Chapter 12. Pediatric Sleep Medicine

Pediatric and adolescent sleep disorders are common and often disturbing to either the patient or the family. Sleep disorders can adversely impact physical and mental health. Nonrestorative sleep can hamper a child's ability to concentrate and control emotions and behavior. Sleep disorders vary among age groups, but most can occur with varying frequency at any age. Several disorders are typically seen only during the first 3 years of life, including colic, excessive nighttime feedings, and sleep-onset association disorder. A number of conditions are common during childhood but begin to improve as the child ages. The non-REM sleep parasomnias—including sleepwalking, confusional arousals, and night terrors—are the most common in this category. Nightmares are also common in childhood but can occur at any age.

The sleep-related breathing disorders include obstructive sleep apnea, central sleep apnea, central alveolar hypoventilation syndrome, and Cheyne-Stokes respirations. These disorders can occur at any age, although the treatment options vary by age (Table 12-1).

The most frequent sleep-related problem for children between ages 6 months and 3 years is difficulty going to sleep or staying asleep throughout the night.1 Multiple factors have been implicated in the occurrence of repetitive night waking and inability to fall asleep: infant temperament, nutrition, physical discomfort, mild allergy, and parental marital conflict.2,3

Sleep-Onset Association Disorder

Clinical Features

Complaints of sleep problems in the infant and young child usually come from the parents, not the child. Nighttime awakenings sometimes become worrisome to parents. However, most often the problems reflect certain established patterns of interaction between the parent and the child at time of sleep transition. Nighttime arousals are very common in all ages; however, older children and adults are usually unaware of these disruptions.

Causes/Pathogenesis

A parent may incorrectly conclude that nocturnal awakenings are abnormal, becoming involved in the sleep transition process. The child may become accustomed to parental intervention and become unable to make the transition back to sleep alone, creating a sleep problem or sleep-onset association disorder. The child becomes reliant on the parent to help complete the sleep transition regardless of the time of night.

Diagnosis and Treatment

Diagnosis is usually made with a careful history. Children with this disorder often rapidly respond to simple gradual behavioral interventions, which helps the child learn a new set of sleep-associated habits.4

Difficulties Learning to Sleep Alone

Clinical Features

Sleeping alone throughout the night without parental intervention is a learned process. All children wake up 5 to 8 times per night, at the end of each sleep cycle, but some children are able to put themselves back to sleep without parental awareness. Most infants are capable of learning this process from about 5 to 7 months of age.1

Diagnosis and Treatment

The key is to gradually withdraw the amount of parental involvement at sleep onset. The same parental behavior response is required for middle-of-the-night awakenings. Consistency is also of critical importance if a treatment plan is going to work, especially in conditioning the child to sleep throughout the night. If fear is affecting the progression of this process, it is important to effectively deal with child and/or parental anxiety. Fear can prevent sleep, and fear of safety for one's child can alter a planned behavioral intervention. In certain cases, it will be important to have parents problem solve about their child's fear and how to best accommodate the behavioral treatment plan.

Excessive Nighttime Feedings

Clinical Features

Studies have shown that an increase in nighttime awakenings among infants and toddlers may be related to nighttime feedings. Infants fed large quantities at night (8-32 oz) have been shown to have continued and frequent awakenings, ranging up to eight per night.4-7 Repeated awakenings for ingestion of fluid directly disrupt the functioning of circadian-modulated systems, which may cause further deleterious effects on sleep–wake stabilization.4,8,9

Diagnosis and Treatment

Diagnosis can be made from a characteristic history: multiple nighttime awakenings, return to sleep only with feeding, significant fluid intake during the night, and extremely wet diapers. Treatment consists of a gradual decrease in the frequency of feedings during the night.4 Frequent awakenings, three or more per night in a child over 6 months of age, may cause sleep fragmentation that is harmful to the child. As feedings are decreased and associated habits are eliminated over a couple of weeks, sleep consolidation usually promptly occurs.7

Limit Setting

Inability to set limits at bedtime can also lead to sleep deterioration. Typical bedtime struggles may consist of requests for water, stories, use of the bathroom, and adjustment of lights.4,7 A diagnosis of this sort can be made from the history. Through history-taking it may become clear that the parents are unable to enforce nighttime rules with enough consistency to keep the child in bed and quiet so that he or she falls asleep. Parents may have to learn to be firm in their limit setting, enforcing a regular bedtime ritual with an end-point. The child should also be kept in his or her bedroom with the use of a gate of some sort or closure of the door if necessary. Positive behavior modification, such as a sticker, star chart, or other prizes for staying in bed, may elicit a positive response.4

