Sleep and Its Disorders in Children

Timothy F. Hoban, MD


Semin Neurol. 2004;24(3) 

In This Article

Sleeplessness in Infants and Younger Children

Nighttime waking is considered to be normal for young infants, influenced in part by the necessity of nighttime feedings for most babies until 5 or 6 months of age.[10] Although some infants begin to "settle" and sleep through the night as early as 3 months of age, some degree of brief nighttime waking is normal even during later infancy. Infants between 9 and 24 months of age woke on average twice nightly during actigraphic monitoring, although many returned independently to sleep without parental intervention or signaling of distress.[11] There exists no clearly defined threshold age beyond which excessive night waking is automatically considered abnormal. Instead, parental perception largely governs whether a child's nighttime waking is considered to be a problem. It is estimated that up to one-third of toddlers and preschoolers awaken at night to a degree considered worrisome by parents.[12]

A substantial number of predisposing or contributory influences have been identified with respect to night waking in infants, toddlers, and preschoolers. Major influences include:

Persistent Nighttime Feedings. In most healthy infants over 6 months of age, nighttime feeding is more likely to represent a learned behavior than a biological necessity. This is typically a self-limited behavior that subsides spontaneously as an infant matures. In situations where persistent nocturnal feedings significantly disrupt the quality and continuity of nighttime sleep, structured schedules for gradually reducing the quantity and frequency of nighttime feedings are usually highly effective.[12,13]

Separation Issues. Beginning after ~9 months of age, many infants experience distress when separated from their parents or caregivers. Although separation anxiety is considered a normal element of early childhood development, it can also precipitate significant distress at bedtime or during nighttime waking. This is typically self-limited and subsides with advancing age. Use of transitional objects such as blankets or stuffed animals may assist children in mastering separation responses that disrupt sleep.[14]

Temperament. There exists limited evidence that intrinsic aspects of child temperament, especially the ability to self-soothe, may substantially affect sleep during early childhood. Several studies have reported an association between "difficult" temperaments and disrupted nighttime sleep in young children.[15,16] In addition, lower sensory thresholds have been identified in infants with night waking compared with those without.[17] When a child's temperament contributes to a problem with sleeplessness, it is the author's experience that treatment is seldom successful unless this influence is identified and addressed as part of the overall treatment program.

Cosleeping. In the United States, some degree of cosleeping has been noted in about half of families with young children, with considerable variability of prevalence among different racial and socioeconomic groups.[14,18] In many parts of the world, however, cosleeping is considered the norm for infants and young children. Several clinical studies have suggested that cosleeping is associated with increased risk of night waking for young children, although the frequency of sleep disruption and degree to which night waking is considered problematic by families varies considerably among different ethnic groups.[18,19] Several PSG-based studies have also reported increased arousals and awakenings during the sleep of infants sleeping with their mothers compared with nights when sleeping alone.[20,21]

Bedtime resistance is usually seen in conjunction with excessive nighttime waking, although it may occasionally occur as an isolated problem. Bedtime resistance encompasses a broad variety of child behaviors that occur at or near bedtime. It often takes the form of "curtain calls," where a child may repeatedly leave the room, sometimes with requests for water, complaints of being unable to fall asleep, or attempts to engage the parent or spend more time out of bed in other activities. Bedtime resistance may also incorporate significant degrees of agitation such as protracted crying or oppositional behavior, resulting in significant distress for both child and parent. Such problems with settling to sleep are common in young children, affecting ~20% of 1- to 3-year-olds and ~10% of 4½-year-olds.[22]

Although the same associated influences already discussed with respect to night waking may also influence bedtime resistance, several other factors more directly impact bedtime struggles:

Bedtime Routines and Environment. Consistent, well-structured routines leading to bedtime aid children in transitioning from their daytime level of activity and alertness to a quiet, relaxed state more conducive to sleep onset. Conversely, irregular schedule or highly stimulating prebedtime activities often tend to disrupt sleep onset.[23] In a similar fashion, a quiet sleep environment that is dark or only dimly lit will for most children tend to promote faster and more comfortable sleep onset.

Fears and Anxieties. Childhood fears are common, but for most children they are a mild and self-limited problem. Bedtime is a common venue for childhood fears and anxieties, which may be either specific (e.g., robbers, monsters, darkness) or ill-defined. In most instances, bedtime fears can be addressed with gentle reassurance or use of a night-light.

Other Extrinsic Influences That Interfere With Settling at Bedtime. Many chronic medical conditions may be associated with difficulty settling, particularly neurological conditions such as cerebral palsy, autism, and other developmental disabilities.[24] Many commonly used medications, including stimulants and some anticonvulsants, are known to cause insomnia in at least some children. Acute febrile illnesses such as otitis media will often cause short-term disruption of sleep onset or continuity. Finally, extrinsic psychosocial stressors may have the potential to cause either acute or chronic sleep disruption.[12]

Sleep-onset association disorder is a condition affecting primarily infants and young children in which sleep onset becomes dependent on an environment or circumstance that cannot be independently recreated by the child without assistance. Potentially problematic associations for infants include being rocked, nursed, or bottle-fed at sleep onset. For toddlers and preschoolers, requiring parental presence at sleep onset is a common association. Although providing the specific circumstance desired by the child is usually perceived by parents to improve sleep onset at bedtime, some children become so reliant on the associated circumstance that they are unable to fall asleep in its absence. As a result, affected children are unable to settle themselves following the brief physiological awakenings that are part of normal sleep. The child, reliant upon the parent to provide the circumstance necessary for transition back to sleep, will cry or otherwise signal the parent, leading to frequent problematic awakenings during the night.

Effective treatment of sleep-onset association disorder generally requires that the child learn a new set of sleep-associated habits that do not require parental presence or intervention for sleep onset.[12,13] Gradual introduction and progressive reinforcement of the desired sleep habits (see below) eases this process for both child and parent.


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