Excessive Sleepiness   26  

Grace E. Dean, Michelle L. Klimpt, Jonna Lee Morris, and Eileen R. Chasens

OVERVIEW

Excessive sleepiness, sometimes called excessive daytime sleepiness, is common in older adults. Fatigue manifests as difficulty in sustaining a high level of physical performance; excessive sleepiness refers to the inability to maintain alertness or vigilance because of hypersomnolence. Many factors can affect nighttime sleep and result in daytime sleepiness in older adults. These include psychological disorders, symptoms of chronic illnesses (e.g., pain), medication side effects, environmental factors, and lifestyle preferences. Increases in sleepiness can result from age-related changes in chronobiology and sleep disorders. In older adults, the most common primary sleep disorders are OSA, RLS, and insomnia. The extent to which changes in sleep patterns experienced by older adults are caused by normal physiological alterations, pathological events, sleep disorders, or poor sleep hygiene remains unclear. Hospitalization and institutionalization can also interfere with sleep quality or quantity. There are many effective treatments for sleep disorders, but the first step is to identify the cause of excessive daytime sleepiness and then to quantify and aggressively treat this condition in the older adult. This chapter outlines an overview of sleep disorders common in older adults, describes how to assess sleep, and provides interventions to improve sleep in older adults.

BACKGROUND AND STATEMENT OF PROBLEM

The Institute of Medicine (Colten & Altevogt, 2006) reports that 50 to 70 million Americans are affected by chronic disorders of sleep and wakefulness. Recent data from the Behavioral Risk Factor Surveillance System (BRFSS) conducted by the Centers for Disease Control and Prevention (CDC) found that among community-dwelling persons older than 65 years (n = 23,167), nearly a quarter (24.5%) reported sleeping, on average, less than 7 hours in a 24-hour period and more than half (50.5%) of these older adults reported snoring (CDC, 2011b). Data from the 2005 to 2008 National Health and Nutrition Examination Survey (NHANES) show that 32% of persons older than 60 years (n = 3,716) slept less than 7 hours per night on weekdays or workdays (CDC, 2011a). Likewise, the Cardiovascular Health Study documented excessive sleepiness in 20% of subjects older than 65 years (n = 4,578; Whitney et al., 1998). Further, some sleep disorders are more common in patients in acute and chronic care settings. Ancoli-Israel et al. (1991) and Ancoli-Israel, Kripke, and Mason (1987) studied only persons older than 65 years and found undiagnosed sleep apnea in 24% of those living independently in the community, in 33% of those in acute care settings, and in 42% of older adults in nursing home settings.

CONSEQUENCES OF EXCESSIVE SLEEPINESS

The primary consequences of sleepiness are decreased alertness, delayed reaction time, and reduced cognitive performance (Ohayon & Vecchierini, 2002). The BRFSS found that nearly half (44%) of subjects in this telephone survey reported that they unintentionally fell asleep during the day at least once in the preceding month and that one out of 50 older adults had fallen asleep while driving in the preceding month (CDC, 2011a). The 2005 to 2008 NHANES data also show that older adults reported difficulty concentrating (18%) and remembering (14.7%) because of sleep-related problems (CDC, 2011a). Recent studies show that daytime sleepiness is significantly associated with declining cognitive function (Cohen-Zion et al., 2001), falls (Brassington, King, & Bliwise, 2000), cardiovascular events (Whitney et al., 1998) and higher levels of disability and depressive symptomatology (Anderson et al., 2014).

In the Cardiovascular Health Study, daytime sleepiness was the only sleep symptom associated with mortality, incident cardiovascular disease morbidity and mortality, myocardial infarction, and congestive heart failure, particularly among women (Newman et al., 2000). More recent, the risk for developing depression was examined in older women with few or no depressive symptoms at baseline, reports found poor sleep and objectively fragmented sleep at baseline indicated greater odds of worsening depressive symptoms 5 years later (Maglione et al., 2014). This link between sleep and medical conditions is consistent with the 2005 to 2008 NHANES results that demonstrated a greater rate of sleep-related problems with concentration, memory, and activities of daily living among women (CDC, 2011a).

