Sleep Disorders in Children
Katherine Finn Davis
Judith A. Owens
Sleep is one of the primary activities of the growing child; by the time children have reached their third birthday, they will have spent more time sleeping than in all waking activities combined. Although there appears to be considerable individual variability in sleep duration (and presumably, in sleep needs), this substantial sleep requirement continues into the adolescent years, suggesting that sleep plays a vital biological role in cognitive, physical, and psychological development across childhood. In the context of this increased need for sleep, the potential impact of insufficient and/or poor quality sleep in the pediatric population is considerable. Children with sleep disturbances have been noted to exhibit poor conduct, hyperactivity, short attention spans, and poor academic performance. Furthermore, sleep disturbances in children are common with approximately 25% of the pediatric population experiencing some type of sleep disturbance or problem, ranging from inadequate sleep hygiene to obstructive sleep apnea syndrome (1).
A basic understanding of the major normal developmental changes in sleep structure (architecture) and sleep patterns and behaviors across childhood is necessary to fully appreciate the etiology and impact of sleep disorders on the child and adolescent. First, as children mature, their sleep needs gradually decline. Second, the distribution of sleep stages changes; there is a striking decrease both in the amount of REM sleep and in the preponderance of slow wave sleep from birth (50% of sleep) through early childhood into adulthood (2). Third, the nocturnal alternating or “ultradian” rhythm of non-REM and REM sleep gradually lengthens from about 50 minutes in infancy to the adult duration of 90 to 110 minutes. Finally, the homeostatic sleep drive builds up more slowly as children develop, allowing them to remain awake for longer periods without a daytime sleep opportunity (nap).
DEVELOPMENTAL SLEEP DIFFERENCES
Newborns (0 to 2 months)
Newborns generally sleep about 16 to 20 hours per 24 hours, which is acquired in 1- to 4-hour sleep periods followed by awake periods lasting 1 to 2 hours. This sleep is equally distributed during the nocturnal and diurnal periods. During this early developmental stage, sleep-wake periods are chiefly dependent on hunger and satiety, as circadian sleep-wake rhythms are not fully developed until 2 to 4 months, and environmental cues play a relatively small role. For example, bottle-fed newborns typically sleep longer periods than breast-fed infants (3 to 5 vs. 2 to 3 hours). Newborns have three basic sleep states as defined by electroencephalogram (EEG) patterns, eye movements, and muscle tone: active (“REM-like”; 50% of sleep), quiet (“non-REM-like”), and “indeterminate” sleep (with features of both). Unlike older
children and adults, newborns enter sleep through active or “REM-like” sleep. Because this active sleep state is behaviorally characterized by grimaces, smiles, sucking, twitching, and jerking, it is sometimes interpreted by parents as disrupted or restless sleep.
children and adults, newborns enter sleep through active or “REM-like” sleep. Because this active sleep state is behaviorally characterized by grimaces, smiles, sucking, twitching, and jerking, it is sometimes interpreted by parents as disrupted or restless sleep.
Most sleep issues that are perceived as “problematic” at this age actually represent a discrepancy between these developmentally appropriate sleep behaviors and parental expectations regarding sleep patterns. Newborns that are noted to be excessively fussy and difficult to console may have causal medical issues such as gastroesophageal reflux, colic, or formula intolerance due to food allergies (e.g., milk protein).
Infants (2 to 12 months)
Infants typically sleep between 9 to 12 hours at night and between 2 to 4.5 hours during the day (comprised of one to four naps, each lasting 30 minutes to 2 hours). It should be noted that the greatest individual variability in sleep amounts appears to occur in the first year of life (3). The longest nighttime sleep period during the first 3 months is approximately 3 to 4 hours long, and lengthens to 6 to 8 hours by 4 to 6 months of age. In terms of sleep architecture, the amount of active/REM sleep declines, and three distinct stages of non-REM sleep (stage N1, N2, and slow wave sleep) emerge by around 6 months. The ultradian sleep cycle lasts about 50 minutes, and each cycle frequently ends with a brief arousal (approximately 7 to 10 times per night at 2 months to 4 to 6 times at 12 months).
