Pediatric Sleep Disorders

Introduction

Sleep is one of the most important activities that growing children engage in. By age 3 years, children will have spent more time sleeping than any other activity and will have spent more than half of their lives asleep. As they get older, they continue to require a substantial amount of sleep into their adolescent years. This significant sleep requirement is vital for cognitive, physical, and psychologic development across childhood. Given the high level of sleep requirement in this age range, the impact of insufficient sleep and/or poor-quality sleep can be considerable. This insufficient or poor-quality sleep can manifest as attention deficit disorders with short easily disrupted attention spans, emotional lability/mood changes, psychiatric illness, hyperactivity, behavioral/conduct disorders, and poor academic performance. Up to 25% of the pediatric population experiences a form of sleep disturbance, regardless of the disorder type.

There are major developmental changes in sleep architecture, sleep patterns, and sleep behavior throughout childhood. As children mature, they slowly attain adult-type sleep patterns, including less daytime sleep/naps and shorter sleep duration. Rapid eye movement (REM) sleep decreases from 50% of total sleep time to the normal adult pattern of 25% of sleep time and slow-wave sleep, which is highest in early childhood, drops off dramatically after puberty, and continues to decline thereafter throughout the life span.

This chapter endeavors to discuss normal sleep patterns in children at different age ranges and then discusses sleep pathology, specifically focusing on common pediatric sleep disorders. We will then discuss the interconnection between psychiatric disorders and sleep disorders. Finally we will have a short discussion on specific psychiatric disorders and their effects on sleep.

Normal Sleep Development

It is important to recognize that sleep is an active process, which involves cycling of physiologic diverse stages throughout the night, and the specific stages are dependent on the particular stages in development.

Newborns (0–2 Months)

Newborns generally sleep approximately 16–20 h per day. The newborns sleep cycle is much shorter than the adult sleep cycle such that newborns sleep in 1- to 4-h periods followed by wake periods of 1–2 h. This sleep pattern does not follow any nocturnal or diurnal patterns, which explains why newborns awaken frequently throughout the night. At this time the circadian sleep-wake rhythms are not yet developed and do not emerge until around 2–4 months of age; therefore, environmental cues play no significant role in sleep onset or maintenance at this developmental stage. Newborn awakenings are dependent on hunger and satiety such that formula-fed newborns tend to wake up less frequently than breast-fed newborns. On average, formula-fed newborns awaken every 3–5 h, whereas breast-fed newborns awaken every 2–3 h. This is likely due to the higher caloric density of formula compared with breast milk. As such, formula-fed newborns feel fuller longer than breast-fed newborns.

Unlike older children and adults, newborns enter into REM sleep immediately on falling asleep. They exhibit mainly REM sleep (active sleep) and non-REM sleep (quiet sleep) only on electroencephalogram (EEG). Sleep architecture patterns, such as deep sleep/slow-wave sleep, do not develop until later in development. During active REM sleep, newborns may exhibit grimaces, smiles, sucking, twitching, and jerking. Parents may sometimes interpret this as a disrupted or abnormal sleep pattern or may interpret it as not sleeping; however, this is a normal and expected sleep pattern.

At this developmental age, most sleep concerns are generally parental perceptions of problematic sleep patterns, which are actually a discrepancy between developmentally appropriate sleep behaviors and parental expectations of “normal” sleep. Other sleep concerns in newborns at this developmental age may include excessive fussiness and difficultly consoling due to medical issues such as colic, formula intolerance due to food allergies, metabolic disorders, seizures, and gastroesophageal reflux disorders.

Infants (2–12 Months)

Infants generally sleep approximately 9–12 h at night and 2–5 h in total during the day (1–4 naps). There can be a significant individual variability in sleep amount during this developmental stage. At 2–3 months of age, infants sleep in 3- to 4 -h periods, whereas by 4–6 months, infants lengthen their sleep periods to 6–8 h uninterrupted. Therefore by 6 months of age, some infants may be able to sleep 8 h through the night. During this developmental stage, active/REM sleep declines in total duration and quiet/non-REM sleep begins to separate into three distinct stages of non-REM sleep, specifically stages N1, N2, and N3 (also known as slow-wave sleep). During this period, infants are expected to reach multiple developmental milestones, including physical, cognitive, and social milestones. They are also expected to reach to specific sleep development milestones—sleep consolidation and sleep regulation. Sleep consolidation involves the ability to sleep for a continuous period generally concentrated during the night. In other words, the children should begin “sleeping through the night.” By 9 months of age, roughly 70%–80% of infants will have achieved this sleep development milestone. Sleep regulation involves the ability of the infant to “self-soothe” as they fall asleep at the beginning of the night and in the middle of the night if they awaken. In other words, infants at this age should master the ability to fall asleep and returned to sleep independently after normal night arousal/awakenings.