Fear

Fear and nightmares are also commonly seen in early childhood, as part of normal development. A truly anxious child at night should be handled in the same manner whether the child's fears were initially expressed during waking or sleep. Mild fears often respond to supportive firmness and a stable social setting. Positive reinforcement, with rewards for staying in bed, may help motivate the child. Treatment may also consist of sleep schedule correction, progressive relaxation,10 and progressive desensitization.11

Colic

Clinical Features

Colic is the most common medical condition that affects the sleep of young infants. It causes inconsolable fussiness and crying, typically in the late afternoon and evening. Although symptoms usually remit by 3 to 4 months of age, continuing sleep disturbances are common, secondary to altered sleep schedules and habitual patterns of parental responsiveness.7

Diagnosis and Treatment

Colic is diagnosed when there are unexplained spells of crying in healthy infants. Treatment mainly focuses around education and management strategies for helping parents cope with the stresses of caring for the infant.12

In the course of clinical practice many unusual nocturnal phenomena may be described by patients or parents. The correct diagnosis can usually be ascertained from the clinical history alone, but in some cases polysomnography may be necessary. Additional EEG leads should be used if a seizure disorder is suspected. Additional EMG leads can be useful in patients with movement disorders.

Nocturnal movement disorders are extremely common in the pediatric population. In some cases, these events are so common that they may be considered a normal component of childhood and are usually "outgrown."

Restless Legs Syndrome

Clinical Features

Restless legs syndrome (RLS) is a disorder composed of four principal diagnostic criteria:

1. Intense, irresistible desire to move limbs, usually with uncomfortable feeling in the limbs

2. Symptoms worsen with decreased activity

3. Symptoms improve with activity

4. Symptoms are typically worse at night13

Patients, especially young children may have difficulty describing the symptoms. Children may get into trouble at school or at home because they have difficulty sitting still. RLS is underdiagnosed or misdiagnosed because of these factors.

RLS may cause significant sleep disturbance, especially with sleep onset. Patients may describe the subjective symptoms of RLS in a number of ways including creepy, crawly, tingly, like worms or bugs crawling under the skin, painful, burning, aching, and electrical. They may have difficulty describing the symptoms. In children, these symptoms can easily be mistaken for "growing pains."

Restless legs syndrome may coexist with periodic limb movements disorder (PLMD, described below) but are not always seen together. A comparison of the two syndromes appears in Table 12-2.

Epidemiology

RLS has an age-adjusted prevalence of up to 10% of adults. It is less common in children and increases with increasing age. The symptom severity also typically worsens with increasing age. Primary RLS is a genetic disorder with an autosomal dominant pattern. Secondary RLS associated with a precipitating factor, is less common. Renal failure, iron deficiency, and diabetes may contribute to the restlessness. In children, growing pains may mimic or cause restless legs.

Evaluation

The laboratory evaluation of RLS includes serum ferritin, screening for uremia, and screening for diabetes. Low normal ferritin levels (20-60) may be associated with RLS and frequently respond to treatment with iron.14 Polysomnography is not indicated in the evaluation of RLS, unless there is suspicion of a concomitant sleep disorder.

Treatment

Dopamine agonist therapy is the mainstay of RLS treatment in adults. No agents have been FDA approved for treatment of RLS in children. Use of simple nonpharmacological therapies may be of some benefit, including teaching the child to visualize an activity or simply allowing the child to move the legs. Teachers should be informed of the condition and the fact that it is not a form of attention-deficit disorder should be reinforced. Symptoms may be caused by an underlying iron or vitamin deficiency, and supplementing with iron, vitamin B12, or folate (as indicated) may be sufficient to relieve symptoms in these specific cases. A potential treatment algorithm is outlined in Figure 12-1.

