Sleep and Sleep Disorders

BACKGROUND

There have been major advances in understanding sleep and sleep problems in both children and adults over the past several decades. This began with the advent of polysomnographic (PSG) sleep recording in the 1950s and the description of the rapid eye movement (REM) and non-rapid eye movement (NREM) sleep (see Table 21.1). Sleep Disorders Medicine has now been recognized in its own right and includes a pediatric section. Consensus on nosology and classification and the development of both sleep laboratories and clinical training programs have advanced the field (Baroni & Anders, 2018).

THE ORGANIZATION OF SLEEP: DEVELOPMENTAL ASPECTS

The organization of sleep-wake patterns has marked developmental aspects. Adults spend about 80% of their sleep time in NREM sleep (20% in REM). In contrast, newborn infants spend about half of their time in REM sleep. By adolescence, children achieve the pattern of sleep organization seen in adults (see Table 21.1). Other differences include the pattern of sleep. Thus when adults begin to sleep they typically start in stage 4 of NREM sleep and spend a considerable initial period in this sleep stage before the REM-NREM cycles recur, at intervals of about 90 minutes, during the night. Proportionally most of the REM sleep occurs in the latter part of the sleep cycle in adults. Interestingly infants have sleep patterns associated with an initial REM period and with REM and NREM sleep alternating through much of the night. The gradual reorganization of the sleep cycles begins early in life as central timing mechanisms become more active.

For the developing infant (and for the parents) the regulation of sleep-wake cycles and the ability to sleep through the night are important tasks that provide important opportunities for interaction and set the stage for other aspects of self-regulation. Difficulties in this process thus typically require some assessment of psychosocial and parent-child issues that might be having an impact. Factors important in this include the infant’s temperament and background of the caregivers, their supports, etc. Cultural, family, and other environmental influences may be important as are other potential variables such as physical condition of the infant and mother. There are frequently complicated interactions between the infant’s sleep pattern and the entire family’s ability to sleep through the night. In clinical practice all possible permutations and combinations are seen, for example, some infants may sleep/nap better in
day care or with a nanny than with the parents. Occasionally, infants will sleep better with one parent or the other.

TABLE 21.1 Features of NREM Sleep and REM Sleep

NREM Sleep	REM Sleep
EEG: synchronized, slower frequencies and higher voltages than wakefulness and REM	EEG: desynchronized, mixed, low-amplitude fast frequencies, similar to wakefulness
Reduced metabolic activity	Increased metabolic activity
Autonomic slowing	Autonomic activation
Maintained thermoregulation	Altered thermoregulation: poikilothermia
Episodic, involuntary movements	Skeletal muscle atonia
Slow rolling eye movements	Rapid eye movements
Few penile erections or little vaginal lubrication	Partial or full penile erections or significant vaginal lubrication
Limited mentation/dreaming	Dreaming
Defined as quiet sleep in infants	Defined as active sleep in infants
Sleepwalking and sleep terrors arise from NREM sleep	Nightmares arise from REM sleep
EEG, electroencephalogram; NREM, non-rapid eye movement; REM, rapid eye movement. Reprinted with permission from Baroni, A., & Anders, T. F. (2018). Sleep disorders. In A. Martin, M. H. Bloch, & F. R. Volkmar (Eds.), Lewis’s child and adolescent psychiatry: A comprehensive textbook (5th ed., p. 581). Wolters Kluwer.

TABLE 21.2 Differences Between Sleep in Infants and Adults

	Infants	Adults
NREM/REM %	50/50	80/20
Ultradian Cycle Length	50-60 min	90 min
Circadian Cycle	Polyphasic	Diurnal
Temporal Distribution of NREM/REM During the Night	Equi-distributed	First third/last third
Sleep Stages	Quiet Sleep (NREM) Active Sleep (REM)	NREM (N1-N2-N3) REM
NREM, non-rapid eye movement; REM, rapid eye movement. Reprinted with permission from Baroni, A., & Anders, T. F. (2018). Sleep disorders. In A. Martin, M. H. Bloch, & F. R. Volkmar (Eds.), Lewis’s child and adolescent psychiatry: A comprehensive textbook (5th ed., p. 581). Wolters Kluwer.

Table 21.2 summarizes some of the differences between sleep in infants and adults, and Table 21.3 summarizes changes in sleep duration over the course of development. As Baroni and Anders (2018) note, the sleep-wake cycle has two important elements. One is more homeostatic and sleep dependent and varies with the awake time that precedes sleep, whereas
the second process has more to do with circadian rhythms reflecting both internal central nervous system (CNS) factors and the body’s internal clock and the day-night light cycle.