Many physical, cognitive, and social developmental issues can influence sleep during this time. Two key developmental “milestones” of infant sleep are referred to as sleep consolidation and sleep regulation. Sleep consolidation is defined as the ability to sleep for a continuous period of time concentrated during the nocturnal period, which is supplemented in young children by shorter periods of diurnal sleep (naps). This is commonly referred to as “sleeping through the night.” Infants first develop the ability to consolidate sleep in the first 8 to 12 weeks of life; by 9 months of age, about 70% to 80% of infants have achieved this milestone. Sleep regulation, or the ability of the infant to “self soothe,” begins to develop in the first 3 months and is defined as the ability to master the sleep-wake transition at sleep onset, as well as to return to sleep independently after normal night arousals/awakenings. In addition, other developmental milestones including the emergence of gross motor skills such as rolling over and crawling may temporarily interfere with sleep. Cognitively, the emergence of object permanence and thus of separation anxiety in the latter part of the first year can cause increased bedtime resistance and problematic night awakenings.
Both transient and chronic sleep problems are common in infancy; roughly 25% to 50% of 6- to 12-month-olds and 30% of 1-year-olds have problematic night awakenings and approximately 50% of 1-year-olds have sleep onset or settling difficulties. Identified risk factors for the persistence of sleep problems include “difficult” temperament, maternal depression, family stress, and medical conditions in the infant. Common sleep disorders in infants include the behavioral insomnias of childhood, particularly the sleep onset association type, and sleep-related rhythmic movements (head banging, body rolling, and body rocking).
Toddlers (12 months to 3 years)
Toddlers sleep approximately 12 to 13 hours in a 24-hour period. Napping continues to be an important source of sleep; most toddlers abandon the morning nap by 18 months, but continue to nap in the afternoon (usually for 1.5 to 3.5 hours).
Many developmental changes are occurring in toddlers, and sleep issues at this stage often reflect these changes. For example, children are developing gross motor skills that allow them increased mobility to climb out of their crib or bed
during night, and thus, the timing of the transition from crib to bed typically becomes an important concern between 2 to 3 years of age. Cognitively, a toddler’s vast learning ability and achievement of new skills may interfere with nighttime settling. Fortunately, the child’s developing understanding of cause and effect allows basic behavioral interventions to be useful. Development of imagination and fantasy may lead to nighttime fears, while social and emotional development of autonomy and independence can lead to increased bedtime resistance. Separation anxiety peaks at about 18 to 24 months, and may lead to increased night awakenings as symbolic meaning of objects develops; bedtime rituals and transitional objects (e.g., pacifier, doll, blanket) are commonly used strategies to reduce these separation problems. Finally, regression in sleep behavior is a typical response to stress at this age, and may increase the likelihood of “reactive” co-sleeping (i.e., in response to a sleep problem, in contrast to “lifestyle” co-sleeping or the “family bed”).
during night, and thus, the timing of the transition from crib to bed typically becomes an important concern between 2 to 3 years of age. Cognitively, a toddler’s vast learning ability and achievement of new skills may interfere with nighttime settling. Fortunately, the child’s developing understanding of cause and effect allows basic behavioral interventions to be useful. Development of imagination and fantasy may lead to nighttime fears, while social and emotional development of autonomy and independence can lead to increased bedtime resistance. Separation anxiety peaks at about 18 to 24 months, and may lead to increased night awakenings as symbolic meaning of objects develops; bedtime rituals and transitional objects (e.g., pacifier, doll, blanket) are commonly used strategies to reduce these separation problems. Finally, regression in sleep behavior is a typical response to stress at this age, and may increase the likelihood of “reactive” co-sleeping (i.e., in response to a sleep problem, in contrast to “lifestyle” co-sleeping or the “family bed”).
Sleep problems are very common, occurring in about 25% to 30% of toddlers; bedtime resistance is reported in 10% 15% of toddlers and night awakenings in 15% to 20% (4). Common sleep disorders in toddlers include the behavioral insomnias of childhood (sleep onset association and limit-setting types) characterized by bedtime resistance and/or night awakenings and sleep-related rhythmic movements (head banging, body rolling, and body rocking).
Preschoolers (3 to 5 years)
Preschoolers need approximately 11 to 12 hours of sleep over 24-hour period. Naps are still important, as 92% of 3-year-olds, 57% of 4-year-olds, and 27% of 5-year-olds nap. However, nap duration decreases and naps are eventually given up completely by 5 years.
Routine is very important for preschoolers and to normalize sleep-wake patterns, including a consistent bedtime and wake time along with a regular daytime routine. Developing language and cognitive skills at this age give the child the ability to express their needs and may lead to increased limit-setting problems and bedtime struggles. Developing imagination and fantasy can lead to nighttime fears. A so-called “second-wind” phenomenon is often seen in preschoolers and is due to the late-day circadian mediated peak in alertness that occurs in all humans, but may be amplified or delayed in some children, and often results in bedtime resistance.