Periodic Limb Movement Disorder

Clinical Features

Periodic limb movement disorder (PLMD) is "characterized by periodic episodes of repetitive and highly stereotyped limb movements that occur during sleep."15 While these movements usually occur in the legs, they can also occur in the arms. There is usually extension of the toe and flexion of the ankle, knee, and hip. Most patients are not aware of the movements. The sleep disruption associated with the movements can lead to insomnia or daytime somnolence. There is a repetitive increase in EMG activity (most often measured over the anterior tibialis muscle) lasting 0.5 to 5 seconds. The movement can be synchronous or asynchronous with the other leg or only involve one extremity. Both legs (and even the arms) should be monitored if PLMD is suspected. The movements are between 5 and 90 seconds apart. Most of the time, the movements occur every 20 to 40 seconds. Four or more consecutive movements are needed to count them as periodic limb movements (PLMs). The PLM index is the total number of PLMs divided by the total hours of sleep. A PLM index over 5 is considered abnormal. Often, PLMs are associated with arousals. A PLM-arousal index may also be noted on the sleep study interpretation. While many assume that the higher the PLM-arousal index, the more likely one is to suffer from daytime sleepiness, this has not been proven.16

Individuals with RLS, narcolepsy, and obstructive sleep apnea often have PLMs on a polysomnogram. While all patients with PLMD and most patients with RLS have periodic limb movements on a sleep study, only the RLS patients have the daytime annoying sensations in their limbs that improve with movement. Use of caffeine, neuroleptics, alcohol, monoamine oxidase inhibitors, or tricyclic antidepressants can cause periodic limb movements. Withdrawal of benzodiazepines, barbiturates, and certain hypnotics can cause or aggravate PLMS. PLMs are reportedly rare in children but increase in prevalence with age. PLMs may be seen in patients who are asymptomatic from them. Inadequate sleep habits, psychophysiologic insomnia, and other causes of daytime tiredness need to be considered and treated before placing a patient on medication for PLMs.

There are a few conditions that mimic PLMs. Sleep starts or hypnic jerks are frequently mentioned by patients. These occur in drowsiness, may be associated with a feeling of falling, and do not recur repetitively throughout sleep. Seizures can cause nighttime kicking movements but may also cause nocturnal enuresis, morning musculoskeletal soreness, or bleeding from oral laceration. An expanded additional 16-lead EEG on the polysomnogram is invaluable in identifying these individuals. Many people with sleep apnea have PLMs that disappear with initiation of effective treatment of the obstructive sleep apnea including surgery or continuous positive airway pressure (CPAP).

Rhythmic Movement Disorder

Clinical Features

Rhythmic movement disorder (RMD) "comprises a group of stereotyped, repetitive movements involving large muscles, usually of the head and neck; the movements typically occur immediately prior to sleep onset and are sustained into light sleep" (ICSD (15)). This can manifest as repetitive head banging, leg banging or body rolling. The movements typically start during drowsiness. Movements typically occur at a frequency of 0.5 to 2 times per second. While very common in normal infants, it is sometimes associated with a static encephalopathy, autism, or psychopathology in older children and adults. It is thought to have a self-soothing effect for some individuals. It appears to be more common in males. The noise from the movements can be disturbing to family members. While injuries, even serious injury such as subdural hematoma, are is possible, they are not common. It is very important to have the technologist accurately document what was seen at the time this occurs in the sleep laboratory. Continuous video monitoring usually easily confirms the diagnosis.

The differential diagnoses includes nocturnal seizures, masturbation, bruxism, and PLMD. Nocturnal seizures can usually be diagnosed by concomitant extra 16 channel EEG and review of the video. Masturbation has been mistaken for RMD. Bruxism and PLMD are usually easily distinguished on the sleep study. Gasping respirations from sleep apnea can cause rhythmic movements.

Nocturnal Bruxism

Clinical Features

Nocturnal bruxism is "a stereotypical movement disorder characterized by grinding or clenching of the teeth during sleep."15 This often leads to abnormal destruction of the surface of teeth, which may first be noticed by a dentist. It often causes headaches or jaw and facial pain. Its prevalence has been estimated at 5% to 20% or even higher.17 It is not uncommon in patients with a static encephalopathy.18 It occurs equally among males and females. Most people with bruxism are of normal intelligence. While a link has been questioned with anxiety and psychosocial stress, psychological problems are not more common in patients with bruxism. There is a familial tendency toward bruxism. Temporal mandibular joint dysfunction and malocclusion are sometimes accredited as being underlying causes or results of bruxism. There is no guarantee that correction of these abnormalities will cure bruxism in an individual. It can occur in all stages of sleep and is often disturbing to family members. Rhythmic muscle artifact is usually noted on most electrodes placed on the head.