TABLE 21.3 Sleep Durations in Childhood and Adolescence

	Mean Nighttime Sleep Duration (hours)	Mean Daytime Sleep Duration (hours)
6 mos old	14.2	3.4
3 yrs old	12.5	1.7
6 yrs old	11	—
10 yrs old	9.9	—
12 yrs old	9.3	—
15 yrs old	8.5	—
Reprinted with permission from Baroni, A., & Anders, T. F. (2018). Sleep disorders. In A. Martin, M. H. Bloch, & F. R. Volkmar (Eds.), Lewis’s child and adolescent psychiatry: A comprehensive textbook (5th ed., p. 582). Wolters Kluwer.

FIGURE 21.1. Polygraphic recording of rapid eye movement (REM) sleep. An epoch of REM sleep in a newborn infant characterized by a low-voltage, fast electroencephalogram (EEG); active rapid eye movements (arrows); an inhibited electromyograph (EMG); and rapid irregular respirations (RESP). EOG, electrooculogram. Reprinted with permission from Anders, T. F. (2007). Sleep disorders. In A. Martin & F. R. Volkmar (Eds.), Lewis’s child and adolescent psychiatry: A comprehensive textbook (4th ed., p. 630). Lippincott Williams & Wilkins.

The electroencephalogram (EEG) pattern during REM sleep is characterized by fast, low-voltage activity similar to that observed while the individual is awake. During REM sleep, there are bursts of eye movements and rapid, irregular breathing and heart rate patterns. Dreams are reported during REM sleep. Thus while the individual appears to be sleeping, significant CNS activity is noted. This is observed in infants where it is sometimes referred to as “active sleep.” In contrast to the apparent activation during REM sleep, the pattern during NREM sleep is one associated with inhibition, for example, slow and regular heart and breathing rate with EEG activity showing slower frequencies. In babies, this stage is also referred to as quiet sleep. Figures 21.1 and 21.2 illustrated PSG recordings during REM and NREM sleep.

FIGURE 21.2. Polygraphic recording of non-rapid eye movement (NREM) sleep. An epoch of NREM sleep characterized by high-voltage, slow waves on the electroencephalogram (EEG); an absence of rapid eye movements; a tonic electromyograph (EMG) pattern; and slowed, regular respirations (RESP). EOG, electrooculogram. Reprinted with permission from Anders, T. F. (2007). Sleep disorders. In A. Martin & F. R. Volkmar (Eds.), Lewis’s child and adolescent psychiatry: A comprehensive textbook (4th ed., p. 630). Lippincott Williams & Wilkins.

CLASSIFICATION OF SLEEP DISORDERS IN CHILDREN AND ADOLESCENTS

There are two separate major approaches to diagnosis: they are largely, but not entirely, overlapping. One in the International Classification of Sleep Disorders, Third Edition (ICSD-3) (Mindell et al., 2006) and the second approach is that of Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5; American Psychiatric Association [APA], 2013). The former is oriented more for use by sleep specialists and the latter to general use; there are some differences in the two systems. To further complicate issues of diagnosis for younger children, there is yet another approach, which is the Diagnostic Classification: Zero to Three, Revised (DC 0-3R); this includes sleep disorders as well (Zero To Three Press, 2005). An important strength of DSM-5 is that it makes it possible to denote sleep disorders that are concurrent with mental health disorders—if this is justified, that is, if the sleep problem is not simply secondary to the mental health disturbance. The main categories of sleep disorder in the DSM-5 and ICSD-3 are summarized in Table 21.4. There are some differences and many similarities. The DSM-5 includes idiopathic hypersomnia and hypersomnia associated with a mental disorder. The DSM-5 approach is, of course, not limited solely to sleep. This discussion here follows the DSM-5 classification.

It is important to note that sleep disorders clearly vary with age. Infants have the most trouble with falling asleep and then with night awakening, whereas older children may have sleeping walking and adolescents are more likely to have insufficient sleep and circadian rhythm disorders (Baroni & Anders, 2018).

SPECIFIC SLEEP DISORDERS

Insomnia

Difficulties in going to bed or falling asleep and staying asleep as well as frequent nighttime awakening are the most frequent features of childhood insomnia. The child may, for example,
only want to fall asleep with the caregiver rather than on their own. The child may resist bedtime. As Baroni and Anders (2018) note, these have had various terminologies and classifications in the past.