Data suggest that 15% to 30% of preschoolers experience night awakenings and difficulties falling asleep, sometimes co-existing in the same child, and that if sleep problems are not addressed, they tend to become chronic. Common sleep disorders in preschoolers include nighttime fears, nightmares, behavioral insomnias of childhood (sleep onset association and limit-setting types), obstructive sleep apnea, and partial arousal parasomnias (sleepwalking and sleep terrors).
School-aged Children (6 to 12 years)
School-aged children need approximately 10 to 11 hours of sleep in a 24-hour period. School-aged children normally have a high physiologic level of alertness and naps are typically very infrequent at this age; thus, any reports of daytime sleepiness are highly suggestive of inadequate and/or disrupted nocturnal sleep.
During this period of growth and development, children begin to assume more responsibility for their own self-care and therefore it is a critical time to instill healthy sleep habits. Common sleep issues are irregular sleep-wake schedules (discrepancy between school and non-school night bedtimes and wake times) and increased caffeine use. Extracurricular activities, peer relationships, and media/electronics (e.g., television, computers, video games) are increasingly important and compete for sleep time. Nighttime worries may increase as the child becomes more cognitively aware of real dangers (e.g., fires, burglars) and have also been associated with increased pressure to excel academically.
Until recently, sleep problems in middle childhood were considered rare, but current studies report an overall prevalence of parent-reported sleep problems in as many as a third of these children. Common sleep disorders in school-aged children include nightmares, partial arousal parasomnias, obstructive sleep apnea, behaviorally induced insufficient sleep, and inadequate sleep hygiene.
Adolescents (12 to 18 years)
Experimental data suggest that adolescents generally require about 9 to 9.25 hours of sleep; however, a number of survey studies suggest that many average only 7 to 7.25 hours. Adolescence is a period of dramatic biologically driven changes in sleep (5). At onset of puberty, adolescents develop an up to 2-hour physiologically based phase delay (later sleep onset and wake times) as a result of pubertal/hormonal influences in circadian sleep-wake cycles and melatonin secretion. This often results in a substantial discrepancy between the circadian-based adolescent preference for both a late sleep onset time and wake time and the demands of the average adolescent’s schedule, which may require awakening for school at 5 or 6 AM, as start times of junior and high schools are typically earlier than those of elementary schools.
These physiologic changes are accompanied by increased social, occupational, and academic demands, which also tend to delay sleep onset. Parents are also less likely to supervise bedtimes and enforce adequate sleep hygiene as adolescents mature. The result is often chronic insufficient sleep and the accumulation of a substantial sleep debt. In addition, there is an increasing discrepancy between weekday and weekend bedtime and wake time schedules, with “weekend oversleep” in an attempt to make up for restricted sleep during the week. All of these factors contribute to a high level of daytime sleepiness in this age group with related impairments in mood, attention, memory, behavioral control, and academic performance.
In addition to the widespread problem of insufficient sleep, the prevalence of sleep problems is as high as 20% and certain groups, such as those with chronic medical conditions or psychological problems, may be at higher risk. Important sleep disorders in adolescence include behaviorally induced insufficient sleep, inadequate sleep hygiene, insomnia, delayed sleep phase disorder, restless legs syndrome/periodic limb movement disorder, and narcolepsy.
IMPACT OF SLEEP DISORDERS
Adequate sleep is necessary for optimal functioning; consequently, sleep disorders in children have a pervasive impact on many aspects of health and development. Health outcomes related to inadequate sleep range from an increase in accidental injuries to possible harmful effects on the cardiovascular, immune, and metabolic systems. A child’s physical, emotional, cognitive, and social development are negatively affected as well. Children with daytime sleepiness related to sleep disorders can experience significant mood dysfunction and poor academic and sports performance. Children who are sleep deprived have also been reported to exhibit poor impulse control, impaired verbal and cognitive abilities, decreased creativity, and short attention spans. Furthermore, children classified as “poor sleepers” by teachers and parents are more likely to have behavioral and mood problems.
In general, younger children respond differently to inadequate sleep than do older children and adolescents. An overtired toddler or preschooler may manifest paradoxical hyperactivity, irritability, and impulsivity while older children display typical signs and symptoms of daytime sleepiness similar to adults such as yawning, low energy, and drowsiness. However, all children of all ages who experience
inadequate or disrupted sleep as a result of sleep disorders can exhibit the following nonspecific signs and symptoms:
inadequate or disrupted sleep as a result of sleep disorders can exhibit the following nonspecific signs and symptoms:
Mood changes and negative sense of well-being
Excessive daytime sleepiness with drowsiness and unscheduled naps
Fatigue and somatic complaints
Cognitive impairment and poor school performance related to excessive sleepiness, negative mood, and fatigue.
