining sleep and the disorders of excessive sleepiness; (ii) the parasomnias, which are disorders of arousal, partial arousal, and sleep-stage transition that intrude into the sleep process; (iii) disorders associated with medical or psychiatric disorders; and (iv) the proposed sleep disorders for which there is insufficient information to confirm their acceptance as a definitive sleep disorder.
The Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) lists another system of classifying sleep disorders, which is mainly used by psychiatrists and shows considerable overlap with ICSD.11 Table 20.3 classifies some of the sleep disorders commonly encountered by primary care clinicians.
SPECIFIC SLEEP DISORDERS
Insomnia
CASE ONE
A 78-year-old woman reports trouble sleeping. She takes a long time to get to sleep at night, wakes up frequently during the night, and wakes up early in the morning. Her husband died 1 year ago. Since then, she stopped going to the local senior center and dropped many other interests and activities.
CASE TWO
A 65-year-old man reports frequent nighttime awakenings. He is not well rested the next day but does not nap or fall asleep during the day. He reports burning chest discomfort at night.
TABLE 20.3 COMMON SLEEP DISORDERS, THEIR CLASSIFICATION AND ICD-9 CODES | |
|---|---|
|
Insomnia is a complaint of inadequate or nonrestorative sleep characterized by one or more of the following: Difficulty falling asleep, repeated awakening, inadequate total sleep time or poor quality of sleep, as reflected in daytime functioning. The definition of insomnia must also include a complaint of daytime dysfunction in the form of a change in alertness, energy, cognitive dysfunction, behavior, or emotional state. In contrast, people who are normal “short sleepers” may complain of decreased total sleep time, but there are no significant daytime consequences associated with the complaint.
The prevalence of insomnia increases with age. Epidemiologic studies have found that insomnia is the most common sleep disturbance in the older population, with up to 40% of those older than 60 complaining of difficulty falling asleep and/or maintaining sleep, and >20% reporting severe insomnia.1 There is a clear gender difference, with insomnia being more prevalent in women. A 1995 survey found that almost 70% of patients with chronic insomnia never discuss the problem with their physicians. Even when physicians are aware of the problem
and prescribe medication, adequate evaluation is often lacking.
and prescribe medication, adequate evaluation is often lacking.
Depending upon the time course, insomnia can be acute, subacute, or chronic. The ICSD defines acute or transient insomnia as persisting for no more than 1 week and subacute or short-term insomnia as lasting from 1 week to 3 months. Both transient and short-term insomnias are almost universal experiences and are categorized under the diagnosis of adjustment sleep disorder. Although situational insomnia often resolves spontaneously, it must be recognized that it can also represent the foundation of a long-term condition. Chronic insomnia frequently begins as a stress-related phenomenon. Therefore, early identification and intervention may play an important role in the prevention of chronic insomnia.
Insomnia can also be classified as primary or secondary. When insomnia is not related to other specific medical, psychiatric, or medication-associated conditions, it may be considered primary (i.e., psychophysiologic, idiopathic, or sleep-state misperception). Psychophysiologic insomnia predominantly involves somatized tension and learned sleep-preventing associations that result in the complaint of insomnia and associated decreased functioning during wakefulness. When the insomnia is related to a specific medical, neurologic, or other sleep disorder, substance abuse, or psychiatric condition, it is considered to be secondary insomnia. Secondary insomnia accounts for 80% to 95% of cases in the geriatric population. For example, the patient in Case One presents with symptoms suggestive of insomnia secondary to depression, whereas Case Two suggests insomnia secondary to gastroesophageal reflux disease.
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