Sleep problems, such as changes in sleep architecture and an increased incidence of OSA, are prevalent among persons with Alzheimer’s disease (Harper, 2010). Persons with Alzheimer’s disease demonstrate a pattern of decreased slow-wave sleep similar to older adults with normal aging. However, patients with Alzheimer’s disease also exhibit greatly reduced rapid eye movement (REM) sleep and decreased stability of their circadian sleep–wake cycle that is not part of normal aging. Frequently, before the diagnosis of a permanent neurocognitive disorder, an evaluation of sleep is performed to rule out impaired cognitive functioning resulting from a potentially treatable sleep disorder. Research suggests that improved sleep consolidation may be neuroprotective. According to Lim, Kowgier, Yu, Buchman, and Bennett (2013), better sleep consolidation, sleep that is uninterrupted by repeated awakenings, reduces the effect of apolipoprotein E (APOE) ε4 allele, the most well established genetic risk factor for Alzheimer disease. Nearly 700 community-dwelling older adults without dementia participating in the Rush Memory and Aging Project were monitored with up to 10 days of actigraphy to quantify sleep consolidation and ascertain APOE genotype over 6 years. Better sleep consolidation substantially reduced the negative impact of the ε4 allele on incidence of Alzheimer’s disease risk, leading the investigators to conclude that interventions to enhance sleep consolidation should be studied as potential means to reduce the risk of Alzheimer’s disease in APOE ε4+ individuals (Lim, Kowgier, Yu, Buchman, & Bennett, 2013).

PHYSIOLOGICAL CHANGES IN SLEEP THAT ACCOMPANY AGING

Normal changes in sleep that occur as part of human development and lifestyle choices must be differentiated from pathological sleep conditions, which are common among older adults. Although older adults require as much sleep as younger adults, older adults may divide their sleep between nighttime slumber and daytime naps, rather than a single consolidated period. The endogenous circadian pacemaker, located in the suprachiasmatic nucleus, along with exogenous environmental cues and a homeostatic need for sleep, mediate the normal wake and sleep pattern. With aging, the circadian pattern for sleep–wake decreases in amplitude, possibly in association with less robust changes in core body temperature (Richardson, Carskadon, Orav, & Dement, 1982). Compared with younger adults, healthy older adults have a more pronounced biphasic pattern of sleepiness during the afternoon hours (about 2–6 p.m.) and a phase advancement of nighttime sleepiness earlier in the evening (Roehrs, Turner, & Roth, 2000).

Changes in sleep architecture associated with normal aging include increased difficulty in falling asleep, poorer sleep quality with decreased sleep efficiency (SE), more time awake after sleep onset, increased “light” sleep (stages 1 and 2 sleep), and decreased quantity and amplitude of restorative “deep” slow-wave sleep (stages 3 and 4). Although older women report more sleep disturbances than older men, studies indicate that their sleep is less disturbed than that of men (Rediehs, Reis, & Creason, 1990). Gender partially accounts for differences in the outcomes of poor sleep quality in older adults. Women report more difficulty then men sleeping at night but studies indicate that their sleep is objectively less disturbed. When women and men both sleep less than 7 hours at night, men report better next-day function the following day (Krishnan & Collup, 2006). A cross-sectional study of community-dwelling older adults examined the independent association between nighttime sleep and daytime napping for all-cause mortality for 19 years from baseline. Increased mortality was associated in women sleeping more than 9 hours per night and in men napping 30 minutes or more during the day (Jung, Song, Ancoli-Israel, & Barrett-Connor, 2013).