It is important to note that other developmental milestones, which are being acquired during this period, may temporarily disrupt sleep, but these disruptions should not persist. For instance, as the infant learns to roll over and crawl (gross motor developmental milestones), they may spend some of their sleep/nap time enjoying their emerging independence. Furthermore, cognitive developmental milestones, including development of object permanence can lead to separation anxiety and eventually develop into bedtime resistance, sleep onset/settling difficulties, and problematic nighttime awakenings. Up to 25%–50% of infants at this developmental stage experience transient and/or chronic sleep problems. Risk factors for these sleep problems persisting and becoming chronic include “difficult” temperament, maternal depression, family stress, and medical conditions being experienced by the infant. Clear bedtime routines and use of transitional objects such as pacifiers and blankets can reduce these separation concerns. Other sleep disorders noted at this developmental age include sleep-onset association disorder and rhythmic movement disorders (discussed in the following).

Toddlers (12 Months–3 Years)

Toddlers generally sleep about 12–13 h in a 24-h period. Napping remains an important factor in daily sleep at this developmental stage. Morning naps tend to drop off usually around age 18 months; however, the afternoon naps remain usually lasting about 1.5–3.5 h. Developmentally, toddlers are progressing quite drastically. At this age, they have significantly increased mobility so that they can climb out of their crib at night. As such, transitioning from the crib to the bed may be critical at this age. At this stage, toddlers are increasing their language and cognitive skills dramatically daily, and this may interfere with nighttime bedtime routines when they endeavor to oppose the usual bedtime routines. Fortunately at this age, children are beginning to understand consequences, as well as cause and effect, and thus behavioral interventions can be beneficial at this stage. On the other hand, toddlers begin to develop imagination and fantasy, which can lead to bedtime fears, as well as the development of autonomy and independence that can all result in increased bedtime resistance. Separation anxiety can also adversely affect sleep. Therefore, transitional objects can remain very important to reduce anxiety. At this time, parents frequently resort to cosleeping to reduce the bedtime resistance. Unfortunately this may sometimes lead to regression in sleep behavior and sleep-onset association insomnia.

Sleep problems at this stage occur in 25%–30% of toddlers with bedtime resistance and nighttime awakenings accounting for most of the problems. At this developmental stage, behavioral insomnias of childhood such as sleep-onset association disorder and limit-setting sleep disorder are common. In addition, rhythmic movement disorders such as head banging, body rolling, and body rocking can be prevalent.

Preschoolers (3–5 Years)

Preschoolers generally require 11–12 h of sleep in a 24-h period. Napping time persists in about 92% of children at age 3 years and drops to 27% by age 5 years. The duration and frequency of napping after age 5 years gradually peters off until napping is given up completely. By this age, sleep architecture during nighttime sleep will begin to follow a more adult pattern but still have a high proportion of both slow-wave sleep and REM sleep. Given the rapid cognitive, physical, and social development at this age, children are able to express their needs more clearly, which may lead to worsening in limit-setting problems and bedtime resistance. Therefore, it is important to maintain a set bedtime routine with consistent sleep and wake times and is imperative to normalize sleep-wake patterns. Continued development of imagination and fantasy can worsen fears and anxiety around bedtime.

Preschoolers experience sleep disorders in about 15%–30% of the population. This is a critical time to address sleep problems and sleep disorders, as habits are developing at this age and sleep difficulty may become chronic. Common sleep disorders among preschoolers include nighttime fears, nightmares, behavioral insomnias, including sleep-onset association disorder and limit-setting sleep disorder, obstructive sleep apnea (OSA)/sleep-disordered breathing, and partial arousal parasomnias, which include sleepwalking and sleep terrors (see the following).