TABLE 21.4 Main Categories of Sleep Disorders in DSM-5 and ICSD-3

Category	Description
Insomnia	Persistent difficulties sleeping Adequate opportunity for sleep Daytime impairment (e.g., chronic insomnia)
Sleep-related breathing disorders	Irregular breathing during sleep, possibly accompanied by sleep disruption (e.g., obstructive sleep apnea)
Hypersomnolence disorder and narcolepsy	Excessive daytime sleepiness, in spite of adequate sleep (e.g., narcolepsy, hypersomnolence disorder)
Circadian rhythm disorders	Misalignment of circadian rhythms and social requirement (e.g., delayed sleep phase)
Parasomnias	Abnormal physical and emotional experiences during sleep or sleep-wake transitions (e.g., sleepwalking, nightmares)
Sleep-related movement disorders	Presence of movements that delay sleep onset or disrupt sleep (e.g., restless leg syndrome)
DSM-5, Diagnostic and Statistical Manual of Mental Disorders, 5th Edition; ICSD-3, International Classification of Sleep Disorders, Third Edition. Reprinted with permission from Baroni, A., & Anders, T. F. (2018). Sleep disorders. In A. Martin, M. H. Bloch, & F. R. Volkmar (Eds.), Lewis’s child and adolescent psychiatry: A comprehensive textbook (5th ed., p. 585). Wolters Kluwer.

Daytime difficulties can include a range of problems including irritability, behavioral difficulties, overactivity, and chronic tiredness (Reid et al., 2009). Although this can start at any age, it is not typically diagnosed until after children are 6 months or so of age when more typical sleep patterns are established (Reid et al., 2009). Rates of 20%-30% are reported in community samples (Honaker & Meltzer, 2014). For adolescents, this number is somewhat reduced. Other factors in the child, for example, developmental difficulties like autism spectrum disorder (ASD), can substantially increase sleep problems (Won et al., 2019).

Although mechanisms of pathogenesis are unclear, most research suggest that a combination of factors including child, parent, family, and other variables is important. Temperamental difficulties are also a risk factor. Treatments have to do with helping parents of younger children establish better sleep patterns. Behavioral methods may help significantly (Reid et al., 2009). Most of this literature has focused on young children and there has been less work on older children and adolescents as well as those with special needs (Buckley et al., 2020; Durand, 2014; Meltzer & Mindell, 2014). For younger children, behavioral treatments are very effective. These include unmodified or graduated extinction (total or phased-out parental attention after lights out); this can be difficult for parents to do.

Helping parents understand good bedtime practices like using the bed only for sleep and the use of calming bedtime routines is important. Parents should be reassured that behavioral interventions have not been associated with negative outcomes (Baroni & Anders, 2018; Meltzer & Mindell, 2014; Taylor & Roane, 2010). Having phones, TVs, computers, etc., outside the bedroom is also helpful.

The addition of medications should be considered only after behavioral approaches have been attempted. There are no Food and Drug Administration (FDA)-approved medications for pediatric insomnia. Medications may be used at times of stress or illness (see Baroni & Anders, 2018). Many of the agents used have potential for “paradoxical” reactions (i.e.,
making the child more agitated). Melatonin is frequently used given its efficacy and relatively few side effects. Typical doses range from 1 to 3 mg (see Baroni & Anders, 2018). Other medications like clonidine or guanfacine are sometimes used particularly for children who have attention-deficit hyperactivity disorder (ADHD) (see Chapter 10), in particular, given how frequently these children have insomnia (Owens & Moturi, 2009). There are more risks with these agents. Although some of the antihistamines such as diphenhydramine are frequently used by pediatricians, there are limited data to support their efficacy, and these agents also have some important side effects.

Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a well-known but frequently unrecognized condition and should be considered in any child where snoring is reported. Overall, it has a prevalence of 1%-5% but becomes much more common in children who are obese or who have medical problems and habitual snoring (Marcus et al., 2012). Parents may not report snoring unless they are specifically asked. Even in the absence of OSA, snoring may have some of its features and consequences (Brockmann et al., 2012).

In addition to chronic snoring, the clinical features of OSA include labored breathing as well as gasping or choking during sleep. Apnea (breathing pauses) may be present and observed by parents. OSA can be associated with nocturnal enuresis (see Chapter 19). Unlike adults, excessive sleepiness in the daytime is less frequent in children. However, children are at risk for a number of other behavioral problems (Marcus et al., 2012; Mindell & Owens, 2015).

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