Charles A Pohl

By Charles A. Pohl, MD, and Amy Renwick, MD 

 Sleep problems such as frequent awakenings, sleep terrors, and sleepwalking are common in children and adolescents. Understanding sleep physiology and educating parents about sleep hygiene and other interventions can turn an unhealthy situation around. 

and screaming two hours after falling asleep. The child is difficult to fully awaken during these episodes, yet appears normal the following day. The concerned mother wants to know if the child is traumatized by his weekly visits with her estranged husband.

After returning from a family vacation at the beach, a 3-year-old begins to awaken three times a night for a glass of water. The parents ask if this behavior reflects a medical condition, such as diabetes or a bladder infection. If it doesn't, can they give the child a cold medicine to help her sleep?

 Teddy bears. Lullabies. Sweet dreams. We like to think of bedtime as a peaceful period and sleep as a refreshing rest. In reality, bedtime for many children and their parents is a stressful occasion, and a good night's sleep merely a sweet dream.

 A third or more of children and adolescents experience sleep problems, like those described in the two opening scenarios.

 Common complaints include bedtime refusal, frequent awakenings, daytime sleepiness, nightmares, and sleepwalking. These disturbances result in parental anxiety, frustration, and sleeplessness. Affected children may be irritable, less successful in school,

Sleep disturbances can thus have a far-reaching effect on the entire family. Parental interventions may unintentionally exacerbate the problem.

 To establish and preserve healthy sleep patterns, it is important for families and pediatricians to understand normal sleep physiology and common causes of disruptions. This article reviews developmentally appropriate sleep patterns in children and discusses common sleep disturbances, emphasizing a practical approach to management.

 The sleep-wake cycle and the physiologic patterns of sleep undergo developmental changes from infancy to adulthood. Newborns spend about 70% of their time sleeping; adults, only 25% to 30%. Infants require about 14 to 16 hours of sleep daily (Figure 1 in the print edition: Figure 1, from Ferber R, Kryger M: 

Principles and Practice of Sleep Medicine in the Child

. Philadelphia, WB Saunders Company, 1995, Used with permission from Elsevier Science).

 Daily sleep time decreases to about 13 hours by 2 years of age, 11 hours by 5 years, 10 hours by 10 years, and eight to nine hours during adolescence.

 Term newborns typically have four to six evenly distributed sleep-wake periods daily. Consolidation of daily sleep into the nighttime period usually begins by 6 weeks of age. Many infants start to sleep through the night by 4 to 6 months of age. Daytime sleep usually diminishes to three naps per day by 6 months, two naps per day between 6 and 12 months, one nap per day between 12 and 24 months, and no naps by 3 to 5 years. Including this information in routine health maintenance visits can promote good sleep routines as well as alleviate many parental anxieties.

 Two distinctive sleep states have been identified: non-rapid eye movement (NREM) and rapid eye movement (REM). These states, present in virtually all mammals and birds, are separated from one another by unique behavioral characteristics and by physiologic patterns on polysomnography.

 During NREM, brain activity slows, while muscle movement and thermoregulation are preserved. NREM sleep cycles predominate during the first third to half of nighttime sleep and are divided into four stages. Early sleep progresses through NREM stages 1 to 4 (Figure 2 in the print edition, from: Sheldon, SH, Spire J-P, Levy HB: Pediatric Sleep Medicine. Philadelphia, WB Saunders Company, 1992, Used with permission from Elsevier Science). In stage 1, the sleeper is drowsy and still somewhat responsive. By stages 3 and 4 (also called slow-wave sleep, delta-wave sleep, and deep sleep), it is very difficult to arouse the sleeper, who is quite confused if awakened. This physiologic pattern helps explain why sleep problems that take place during NREM stages 3 and 4, such as sleep terrors and sleepwalking, occur early in the night and are characterized by dramatic body movements with no awareness of the environment.

 REM, or active, sleep cycles predominate in the latter half to third of the night. The portion of total sleep that is REM sleep decreases with agefrom about 50% to 80% in infancy to 20% to 25% in adulthood.

 During the REM stage, muscle tone is inhibited in all but the ocular and respiratory systems, and thermoregulation is lost. The sleeper has episodic bursts of rapid eye movement (eyelids usually closed), irregular pulse, and tachypnea, while extremity muscles are usually motionless. Muscle twitches are occasionally observed during this sleep phase. Dreams are common.