The only significant differential diagnosis is a seizure disorder. Seizure disorders can cause masticatory movements in some individuals. Usually, there is additional history to lead to this diagnosis.

REM Sleep Behavior Disorder

Clinical Features

REM sleep behavior disorder (RBD) is characterized "by the intermittent loss of REM sleep electromyographic atonia and by the appearance of elaborate motor activity associated with dream mentation."15 The patient physically acts out a dream, leading to a variety of movements and actions. Episodes can be violent. It is more common in males. Although it can be seen at any age, it is most prevalent in the sixth and seventh decades, occurring more frequently in patients with Parkinson disease. REM sleep behavior disorder is uncommon in childhood but may be seen in young patients with narcolepsy. The polysomnogram shows episodes of sustained increased muscle tone in REM sleep instead of the decreased tone normally seen at this time (Figure 12-2). The polysomnogram should be preformed with continuous time-locked video. The video may show movements including punching and guttural utterances. If carefully awakened during an episode, the patient can often recall the content of the dream and a reason for the movements can sometimes be ascertained. There is often an increase in NREM periodic limb movements and REM density.

A careful general medical and neurological history is necessary. Tricyclic antidepressants and other anticholinergic medications may lead to RBD symptoms. There are also reports of transient RBD symptoms following hypnotic or alcohol withdrawal. The differential includes nocturnal seizures. Concomitant 16 channel-EEG can be useful in this situation. Another REM-related parasomnia, the nightmare, is sometimes confused with RBD. A nightmare is a frightening dream that often awakens the sleeper. Rarely, striking out can be part of a nightmare. RBD patients tend to be more explosive and usually do not awaken with the frightening aspect so common in a true nightmare. The differential also includes other NREM parasomnias including sleepwalking, confusional arousals, and sleep terrors (Table 12-3).

Sleep Terrors

Clinical Features

Sleep terrors are "characterized by a sudden arousal from slow-wave sleep with a piercing scream or cry, accompanied by autonomic and behavioral manifestations of intense fear."15 There are various autonomic phenomena present including tachycardia, mydriasis, diaphoresis, and flushing. Patients often sit up in bed and scream inconsolably. The facial expression is one of fear. The patient is very difficult to awaken. Once awakened, the person often seems confused. While a dream may be recalled, it is often fragmented and usually makes no sense. The patient is amnestic for the event. It is usually seen between ages 4 and 12 years of age, occurring in approximately 3% of children, but in rare cases may persist into adulthood. Like most NREM parasomnias, it usually disappears in adolescence. It is seen more commonly in males. Other family members may have NREM parasomnias.19 Sleep terrors begin in slow-wave sleep, usually in the first third of the night, but can happen anytime during the night.

The differential includes nightmares, confusional arousals, and epileptic seizures. When people awaken from nightmares, they are usually clear of mind and often can remember a dream with some detail. While some children can remember an image when awakened from a sleep terror, there is no frightening story such as with a nightmare. Nightmares are more common in the last third of the night, where REM sleep is more concentrated. There are usually fewer autonomic phenomena in a nightmare. If there is a partial arousal during slow-wave sleep, the person often seems stuck in a confused state without the fear seen in sleep terrors. This is called a confusional arousal. These people do not have the autonomic phenomena represented in sleep terrors. Epileptic seizures can present with a cry and the patient can be confused afterward. Ictal fear can be seen in certain epileptic syndromes. Most epileptics do not have seizures solely in sleep. Focal dystonic posturing or tonic–clonic activity points to a seizure as the likely diagnosis. Sometimes, continuous video-EEG monitoring is needed to distinguish a night terror from a nocturnal seizure.

Confusional Arousals

Clinical Features

Confusional arousals "consist of confusion during and following arousals from sleep, usually from deep sleep in the first part of the night."15 Patients may not respond, or may respond inappropriately, and are usually amnestic for the event. Confusional arousals usually arise in the first third of the night from slow-wave sleep. They are sometimes associated with incontinence. Typical of many NREM parasomnias, it is common in young children and it usually disappears with adolescence. While usually seen in children, it can be seen in adults when there is interference with awakening. Examples include sleep deprivation, metabolic encephalopathies, and use of medications that suppress the central nervous system. It is seen equally in both sexes. There is a familial predisposition to NREM parasomnias.

