Pediatric Sleep Disorders 

Sleep disturbances in youth represent highly common phenomena that, in severe forms, can interfere with daily patient and family functioning. Interest in pediatric sleep problems continues to increase, yet further investigation is needed to develop empirically based detection and treatment of pediatric sleep disorders.

The consequences of untreated sleep problems may include significant emotional, behavioral, and cognitive dysfunction. The magnitude of these sequelae is inversely proportional to the child's overall ability to adapt and develop in spite of the sleep disturbance. Nevertheless, sleep regulation remains a critical part of health for youths. Elevated rates of sleep problems exist among children and adolescents with neurodevelopmental, nonpsychiatric medical conditions and psychiatric disorders.

Reciprocal relationships occur between sleep disorders and comorbid psychiatric disorders. For example, when a given child with recurrent depression has an exacerbation, sleep problems often increase simultaneously. On the other hand, disrupted and inadequate sleep alone can produce behavioral, affective, and cognitive dysfunction.

Neurobiologically, closely linked modulatory systems appear to regulate sleep, alertness, and attention span. This article focuses on the most prevalent sleep problems among youths that are typical and distinctly unique from adult sleep disorders. Night terrors, nightmares, and sleep apnea are covered only briefly because they are discussed in other articles.

This article uses classifications and definitions from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Text Revision (DSM-IV-TR) along with more operationally defined problems when appropriate.

Childhood sleep disorders are classified in the following three categories: dyssomnias, parasomnias, and medical-psychiatric disorders. Adolescents with substance use disorders represent a significant proportion of sleep-disordered youths.

Patients with dyssomnias present with difficulty initiating or maintaining sleep or with excessive daytime somnolence. The DSM-IV-TR defines dyssomnias as primary disturbances in the quantity, quality, or timing of sleep. These disorders are believed to be a consequence of central nervous system abnormalities that alter the sleep process.

Parasomnias result in disruption of an existing state of sleep. Arousals, partial arousals, and sleep-stage transition impositions define this category. An alternative definition of these phenomena describes deviated behavioral or physiological events that transpire during sleep, specific sleep stages, or sleep-wake transitions. Insomnia or excessive sleepiness is uncommon in parasomnias despite intrusion upon sleep. These are dyssomnia symptoms as noted above. Most parasomnias affect otherwise healthy youths and commonly subside over the course of adolescence. These disorders are typically viewed as transient developmental phenomena, although children with parasomnias were recently found to display higher rates of sleep-onset delay, night awakenings, bedtime resistance, and reduced sleep duration compared to a community control group.

Medical-psychiatric–associated sleep disorders comprise the neuropsychiatric conditions that typically include sleep disturbances. Attention deficit hyperactivity disorder (ADHD), gastroesophageal reflux disease (GERD), pervasive developmental disorders (PDD), mental retardation (MR), Down syndrome, Prader-Willi syndrome, Tourette disorder, nocturnal asthma, depressive disorders, anxiety disorders, mania, neuromuscular disorders, nocturnal seizures, Kleine-Levin syndrome, chronic fatigue syndrome, headaches, and blindness with associated sleep disorder are representative of this category of medical-psychiatric–associated sleep disorders.

Dyssomnias

Primary hypersomnia: Youths with primary hypersomnia have normal sleep efficiency, sleep/wake cycles, and sleep architecture. Patients with primary hypersomnia present with a normal variant sleep pattern except for longer sleep needs. It may be a lifelong pattern. No other identifiable cause exists for the excessive somnolence that continues for at least 4 weeks. Chronic mood disorders may also mimic chronic hypersomnia and are particularly important to exclude.

Primary or idiopathic insomnia: The pathogenesis of primary hypersomnia is poorly defined. Patients with primary or idiopathic insomnia may have a lifelong inability to initiate and maintain sleep with associated sequelae.

Sleep-state misperception: Youths with sleep-state misperception may have normal polysomnography. The pathology of sleep-state misperception is associated with an underestimate or misperception of the child's sleep duration, which results in the patient's mistaken belief of having experienced inadequate sleep.