 Partial awakenings, which are times when the sleeper enters a light sleep from a deeper sleep, are common in both children and adults. The sleeper may open his eyes but resumes a deeper sleep once he recognizes a familiar environment. These awakenings are especially common in children 6 to 12 months of age. To help keep sleep problems from developing, children should be encouraged to fall asleep in the familiar surroundings of their own crib or bed, and parents should be encouraged not to disturb their infant during partial awakenings.

 Children younger than 3 months of age experience three, rather than two, distinct stages of sleep: NREM, REM, and indeterminant sleep. This last phase is defined by physiologic changes on the sleep study inconsistent with the other two stages. Unlike the sleep composition of older children and adults, the sleep composition of infants predominantly consists of REM. At this age, sucking movements, facial twitches or grimaces, vocalizations, and stretching during REM sleep are common. Minimal body movement is noted during this stage.

 In addition to the makeup of a person's sleep architecture (awake-NREM-REM cycles), timing and structure of sleep depend on circadian rhythm over a 24-hour period. The biologic clock affects not only sleep but also hormonal secretion, core body temperature, and kidney function. Social and environmental cues are required to maintain a 24-hour sleep-wake cycle. In the absence of external input, the cycle is between 24.5 and 25 hours. Infants can become entrained to a 24-hour cycle by 2 months of age.

 Light's effect on the suprachiasmatic nucleus (SCN) of the hypothalamus appears to be the most important factor regulating or pacing the circadian system (Figure 3). Retinal photoreceptors relay information to the SCN when exposed to light. Studies have shown that light is capable of shifting the cycle by as long as two hours a day: Light exposure before sleep can delay sleep onset; light exposure toward the end of sleep can hasten awakening. Melatonin, normally secreted by the pineal gland at night, has an opposite effect.

 [Editors' note: For information on melatonin, see "

 Core body temperature fluctuates in a typical pattern during the sleep-wake cycle and appears to be important in regulating sleep (Figure 4, from: Richardson GS, Carskadon MA, Orav EJ: Circadian variation of sleep tendency in elderly and young subjects. 

 1982;5(Suppl 2):S82, and Kryger MH, Roth T, Dement WC: 

Principles and Practice of Sleep Medicine

). Philadelphia, WB Saunders Company, 1994.

 The temperature is lower during sleep periods such as nighttime and mid afternoon and higher during wakeful hours. Declining body temperature appears to facilitate sleep. If a person attempts to fall asleep during the "wrong" part of the cyclein the evening, for example, when body temperature is risingsleep is less likely to occur and, if it does, is more likely to be disrupted.

 Although the need for a good night's sleep is obvious, the biologic function of sleep is unknown. Studies suggest, however, that NREM sleep plays a role in restoration of somatic tissue. REM sleep, on the other hand, appears to be important in learning and memory processing as well as central nervous system restoration. Sleep also is thought to be important to the immune system. In adults, sleep is associated with changes in levels of circulating catecholamines and cytokines such as interleukin-6 and interleukin-2.

 In most cases, a careful history and physical examination can elicit the underlying sleep problem. Subsequent evaluation and management can be tailored to specific patient issues, based on the findings of the initial assessment.

 Obtain a detailed sleep history, in addition to a history of the patient's presenting complaint; the medical, developmental, and psychological history; and the family and social history. Questions should identify the patient's sleep-wake schedule, current sleep patterns, and associated nighttime and daytime symptoms. It also is important to ask about the child's sleep environment. A list of useful questions appears in Table 1.

How much time does the child spend in bed? How much of that time is she asleep? 

 What does she do in the hour before bedtime? Is there a consistent bedtime routine? 

 If the child has nighttime feedings, how many ounces does she consume? 

 What is the sleep environment like? (Ask about co-sleeping, noise, temperature.) 

 When does the problem occur relative to bedtime and relative to the time of actually falling asleep? 

 What does the child do? (Elicit a detailed description of the problem.) 

 Does she seem aware of what is happening? 

 When does the child wake up in the morning? Is she difficult to awaken? 

 Is the child sleepy during the day? Is school performance affected? 

 How much caffeine does the child consume (in coffee, tea, soda, chocolate)? 

 A diary of the child's sleep pattern and complaints can be a useful evaluation tool. It can give the pediatrician a better idea of the real extent of the problem, especially in families where the parents remember only two evenings: the child's worst night and the one just preceding the office visit. Videotaping any unusual events (such as abnormal breathing patterns or movements during sleep) also may be helpful during the initial evaluation.