PRIMARY CAUSES OF EXCESSIVE DAYTIME SLEEPINESS

Obstructive Sleep Apnea

OSA is a condition in which intermittent pharyngeal obstruction causes cessation of respiratory airflow (apneas) or reductions of airflow (hypopneas) that last for at least 10 seconds. This results in a microarousal that restores upper airway patency, permitting breathing and airflow to resume. According to the American Academy of Sleep Medicine (AASM, 2005) Task Force, OSA is diagnosed when these events occur at a rate of greater than 5 per hour of sleep and is accompanied by daytime sleepiness and impaired daytime functioning. It is common for patients with severe symptoms to experience multiple arousals during the night. These multiple arousals severely fragment sleep, preventing the deep sleep (stages 3 and 4) and REM sleep necessary for healthy mental and physical functioning.

OSA is both an age-related and an age-dependent condition, with an overlap in both distributions in the 60- to 70-year-old age range (Bliwise, King, & Harris, 1994). Age-related risk factors for OSA in older adults include an increased prevalence of overweight and obesity. Conversely, age-dependent risk factors include increased collapsibility of the upper airway, decreased lung capacity, altered ventilatory control, decreased muscular endurance, and altered sleep architecture (Brassington et al., 2000; Edwards et al., 2014). Treatments for OSA depend on the contributing pathology and patient preference and include nocturnal positive airway pressure, surgical procedures designed to increase the posterior pharyngeal area, oral appliances, and weight reduction when obesity is a contributing factor. Nasal continuous positive airway pressure (CPAP) therapy, which is highly effective when individually titrated to eliminate apneas and hypopneas, is currently the gold standard for treating OSA (Morgenthaler et al., 2006). Older adults tolerate CPAP therapy, with patterns of compliance similar to that of middle-aged adults (Weaver & Chasens, 2007). Although oral appliances offer a low-tech treatment option, they require a stable dentition that may be problematic for persons with extensive tooth loss or dentures.

Insomnia

Insomnia can be defined as delayed sleep onset, difficulty in maintaining sleep, premature waking, and/or very early arousals that result in insufficient sleep (American Psychiatric Association, 2013; Ancoli-Israel & Martin, 2006). Insomnia can be transient or chronic, and the perception of sleep loss may not correspond to objective assessment. The frequent awakenings suggestive of insomnia may be a conditioned arousal response because of environmental (e.g., noise or extremes of temperature) or behavioral cues. Anxiety associated with emotional conflict, stress, recent loss, feeling insecure at night, or significant changes in living arrangements can also produce insomnia (Ancoli-Israel & Martin, 2006). Chronic insomnia can result in a conditioned response of anxiety and arousal at bedtime in anticipation of difficulty falling asleep; this may prompt the use of hypnotic medications, over-the-counter (OTC) drugs, or alcohol. Although the use of hypnotics may produce short-term relief, they also affect sleep architecture and consequently lead to deterioration of sleep quality. The cycle of dependency and substance abuse is a potential problem in this age group (see Chapter 20, “Reducing Adverse Drug Events”). At this time, the general recommendation is, when hypnotics are indicated, the most short-acting drug should be selected and, optimally, used in conjunction with an appropriate behavioral intervention (Ancoli-Israel, 2000).

Risk factors for insomnia include older age, being female, comorbidities, shift work, and possibly lower socioeconomic status (Schutte-Rodin, Broch, Buysse, Dorsey, & Sateia, 2008). Both the cause and duration of insomnia should inform the choice of treatment. For example, insomnia associated with a psychological origin, such as depression or anxiety, is best treated from that perspective. If pain is affecting sleep, pain management should be addressed first and strategies to promote sleep onset should be added secondarily. Short-term pharmacotherapy may be appropriate if insomnia is situational and of recent onset. When insomnia has been “learned” and the behavior becomes chronic, behavioral interventions are most appropriate. Behavioral treatments for insomnia include stimulus control, progressive muscle relaxation, paradoxical intention, sleep restriction, biofeedback, and multifaceted cognitive behavioral therapy (CBT; Morin et al., 1999). Data show that 70% to 80% of patients benefit from behavioral therapies and that improvement in sleep is often sustained for a minimum of 6 months after treatment. Recently, a brief, 4-week, group-based CBT program in adults (mean age = 64 years) with sleep-maintenance insomnia produced robust and durable improvements in sleep quality and daytime functioning that was maintained at 3-month follow-up compared to the waitlist group (Lovato, Lack, Wright, & Kennaway, 2014).