Psycho-physiological insomnia: This disorder is related to psychological stressors that interfere with sleep onset or maintenance.

Narcolepsy: Rapid eye movement (REM) sleep mechanisms are dysregulated in youths with narcolepsy, but evidence also exists of nonrapid eye movement (NREM) and circadian sleep-wake cycle abnormalities. REM-associated sleep phenomena intrude into the awakened state. Sleep attacks (sleep), cataplexy (abrupt atonia precipitated by strong emotions), hypnagogic and hypnopompic hallucinations (experienced as dreamlike events immediately before sleep onset or upon awakening) are characteristic of narcolepsy. Excessive daytime somnolence leading to irresistible/involuntary sleep (sleep attacks) may occur. The role of the neuropeptide hypocretin (Orexin) and human leukocyte antigen (HLA)–DR2/DBQ1 as a genetic-neuroimmune interaction is being considered in current research on this issue. Narcolepsy is consistent with the polygenic model of development in most human cases.

Obstructive sleep apnea syndrome (OSAS): The pathophysiology of OSAS is poorly understood. Alterations exist in alveolar ventilation and oxygenation. OSAS is associated with adenotonsillar hypertrophy; however, most youths with adenotonsillar hypertrophy do not experience OSAS. Upper airway neuromotor dysfunction is possible in the initiation of OSAS.

Periodic limb movements in sleep (PLMS): PLMS is more prominent in NREM stage 1 and 2 sleep. PLMS is strongly associated with ADHD and restless legs syndrome (RLS) in the pediatric population. The response to dopaminergic agents and the association with ADHD suggest that PLSM may be a dopaminergic dysfunction. Characteristic movements may aid in further understanding of the pathology of PLMS. Repetitive flexion of lower extremities (more common) or upper extremities occurs in youths with PLMS with a 0.5- to 5-second duration occurring 5-90 seconds apart. Repetitive jerks are associated with frequent awakenings and daytime somnolence or insomnia. The pediatric population with PLMS often experiences inattention, overactivity, and mood lability due to associated sleep disruption/fragmentation. PLMS can occur without RLS.

RLS: The response to dopaminergic agents and the association to ADHD implicate that RLS is a dopaminergic dysfunction. Leg discomfort in patients with RLS is associated with a strong urge to move legs, and the relief with movement may ultimately reveal a pathophysiology similar to that of akathisia. Most patients with RLS have PLMS. The pediatric population with RLS often experiences inattention, overactivity, and mood lability due to associated sleep disruption/fragmentation.

Limit-setting sleep disorder: This is a parent-child transactional model with potentially numerous biopsychosocial variables that influence interactions. It is not simply a failure to set limits but has a more complex pathogenesis and ultimately pathophysiology. Children with limit-setting sleep disorder resist or refuse to go to bed at an appropriate time. Limit-setting sleep disorder may be related to underlying pathophysiology as observed in ADHD and other neurodevelopmental disorders or may be a combined medical-behavioral issue.

Insufficient sleep syndrome: This is a condition of chronic sleep deprivation without an underlying disease process. Youths with insufficient sleep syndrome may experience an increased need for sleep during puberty and adolescence. Insufficient sleep syndrome may represent a poor compensatory ability for sleep loss and includes failure to adequately synchronize sleep-wake behaviors and adapt to environmental demands, such as school. The patient with insufficient sleep syndrome attempts to decrease sleep debt incurred during the week by sleeping later on the weekends. They are unable to obtain sufficient sleep because of school, extracurricular, occupational, and other societal demands.

Circadian sleep disorders: A circadian clock/oscillator located in the suprachiasmatic nuclei of the anterior hypothalamus influences the wakefulness or alertness phase. A circadian clock potentiates alternate or diurnal phases of the sleep-wake cycle. A free-running human sleep-wake cycle is 25 hours; however, the cycle entrained by the environment results in a 24-hour cycle. Sleep and associated processes are at opposite phases or periods in patients with circadian sleep disorders. Circadian sleep disorders may represent a poor compensatory ability for sleep loss and includes failure to adequately synchronize sleep-wake behaviors and adapt to environmental demands, such as school. This disorder is frequently observed in adolescents with delayed sleep phase.