 A general physical examination should be performed, but it is rarely helpful in patients whose history does not provide clues to organic or functional disease. Special attention should be paid to the airway and the nervous system. Observation of the child's behavior and parent-child interaction also is useful.

 In most cases, no additional investigation of the child's problem is necessary once a detailed history has been obtained and a physical examination performed. In cases where further investigation is warranted, studies and tests should be tailored to the child's clinical presentation. Polysomnography, which includes an electroencephalogram (EEG), electromyogram (EMG), and electro-oculogram (EOG) and sometimes additional monitors, is useful if a disorder such as nocturnal seizures, obstructive sleep apnea,

 Other studies to consider are a multichannel sleep study with a pH monitor, airway or pulmonary evaluation, neurologic tests, psychological testing, head imaging studies, toxicology screens, and cardiac studies. Any child being awakened by pain requires a thorough evaluation to rule out malignancy or serious systemic illness.

 Sleep interruption is common in the pediatric population and can impair quality of sleep for the child and parents alike. These disruptions, in turn, can affect the health, development, and quality of life of the child and parents. Sometimes, irregular sleep patterns result in potentially dangerous situations. The remainder of this article discusses specific causes of sleep disruptions (Table 2) and management strategies.

Causes of nighttime sleep disruptions in children 

Arousal disorders (sleep terrors and sleepwalking) 

Remember that cultural practices regarding sleep vary. If the child, parents, and family schedule are not disturbed by an unusual sleeping practice, there is little point in trying to adjust sleep habits.

 About 25% of children suffer from an arousal disorder, such as sleepwalking or sleep terrors.

 Arousal disorders occur during NREM stages 3 and 4 (slow-wave or deep sleep); as expected, parents report that the events occur in the first third to half of the child's sleep. These disorders can have dramatic symptoms (significant muscle movement, tachycardia, tachypnea, diaphoresis) and are characterized by, in addition to significant muscle movement, unresponsiveness to the environment and lack of remembrance of the episode upon awakening. Episodes are exacerbated by inadequate or disruptive sleep. Children with these disorders do not have daytime symptoms (such as daytime sleepiness) or polysomnographic abnormalities.

(somnambulism) is perhaps the most dangerous sleep disorder, with the potential for causing severe injury, even death. Risks include walking through glass, falling down stairs, and wandering into traffic or extreme weather. Sleepwalking begins in the preschool or school years. Episodes last up to 10 minutes, during which the sleepwalker may perform complicated tasks or urinate in inappropriate places without conscious awareness.

A sleeping child who suddenly screams and is found thrashing about and sweaty with dilated pupils is probably having 

, or pavor nocturnus. Attempts to comfort the child are unsuccessful, but after 10 minutes or so he (or she) returns to a calm sleep state. Sleep terrors usually begin after the age of 18 months. Although the child appears terrified, he will not recall a particular scary dream or even the episode itself.

 Arousal disorders may be distressing to witness, but they do not indicate any underlying psychopathology and rarely require any significant intervention other than parental education. These disorders begin to resolve as the child reaches adolescence. There is no need to try to awaken the child during an episode. Sleepwalkers can be led back to their beds. Parents should ensure the child's safety by preventing access to stairways and streets. In extreme situations, and if the sleep terrors or sleepwalking occur at a predictable time each night, parents can attempt to put an end to the sleep disturbance by waking the child 15 to 30 minutes before an event and then allowing him to resume sleep after several minutes.

 Improved sleep hygiene (Table 3), stress reduction, or a brief afternoon nap (an hour or less) may also help.

 Medications and psychotherapy are rarely indicated.

 Follow a consistent schedule for bedtime and wakening 

 Limit caffeine, especially after lunchtime 

 Schedule naps, if needed, early in the day (before 2 p.m.) 

 Turn the television off at least 30 minutes before bedtime 

 Avoid meals, exercise, or stimulating television shows near bedtime 

 Have the child empty his bladder just before going to bed 

 Make the sleeping environment quiet, dark, and not too hot or cold 

 Put the child in bed while he is still awake 

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Sleep problems are common in children and adolescents. Understanding sleep physiology and educating parents about sleep hygiene and other interventions can turn an unhealthy situation around.

Charles A Pohl

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