The differential includes sleep terrors, sleepwalking, and nocturnal seizures. Sleep terrors are associated with a frightful scream and more autonomic phenomena such as tachycardia, tachypnea, diaphoresis, and flushing. Sleepwalking is very similar to confusional arousals, except that people do get up and walk with sleepwalking. Most epileptics with nocturnal seizures also have diurnal seizures. Sometimes video-EEG monitoring is needed to distinguish nocturnal seizures from parasomnias.

Treatment

Reassurance for the patient and the patient's family is the most important component of care. In rare cases pharmacotherapy may be necessary. It is recommended that children with confusional arousals and sleepwalking may be safer not using a bunk bed.

Nocturnal Epilepsy

Clinical Features

Epilepsy is "a disorder characterized by an intermittent, sudden discharge of cerebral neuronal activity."15 There has been a growing interest in the relationship between sleep and epilepsy.20 Almost any seizure type can occur during sleep. In some epileptic syndromes seizures occur primarily during sleep (eg, benign epilepsy with central-temporal spikes or Rolandic epilepsy). The manifestation of the seizure depends on its anatomic origin. Generalized tonic–clonic seizures are associated with loss of awareness, tonic flexion and then extension, a forced expiratory "cry," and then clonic rhythmic jerking of the extremities. Focal (partial) seizures may or may not be associated with alteration of consciousness but are associated with unilateral sensory or motor phenomena. Automatisms consisting of repetitive picking movements or lip smacking may be seen. Seizures may start focally and then secondarily generalize (Figure 12-3). Sleep deprivation, noncompliance with antiepileptic medication, fever, and alcohol can contribute to breakthrough seizures. Epilepsy can be idiopathic or symptomatic of an underlying discernable brain lesion. The lesions could be a tumor, stroke, brain dysgenesis, hippocampal sclerosis, or due to posttraumatic changes. The EEG may show generalized, bilateral, synchronous spike-and-wave activity or generalized polyspike activity in patients with generalized seizures. The EEG often shows focal, regional epileptiform activity including spikes or sharp waves and focal slowing of background activity in patients with focal (partial) seizures. Focal epileptiform activity is more common in NREM sleep and suppressed in REM sleep. Epileptiform activity is much more common in sleep than wakefulness in children with Rolandic epilepsy. A diurnal EEG may be all that is needed to confirm the diagnosis. An EEG after sleep deprivation or overnight continuous video-EEG may be needed in more complicated cases. Sleep deprivation from other sleep disorders such as sleep apnea has been shown to worsen seizures in some patients.

The differential includes nocturnal paroxysmal dystonia, sleepwalking, rhythmic movement disorder, and REM behavior disorder. Nocturnal paroxysmal dystonia occurs in a short form (15-60 seconds) and a longer form (up to 60 minutes). It is characterized by repeated stereotypical dyskinetic episodes of ballismus or choreoathetosis often associated with vocalizations in NREM sleep.21 Sleepwalking, rhythmic movement disorder, and REM behavior disorder are not associated with epileptiform activity.

Narcolepsy

Clinical Features

Narcolepsy is a disorder of excessive sleepiness with a loss of control of the boundaries between sleep and wakefulness. The classic tetrad of symptoms (see Table 12-4) defining narcolepsy includes (1) excessive daytime sleepiness, (2) cataplexy, (3) sleep paralysis, and (4) hypnapompic or hypnagogic hallucinations.15 A minority of patients, between 10% and 15%, will actually have the entire tetrad of symptoms. Excessive sleepiness is the most common symptom. Sleep attacks, sudden and unpredictable episodes of severe sleepiness or sleep, are less common but can result in serious accidents and injury.

Cataplexy is a loss of muscular tone elicited by emotion, including laughing, excitement, anger, fear, and so forth. Cataplexy occurs in 76% to 80% of narcoleptic patients. The degree of weakness is variable, but weakness at the knees is the most common complaint. Extraocular muscles are typically spared, though blurred vision may occur. The episodes of weakness typically last a few seconds to greater than 30 minutes.

Sleep paralysis is the sudden onset of paralysis at sleep onset or at awakening. Patients are awake and conscious during the event. These episodes are of variable duration but typically last between several seconds and 10 minutes. Patients are able to move following any tactile stimuli. Sleep paralysis occurs in approximately 50% to 80% of narcoleptics.