School-Aged Children (6–12 Years)

School-aged children require about 10–11 h per 24-h period. By this age, their sleep architecture is almost identical to the distribution of sleep stages in adults. Naps are infrequent by this age, as school-aged children normally have a very high physiologic level of alertness. Therefore daytime sleepiness at this age is highly suggestive of sleep deprivation/disruption due to a sleep disorder. At this age, children are beginning to develop more autonomy and responsibility for their self-care. As a result, it is important to continue to instill healthy sleep habits at this developmental stage. Children are more likely to begin to use caffeine by way of sodas and other caffeinated drinks, and this can lead to a regular sleep-wake cycles. Furthermore, extracurricular activities, peer relationships, and media/electronics become increasingly important and begin to compete for sleep time. Nighttime fears may begin to escalate at this age, as children become more cognitively aware of real dangers such as fires, burglary, and death. The increased pressure to perform well academically can also impair normal sleep. Interestingly, based on teacher and parental surveys, children who are classified as “poor sleepers” tend to exhibit more behavioral and mood problems overall.

Sleep problems may be considered fairly rare at this age group, and common sleep disorders include nightmares, anxiety-related sleep-onset delay, partial arousal parasomnias, OSA, sleep-disordered breathing, behaviorally induced insufficient sleep syndrome, and poor sleep hygiene.

Adolescents (12–18 Years)

Adolescents generally require about 9–9.25 h of sleep nightly; however, studies show that adolescents generally get only 7 h of sleep in a 24-h period. This sleep deprivation may exacerbate the emotional difficulties frequently experienced at this age. Furthermore, slow-wave sleep decreases by around 40% between ages 10 and 20 years. During this developmental stage, adolescents are undergoing significant biologic changes during sleep. For instance, during puberty, there is a significant increase in secretion of hormones, including growth hormone, and these hormonal changes are dependent on circadian rhythms. In addition, adolescents undergo a physiologic circadian phase delay of at least 2 h such that they begin to develop later sleep-onset times and later wake times. Unfortunately, extensive academic, extracurricular, social, and occupational demands can require adolescents not only to sleep late but also to awake early, which tends to be in opposition to their naturally delayed circadian rhythm. This can lead to significant chronic insufficient sleep and poor sleep hygiene. Because of increased autonomy and decreased adult supervision, adolescents tend to engage in “weekend oversleep” to make up for the significant sleep debt they accumulate during the week. As such, they develop an increasing discrepancy between weekday and weekend bedtime and wake time schedules. In addition, adolescents have a physiologic predisposition to develop decreased daytime alertness in mid- to late puberty. Overall, these factors lead to increased daytime sleepiness, poor nighttime sleep, which ultimately leads to impaired mood, creativity, attention, impulse control, memory, and academic performance.

There is roughly a 20% prevalence of sleep problems in this age group, with those experiencing chronic medical and/or psychiatric disorders at the highest risk. Common sleep disorders at this stage include behaviorally induced insufficient sleep syndrome, inadequate sleep hygiene, insomnia, delayed sleep phase syndrome (DSPS), restless leg syndrome (RLS), and narcolepsy.

Pediatric Sleep Disorders

It is important to note that younger children with sleep disorders respond differently to chronic sleep disruption compared with older children and adolescents. A sleepy toddler or preschooler exhibits paradoxic hyperactivity, irritability, and impulsivity, whereas sleepy older children exhibit signs and symptoms similar to that of adults with chronic sleep disruption such as low energy and drowsiness. Regardless, there are nonspecific signs and symptoms, which children of all ages manifest with chronic inadequate sleep:

mood changes
negative sense of well-being
excessive daytime sleepiness manifesting as drowsiness or unscheduled naps
fatigue
somatic complaints
cognitive impairment
poor school performance

This can lead to increased stress, abnormal sensation/reaction to pain, poor eating habits, among other adverse reactions. To be clear, no sleep disorder is confined to the pediatric age range; however, some sleep disorders occur primarily in childhood and may manifest differently in a nonpediatric population.

Clinical Evaluation

Accurate diagnoses and treatment of pediatric sleep disorders are dependent on a comprehensive clinical evaluation. This includes assessing both waking and sleeping behaviors. An initial assessment should include

a detailed sleep history
medical history
family history of sleep disorders
social history
psychologic/psychiatric assessment
developmental screening
physical examination

Age of onset, the associated circumstances, degree of debilitation, persistence/worsening, triggers, and ameliorating factors should be included in this assessment. In addition, usual sleep/wake habits, napping habits, bedtime/nighttime awakenings, and symptoms of daytime sleepiness and/or irritability should be documented. Duration of sleep periods, frequency, timing, sleep changes during weekends and vacations, stressors, and school performance should also be assessed. Sleep diaries and sleep habit questionnaires may also be beneficial. It is also important to assess symptoms of snoring, overnight gasping for air, episodes of stopped breathing, sleepwalking, sleep talking, and bed-wetting.