SPECIFIC SLEEP DISORDERS
Those sleep disorders that are either unique to or found largely in infancy and childhood, or that have a substantially different clinical presentation and/or etiology in children compared to adults are discussed below. Inadequate sleep hygiene and behaviorally induced insufficient sleep as common contributing factors are also discussed.
Inadequate Sleep Hygiene and Insufficient Sleep Syndrome
Inadequate sleep hygiene and insufficient sleep syndrome are two of the most common causes of sleep problems and excessive daytime sleepiness (EDS), either as primary sleep disorders or in combination with other sleep disorders. Inadequate sleep hygiene includes both sleep-related behaviors that increase arousal and delay or interrupt sleep (e.g., stimulant use, light and noise during the night) (6) and those that interfere with sleep organization (e.g., napping close to bedtime). Insufficient sleep syndrome occurs when the total sleep amount does not meet the sleep need. These sleep problems are important to identify because they frequently compound the clinical impact of other sleep disorders and are generally amenable to behavioral interventions.
Studies suggest a high prevalence of inadequate sleep hygiene and/or insufficient sleep syndrome in children and adolescents (7). Likely causes of inadequate sleep hygiene are knowledge deficits in both the parent and child on good sleep hygiene practices and consequences of poor sleep, lack of appropriate role modeling of good sleep habits, and lack of parental supervision at bedtime. Likely causes of insufficient sleep syndrome are numerous including excessive time demands (e.g., after school jobs and sports, homework, social activities) that delay bedtime, electronic media in the bedroom, and early school start times. See Table 14.1 for sleep tips for children and adolescents.
Behavioral Insomnia of Childhood
Behavioral insomnia of childhood is characterized by bedtime resistance and/or difficulty falling asleep, problems staying asleep, or both that are usually a result of either inappropriate sleep-onset associations or inadequate caregiver limit setting.
Limit-Setting Type
A sleep disorder in which parents or caregivers are unable or unwilling to establish appropriate sleep behaviors and enforce bedtime limits.
Clinical Presentation.
The associated signs and symptoms are similar to those resulting from other sleep disorders, which result in inadequate sleep. Children often exhibit the following:
Noncompliant behavior, including verbal protests in response to parental requests to get ready for bed (e.g., change into pajamas, brush teeth)
Bedtime resistance, including stalling or refusal to go to bed or requiring a parent to be present at bedtime
TABLE 14.1 Sleep Tips for Children and Adolescents
For both children and adolescents:
Sleep schedule. Keep a consistent bedtime and wake time. Staying up a little later or getting up a little late (up to 1 hour) is OK on nonschool nights. Ensure that bedtime is set early enough to be able to get adequate sleep.
Evening activities. The hour before bedtime should be a settle down time. Avoid stimulating activities such as sports, video games, and exciting television shows.
Late night activities. Televisions, computers, phones, and other electronics should be banned from the bedroom at bedtime. These are distractions from sleep and their light exposure can make it difficult to fall asleep.
Snack. Avoid heavy meals close to bedtime, but a light snack will help avoid the problem of going to bed hungry.
Bedroom. The bedroom should be a soothing place for sleep. It should be a comfortable temperature (∽68°F to 72°F), quiet, and dark (with night lights OK for younger children).
Bedtime routine. Have about 30 minutes of “down time” each night before bedtime. A routine of brushing teeth, bathing, reading a book, or listening to relaxing music is helpful to signal the body that it is time for sleep.
Caffeine. Avoid caffeine during the afternoon and evening hours, although it is best to avoid it entirely.
Naps. Naps are usually not needed once a child reaches grade school. Naps should be avoided late in the day or for a long of a period of time as this can interfere with the ability to fall asleep at the regular bedtime. An occasional nap for ≤45 minutes in the early afternoon is reasonable.
Exercise. Try to get some exercise outdoors each day as it can help you fall asleep more easily at night, but avoid exercising too close to bedtime.
Especially for adolescents:
Sunlight. Exposure to morning sunlight can help keep the body on a regular sleep-wake rhythm.
Weekends. Staying up late and sleeping in on weekends will make it harder to resume a normal bedtime and wake-up time during the week.
Alcohol, drugs, and smoking. All of these make it harder to sleep.
Sleeping medicine. Using sleeping pills, melatonin, or other over-the-counter sleep medicines can be harmful and does not treat the underlying sleep problem.
Driving drowsy. Don’t do it! Teenagers are at the highest risk for falling asleep while driving. Accidents can happen in the afternoon as often as during the night.