Parasomnias

Parasomnias are sleep-related phenomena disrupting normal sleep. Events can take place during sleep-wake transitions, arousal, or REM sleep. Sleep stages and other variables are related to pathogenesis.

Sleepwalking: Sleepwalking is described as partial arousal from sleep during slow-wave stages 3 and 4. It is most common during the initial third stage of the sleep period.

Bruxism (persistent grinding of the teeth): Bruxism is considered as a stereotyped movement disorder or rhythmic disorder. It is more frequent during the early part of sleep and may be related to stress and/or anxiety or dentition abnormalities. Bruxism is not limited to sleep but may also occur while the child is awake. Basal ganglia dysfunction has been hypothesized.

Nightmares: Nightmares appear to be related to the same etiology as other anxiety-related experiences. They occur during REM sleep.

Sleep terrors: Sleep terrors are associated with autonomic arousal and screaming. They transpire during the first third of sleep in the slow-wave sleep cycle.

Primary nocturnal enuresis: Bladder instability, which is an uninhibited or reduced threshold for detrusor contraction during bladder filling, and urethral instability, which is a failure of urethral sphincter to adequately relax with bladder filling, are characteristic of youths with primary nocturnal enuresis. Youths with primary nocturnal enuresis may have a relative resistance to an antidiuretic hormone at night. Genetic factors contribute significantly in primary nocturnal enuresis with linkage studies positive on chromosome 8. No correlation exists with sleep stage.

Rhythmic movement disorders: These disorders are related to the developmental age of the child. Head banging and body rocking are the most common presentations of this disorder. Rhythmic movement disorder occurs during sleep onset and stages 1 and 2 sleep (light sleep).

Confusional arousals: In a confusional arousal, the child may awaken from stage 1 and 2 sleep frightened and crying. Only minimal autonomic arousal occurs opposed to the high degree observed in sleep terrors. The patient usually fully awakens before returning to sleep. Confusional arousals are associated with higher rates of delayed sleep onset, night awakening, decreased sleep duration, and bedtime resistance.

Frequency

United States

Surveys report a 20-25% prevalence of youths with some type of sleep problem. The following problems are commonly reported in children aged 2-15 years:

• Nightmares (30%) are more common in younger youths.
• Sleepwalking with at least more than 1 episode occurs in 25-30% of youths and is most common in children aged 3-10 years.
• Insomnia occurs in 23% of youths.
• Enuresis occurs from 8% in children aged 4 years to 4% in children aged 10 years.
• Bruxism is reported in 10% of youths and may occur in people of any age.
• Grinding and clenching teeth at night is reported in 5-8% of adults.
• Sleep rocking or head banging is reported in 5% of youths, with head banging being common in infants and in children aged 9 months to 12 years.
• OSAS is the most common reason for sleep laboratory referral and affects an estimated 2% of children.
• Narcolepsy (0.01-0.20%) may be underestimated in children because a classic tetrad of symptoms is uncommon in this age group.
• Bedtime resistance in school-aged children has been reported at 15% and is often associated with limit-setting disorder.
• The results of one population-based study on schoolchildren in Istanbul found that decreased total sleep duration is more prevalent in boys, older children, and children with higher socioeconomic status. Insufficient sleep in these groups may be associated with negative behavioral symptoms and sleep hygiene.^[1]

International

See United States.

Mortality/Morbidity

• Learning difficulties, emotional lability, attentional deficits, disruptive behaviors, social and school impairments, family dysfunction, low self-esteem, depression, anxiety, cognitive dysfunction hyperactivity, irritability, and memory impairment represent common comorbidities and often exert bidirectional or reciprocal influences.
• OSAS may lead to cor pulmonale, pulmonary hypertension, right-sided heart failure, growth retardation, and failure to thrive.