Common Pediatric Sleep Disorders During the First 3 Years of Life

Behavioral insomnia of childhood

Behavioral insomnia of childhood is defined as difficulty falling asleep, staying asleep, or both, which is a consequence of poor limit setting or inappropriate sleep-onset associations.

Limit-setting behavioral insomnia

This disorder is characterized by parents or caregivers who are unwilling or unable to institute appropriate sleep routines and enforce bedtime limits. Inability to set limits during bedtime routines can result in sleep deterioration. The child will constantly find reasons to lengthen the duration of the bedtime routine by making unnecessary excuses such as requests for a glass of water, more stories, use of the bathroom, and food. Parents will describe a child with noncompliant behavior who verbally protests parental requests, has bedtime resistance, repeatedly demands parental attention after bedtime, has delayed sleep onset usually over 30 min, has frequent nighttime awakenings, and has poor daytime function due to insufficient sleep. This disorder is common in preschool and early school-aged children. Prevalence is up to 30% of preschoolers and about 15% of school-aged children. Without intervention, it can become a chronic problem.

Diagnosis and treatment

Through extensive history taking, the diagnosis can easily be made. Medical history and physical examination are usually benign except for possible oppositional defiant disorder or attention-deficit hyperactivity disorder (ADHD). For children with limit-setting behavioral insomnia, it will be incumbent on the parents to learn to be firm with their limit setting by establishing a regular bedtime and ensuring the bedtime routines have a clear endpoint. Maintaining good sleep hygiene practices and daytime sleep habits such as avoiding naps is beneficial. Reinforcing good behavior with positive behavioral modification using stickers or star charts or other prizes may rapidly elicit the awaited response.

Sleep-onset association behavioral insomnia

In this disorder, the child learns to fall asleep only with specific associations, usually parents, and has an inability to self-soothe during nighttime awakenings without that specific association. This disorder is primarily stressful for the parents, and nighttime awakenings can be quite bothersome and disruptive to parental sleep. The disorder tends to be a reflection of the established patterns of interactions between the parent and child around the time of bedtime. The child becomes accustomed to parental intervention to enable them to fall asleep. As such the child becomes reliant on the parent to make the sleep transition successfully regardless of the time of the night. Using a commonly described analogy from leaders in the field, most adults fall asleep with a pillow and if they awaken in the middle of the night and find the pillow is gone, they will wake up and look for it. When the pillow is found, they can easily fall back to sleep. Based on this analogy, in the child’s eyes, the presence of the parent while falling asleep is equivalent to the pillow. Consequently, a child with sleep-onset association behavioral insomnia will wake up and look around for his or her “pillow” and will be unable to fall back to sleep until the pillow/parent is located. This can cause distress, leading to a full awakening and agonizing crying by the child until the parent appears. Once the parent returns to the room, the child is easily able to fall back to sleep. Sleep-onset association behavioral insomnia is primarily seen in infants and young children. Up to 50% of 6- to 12-month-olds, 30% of 1-year-olds, and 20% of toddlers exhibit symptoms of this disorder.

Diagnosis and treatment

Diagnosis is usually made through careful history taking. Medical history and physical examination are usually benign. There are multiple options for intervention that can be employed here. These include (1) extinction , which involves letting the child “cry it out” until they learn to self-soothe; (2) gradual extinction , which involves progressively ignoring the child for longer and longer periods until the child learns to self-soothe; and (3) fading of adult intervention , in which the parent positions themselves further and further away from the child at bedtime until eventually they are no longer in the room. Engaging in regular bedtime routines, avoiding prolonged daytime naps, and an introduction of other transitional objects such as blankets, dolls, and stuffed animals are important. Furthermore, a discontinuation of nighttime feedings is important to reduce the chances of a “learned hunger” nighttime habit. Children with sleep-onset association behavioral insomnia usually rapidly respond to simple gradual behavioral interventions, which helps the child to develop new sleep association habits that do not include the parent.

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