“Curtain calls,” which are typified by repeated demands for parental attention (e.g., another story, drink of water, trip to bathroom) after bedtime
Delayed sleep onset, usually 30 minutes or more after scheduled bedtime
Frequent night wakings resulting from lack of limit setting or sleep associations that have developed (e.g., parent present at bedtime)
Daytime behavior problems due to insufficient sleep.
Epidemiology.
Limit-setting type is most common in preschool and early schoolaged children. The prevalence in toddlers and preschoolers is 10% to 30% and 15% in school-aged children (8). Limit setting may co-exist with sleep-onset association disorder. Without intervention, it often becomes a chronic problem.
Diagnostic Evaluation.
Evaluation requires a medical history and physical examination. Although the medical history and exam are usually benign, an evaluation is
necessary, as children with contributory acute or chronic medical conditions are prone to bedtime resistance. Diagnostic tests are not indicated.
necessary, as children with contributory acute or chronic medical conditions are prone to bedtime resistance. Diagnostic tests are not indicated.
A comprehensive evaluation should also include:
Review medication use for potential contributory factors.
Developmental history: Children with developmental delays or sensory integration issues may have more problems with self-soothing at bedtime.
Family history: Assess parenting skills and limit-setting abilities.
Behavioral assessment: A history of more global behavior issues such as oppositional defiant disorder (ODD), attention-deficit/hyperactivity disorder (ADHD), and noncompliance may be present.
Diagnosis.
Diagnostic criteria include difficulty initiating or maintaining sleep manifested by stalling and/or refusal behavior at bedtime or following night awakenings as a result of inadequate or inappropriate limit setting by the caregiver(s).
Differential Diagnosis.
Limit setting type should be distinguished from:
Inappropriate sleep schedules: Involves inconsistent bedtimes and wake times, late napping (after 4 PM), significant discrepancy between weekday and weekend sleep schedules.
Delayed sleep phase syndrome: Difficulty falling asleep occurs only when the individual attempts to go to bed earlier than their “preferred” (later) bedtime.
Nighttime fears: Usually suspected when anxiety is seen as a large component of bedtime resistance. Bedtime resistance disappears when the parents remain with the child at bedtime and sleep onset is not delayed.
Transient insomnia: Usually seen in a previously normally sleeping child in response to illness, stress, unfamiliar sleeping environment, etc.
Periodic limb movements/restless legs: Can result in difficulty falling asleep or fragmented sleep, but usually there is a history of increased symptoms at rest and/or restless sleep and nocturnal leg kicks.
Management.
Successful management should include three components: establishment of appropriate sleep habits, development of a sleep schedule that matches the child’s circadian rhythm, and appropriate and consistent limit-setting by parents. It should be noted that behavioral interventions for both bedtime resistance and night awakenings in young children have considerable empirical support. Strategies include (9):
Establishing a consistent bedtime that matches the child’s natural sleep onset tendency.
Instituting a regular bedtime routine involving a 20- to 45-minute set routine involving quiet activities (e.g., bath, pajamas, reading).
Ignoring any complaints or protests at bedtime.
Checking on child briefly (if upset or crying).
Returning the child to bed or room if necessary.
Provision of a transitional object, such as a doll, blanket, or stuffed animal.
Maintenance of good sleep hygiene practices.
Evaluation of daytime sleep habits, such as inappropriate napping (after 4 PM).
Reinforcement of good behavior, including star charts and small rewards for achieving goals such as staying in bed all night.
Follow-up.
Any toddler or young child with limit-setting sleep disorder who does not respond to simple behavioral management tactics or are causing family discord should be referred to a mental health professional for evaluation and treatment. If there is a concern regarding the presence of an underlying sleep disorder or medical problem, appropriate referral is necessary. Collaboration with a behavioral therapist in complex situations is recommended.
Sleep-Onset Association Type
A sleep disorder characterized by the child learning to fall asleep only with particular circumstances or associations present and, consequently, not developing the ability to “self-soothe.”
Clinical Presentation.
Associated signs and symptoms are similar to those resulting from other sleep disorders, which result in inadequate sleep. The presenting issue is usually one of prolonged night waking resulting in insufficient sleep (for both parent and child). Clinical features include:
The child will fall asleep only under certain conditions or in the presence of specific sleep associations (e.g., feeding, rocking, lights on), which are readily available at bedtime.
When the child experiences the brief arousal that normally occurs at the end of each ultradian sleep cycle (every 60 to 90 minutes) or awakens for other reasons, he is not able to get back to sleep (“self-soothe”) unless those same conditions are present.
The child “signals” the parent by crying (or coming into the parents’ bedroom if the child is not confined to a crib) until the necessary associations are provided.