Hypnogogic (sleep onset) and/or hypnopompic (awakening) hallucinations are typically bizarre or frightening dreams. The dreams consist primarily of visual hallucinations but in rare cases may include vestibular symptoms, auditory hallucinations, and a sense of levitation. These hallucinations occur in approximately 67% of narcoleptic patients (Table 12-4).

Nocturnal sleep disruption is common with repeated awakenings and frightening dreams. Patients are typically light sleepers despite being very sleepy during the day. REM behavior disorder is more common in narcoleptics than the general population.

Epidemiology

Narcolepsy occurs in approximately 1 in 2000 persons and peaks in the second decade of life. Subtle symptoms may be present much earlier. Parents often refer the child with narcolepsy as having been a "sleepyhead" as a young child. There is no significant gender difference for narcolepsy but there is a significant ethnic difference, with the disorder occurring more frequently in Japan. Monozygotic twins are discordant for narcolepsy. Eighty-six percent of narcoleptics with definite cataplexy have HLA DQB1-0602 on chromosome 6, but greater than 99% of patients with these haplotypes are normal. Orexin or hypocretin may also be involved in narcolepsy.22

Treatment

Several treatment options are available—see Table 12-5. Treatment of the excessive sleepiness is vital to improve daytime function and school performance. Modafinil (Provigil) is a pro-alerting drug that is FDA approved for the treatment of narcolepsy in adults and can dramatically improve daytime sleepiness. If modafinil proves ineffective, traditional stimulants such as methylphenidate and dextroamphetamine may also be of benefit. Xyrem is also FDA approved for cataplexy and narcolepsy in adults. In an off-label use, tricyclic antidepressants are also quite effective for cataplexy.

Circadian Rhythm Sleep Disorders

For optimal sleep and alertness, desired sleep time and wake times should be synchronized with the timing of the endogenous alertness promoting circadian rhythm. Misalignment between the circadian timing system and the 24-hour physical environment or work and social schedules can result in symptoms of insomnia and excessive daytime sleepiness. Circadian rhythm sleep disorders arise when the physical environment is altered relative to the internal circadian timing system, such as in jet lag and shift work, or when the timing of endogenous circadian rhythms is altered, such as in circadian rhythm sleep phase disorders. The latter is thought to occur predominantly because of chronic alterations in the circadian clock or its entrainment mechanisms (Figure 12-4). This chapter focuses on this second group of disorders.

Delayed Sleep Phase Syndrome

Clinical Features

Delayed sleep phase syndrome (DSPS) is characterized by bedtimes and wake times that are usually delayed 3 to 6 hours relative to desired or socially acceptable sleep/wake times. The patient typically cannot fall asleep before 2 to 6 AM and has difficulty waking up earlier than 10 to 1 PM.23,24 Attempts to advance the sleep times are frequently unsuccessful. Patients with DSPS often report feeling most alert in the evening and most sleepy in the early morning.25 In general, individuals with DSPS seek treatment or are brought in for treatment because enforced socially acceptable bedtimes and wake-up times result in insomnia, excessive sleepiness, and functional impairments, particularly during the morning hours.23

Clinical Epidemiology

DSPS is probably the most common of the primary circadian rhythm sleep disorders.26 The prevalence of DSPS among adolescents and young adults is 7% to 16%.23,27 It is a relatively common cause of the presenting symptom of insomnia in this age group.24

Alcohol and excessive caffeine may be used to self-treat in order to cope with symptoms of insomnia and excessive sleepiness, which in turn, may exacerbate the underlying circadian rhythm sleep disorder.

There is a family history present in approximately 40% of individuals with DSPS. The DSPS phenotype occurs as an autosomal dominant trait.28

Diagnostic Evaluation

The diagnosis of DSPS relies largely on the clinical history. However, diagnostic studies such as actigraphy and sleep diaries can be very useful to confirm the delayed sleep phase pattern. Recordings of sleep diaries and actigraphy over a period of at least 2 weeks demonstrate delayed sleep onset and sleep offset, with sleep onsets typically delayed until 2 to 6 AM and wake-up times in the late morning or early afternoon. Daily work or school schedules may result in earlier than desired wake time during weekdays, but a delay in bedtime and wake-up time is almost always seen during weekends and while on vacation. Polysomnographic (PSG) parameters of sleep architecture, when performed at the natural delayed sleep times, are essentially normal for age. However, if a conventional bedtime and wake-up time is scheduled, PSG recording will show prolonged sleep latency and decreased total sleep time.