Restless Legs Syndrome

RLS is a neurological condition that is characterized by the irresistible urge to move the legs. It is usually associated with disagreeable leg sensations that become worse during inactivity and often interferes with initiating and maintaining sleep. As a secondary condition, this movement disorder can be caused by iron deficiency anemia, uremia, neurological lesions, diabetes, Parkinson’s disease, rheumatoid arthritis, or it can be a side effect of certain drugs (e.g., tricyclic antidepressants, serotonin reuptake inhibitors, lithium, dopamine blockers, xanthines). Periodic leg movement disorder (PLMD) is a similar condition, but it is characterized by involuntary flexion of the leg and foot that produces microarousals or full arousals from sleep that interfere with achieving and maintaining restorative slow-wave sleep (stages 3 and 4). Although the etiology and associated mechanism of this specific movement disorder are not well defined, this condition has been linked to metabolic, vascular, and neurologic causes (Claman et al., 2013). Dopaminergic drugs are the most effective agents for treating RLS and PLMD as well as opioids, benzodiazepines, anticonvulsants, adrenergics, and iron supplements. However, their efficacy for long-term treatment in older adults has not been sufficiently evaluated (Ancoli-Israel & Martin, 2006; Gamaldo & Earley, 2006).

SECONDARY CAUSES OF EXCESSIVE DAYTIME SLEEPINESS

Medical and psychiatric illness can interfere with sleep quality and disturb sleep. For example, depression or anxiety appear to have a bidirectional relationship with insomnia (Buysse, 2004). Painful chronic conditions, such as arthritis, reduce SE, or simply changing body position may be painful enough to cause awakenings. Nighttime voiding, or nocturia, worsens sleep in older individuals with insomnia. However, it is unclear whether the urge for urination causes the awakenings or whether some other cause of awakening led to the need for urination (Zeitzer, Bliwise, Hernandez, Friedman, & Yesavage, 2013).

Because older adults frequently have multiple medical conditions, they are also more likely to take OTC and prescription medications for symptom relief. However, many medications and nonprescription drugs (e.g., pseudoephedrine, alcohol, caffeine, and nicotine) interfere with sleep. Thus, health care providers must be acutely aware of which OTC medications and beverages can cause sleep problems. Symptom management must be balanced against preventing polypharmacy in older adults to maintain sleep quality (Ancoli-Israel, 2005).

Sleep Disturbance During Hospitalization

Studies have shown that as many as 22% to 61% of hospitalized patients experience impaired sleep (Redeker, 2000). Many older adults have primary sleep disorders (OSA, insomnia, RLS) and these conditions can become more pronounced or acute during acute illness and hospitalization. Sleep disorders may go unrecognized in acute care settings, thus patients may experience acute sleep deprivation concurrently with a medical crisis or surgical intervention.

Protecting sleep and monitoring sleep quality should be routine elements of care in hospital settings (Young, Bourgeois, Hilty, & Hardin, 2008). There are three common causes for sleep disruption in hospitals that are often overlooked by nursing staff: noise, light, and patient-care activities (Redeker, 2000). Further, anesthesia, cardiopulmonary disorders, and pain medications can reduce the respiratory drive and lead to hypopnea and apnea. Medications typically administered postoperatively can affect alertness by causing excessive sedation, changes in sleep architecture, decreased REM sleep, nightmares, or insomnia. Pain and anxiety may also cause older patients to have insomnia. Inadequate sleep impedes healing and recovery and may be associated with acute mental confusion in older adults (Young, Bourgeois, Hilty, & Hardin, 2009).

TABLE 26.1

Sleep History

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