Clinical Management

Approaches aimed at resetting circadian rhythms include chronotherapy and timed bright light therapy. Chronotherapy is a treatment in which sleep times are progressively delayed by approximately 3 hours per day until the desired earlier bedtime schedule is achieved.29 Although effective, the length and repeated nature of treatment and need for adherence to restrictive social and professional schedules limit practicality in the clinical setting. However, in adolescents, in whom behavioral factors often contribute to the delayed sleep phase, chronotherapy in conjunction with enforcement of regular sleep and wake times are important components of the clinical management.

Exposure to bright light for 1 to 2 hours in the morning results in an advance of the phase of circadian rhythms, whereas evening light exposure causes phase delays. Therefore, bright light exposure during the early morning hours and avoidance of bright light in the evening have been shown to be effective treatments for DSPS.30 Following 2 weeks of exposure to 2 hours of bright light of 2500 lux each morning and restricted evening light, individuals with DSPS showed earlier sleep times and reported improved morning alertness level. However, many patients, particularly those who are severely delayed, find it difficult to awaken earlier for the 1 to 2 hours of bright light therapy. Despite the potential utility of bright light therapy, the necessary timing, intensity, and duration of treatment are not known. Exposure to broad spectrum light of 2000 to 10,000 lux for approximately 1 to 2 hours is generally recommended for use in clinical practice.

Pediatric Obstructive Sleep Apnea

Epidemiology

The prevalence of pediatric obstructive sleep apnea (OSA) is estimated at 2% to 4% for children between the ages of 2 and 18.35,36 Obstructive apnea is very uncommon in normal children. In the past, obstructive sleep apnea was primarily seen in patients with significant adenotonsillar hypertrophy or neurological impairment.37 More recently, pediatric sleep apnea has been associated with the obesity epidemic in children.

The symptoms of obstructive sleep apnea in children differ from those seen in adults. Although daytime sleepiness and fatigue are reported in children, behavioral problems, hyperactivity, and neurocognitive deficits are much more common in children with sleep apnea compared to normal controls.38

Diagnosis

Pediatric OSA can be confirmed with polysomnography. The severity of OSA has been defined by use of AHI criteria alone. There are inherent problems with such an approach, most notably that there are substantial differences in how different sleep laboratories define respiratory events. This problem becomes more pronounced in the pediatric population. The criteria are different than adults, with an apnea index of >1/hr considered abnormal.

In children, a cessation of airflow of any duration (usually 2 or more respiratory cycles) is considered an apnea when the event is obstructive.35-39 Of note, the respiratory rate in children (20-30/min) is greater than in adults (12-15/min). The obstructive apnea hypopnea index (AHI) >1 is considered abnormal in children as opposed to 5 in adults (Figure 12-5). There is usually a mild decrease in the arterial oxygen desaturation.

The significance of central apnea in older children is less certain than in infants. Most do not consider central apneas following sighs (big breaths) to be abnormal. Some central apnea is probably normal in children, especially during REM sleep. In one study, up to 30% of normal children had central apneas. Central apneas longer than 20 seconds or those of any length associated with arterial oxygen desaturation below 90% are often considered abnormal, although a few such events have been noted in normal children.38 Therefore, most would recommend observation unless the events are frequent and the arterial oxygen desaturations severe.

There is a shortage of sleep laboratories that can accommodate children. Other potential screening techniques have not proved successful thus far. Therefore, in a child with behavioral problems, hyperactivity, or daytime sleepiness, a polysomnogram should be considered, especially if obesity, tonsillar and/or adenoidal hypertrophy, or other upper airway anatomic abnormalities are present.

Treatment

In contrast to adults, the treatment of choice for the majority of pediatric OSA cases is adenotonsillectomy. There are some specific groups who are at increased risk for postoperative morbidity: children <3 years of age; severe OSA; and those with underlying medical disorders. Weight loss and nasal CPAP are also used in pediatric OSA for those cases who do not improve after adenotonsillectomy or are not surgical candidates. Craniofacial surgeries are also an option in selected children with anatomic abnormalities.