The clinical spectrum of sleep disorders in children is broad, ranging from primary snoring and obstructive sleep apnea (OSA) syndrome to complex sleep-related behaviors and movement disorders. Although snoring and OSA typically receive significant attention and discussion, other biologically based sleep disorders are as common, if not more common, in children. A general pediatrician is frequently presented with the complaint of sleep talking, sleep walking, or abnormal movements during sleep. Even more alarming is the presentation of the child suddenly and explosively screaming during sleep. Such complaints fall under the category of parasomnias. Parasomnia refers to a group of conditions associated with complex motor behaviors and experiential phenomena arising from various stages of sleep and occasionally resulting in unintentional violence and/or injury. Exclusive to sleep and wake-to-sleep transitions, these phenomena include arousals with abnormal motor, behavioral, autonomic, or sensory symptoms. Parasomnias can be noticeably dissimilar in clinical manifestations, but most share biologic characteristics.
Three parasomnias associated with loud vocalizations associated with sleep that can present to general practitioners include sleep terrors, nightmares, and rapid eye movement sleep behavior disorder (RBD). Although usually benign, these sleep disorders can be disruptive and even potentially dangerous to the patient and can often be threatening to quality of life.1 In this article, we describe the clinical features of some of these disorders and how to differentiate between their alarming presentations.
Evaluation of The History and Physical Examination
The evaluation of parasomnia symptoms begins with a comprehensive medical history and physical examination. These are essential and are usually sufficient to make an accurate diagnosis without the need for further testing. A detailed description of abnormal sleep behaviors is critical to identifying the diagnosis. Important questions in the evaluation of parasomnias are listed in Sidebar 1.
Key Questions in the Evaluation of a Parasomnia
- What specifically happens during the event and what symptoms are present?
- Does the child interact with you during the event?
- Does the child remember the episode?
- Does the child recall having a dream? If so, what are the details of the dream?
- What is the intensity of autonomic discharge? (Is the child’s heart “racing”?)
- Is agitation present or absent during the episode?
- What is the response to intervention? Are symptoms better or worse?
- When does the event take place during the sleep period?
- What is the duration of the episode or spell?
- What, if any, symptoms are present after waking?
- Is there a history of stereotypic activity during sleep?
Key Questions in the Evaluation of a Parasomnia
A careful assessment of the patient’s sleep history should take place during the evaluation. The presence of behavioral or developmental abnormalities while awake may suggest other underlying sleep disorders, such as OSA, circadian rhythm disturbances, arousal disorders, or medication effects. Sleep/wake schedules, habits, and the typical pattern of the appearance of these sleep behaviors requires delineation. Morning wake time, evening bedtime, and nap time rituals require description. Sleep logs or diaries and video recordings of the episodes often reveal identifiable characteristics and can be very helpful in understanding the nature of the occurrences. Evaluating for the presence of excessive daytime sleepiness, unintentional sleep episodes/sleep attacks, restless sleep, limb movements during sleep, and/or snoring may assist in determining precipitating factors.2 The use of a tool guiding history taking, such as the BEARS questionnaire, can be helpful in this aspect of the evaluation.3 A careful review of the child’s family history is also important because many parasomnias exhibit a familial pattern.
A complete physical examination with emphasis placed on neurologic function and developmental assessment is required because developmental delays, a history of chronic illness, or symptoms suggestive of neurologic disorders might indicate an organic cause for symptoms. Comorbid states can be present. The identification and treatment of primary sleep disorders, such as the continuum of pediatric OSA or periodic limb movement disorder (PLMD), must be addressed first. The treatment of pediatric OSA and PLMD may result in the resolution of parasomnia symptoms. In some instances, a urine drug screen might be helpful if there is concern that the symptoms may be a side effect of or an adverse reaction to a medication or illicit substance, particularly in older children and adolescents.
Home video recording of the spells often provides important diagnostic information. Under certain circumstances, video polysomnography is indicated.4,5 Using an expanded electroencephalographic (EEG) electrode array during polysomnography provides additional information and increases sensitivity for identifying neurologic pathology, such as frontal lobe seizures. Concurrent video recording of the patient during polysomnography is important to document symptoms and movements and to document the absence of seizure activity during this motor activity.6
If polysomnography is conducted, it can be helpful to have the patient drink fluids and avoid urination before lights out because bladder distention may precipitate some partial arousals from sleep.2 In addition to identifying primary sleep-related pathology that may be a factor in the precipitation of spells or fragmentation of sleep (eg, pediatric OSA and PLMD), analysis of the polysomnogram should place special emphasis on the identification of an increased amplitude of slow waves, intermittent synchronization of slow wave activity just before a spell, arousal rhythms occurring during slow wave sleep, and intrusion of 4- to 7-Hz EEG activity.2 These findings are suggestive of partial arousals from non–rapid eye movement (NREM) sleep such as sleep terrors.
Other common polysomnographic findings include movement arousals without a change in sleep state, frequent arousal rhythms on electroencephalography without state change, and theta-delta sleep pattern. These findings are associated with, but not diagnostic of, disorders of arousal from NREM sleep.2 However, the lack of an event during a polysomnogram does not preclude the diagnosis of a parasomnia; a thorough history and detailed description of the event are extremely important in the diagnosis.
The term “sleep terror” is preferred to “night terror” because sleep terrors can occur during any sleep period, including daytime naps. It also allows for the clear differentiation between the term for this disorder and nightmares. The onset of a sleep terror is sudden, abrupt, striking, and frightening to the observer. Sleep terrors are associated with profound autonomic discharges and behavioral manifestations of intense fear.2,7,8 Caregivers are frequently alarmed and distressed at the startling appearance of the child.
Similar to other NREM parasomnias, the exact prevalence of sleep terrors is unknown. Males are typically affected more frequently than females, and a clear familial pattern is common. The onset of symptoms typically occurs between 2 and 4 years of age with a resolution of symptoms by adolescence. Precipitating factors are similar to other NREM parasomnias and include fever, bladder distention, sleep deprivation, stress, and use of central nervous system depressant medications. Symptoms tend to decrease during puberty and rarely persist into adolescence. Clinically, significant psychopathology can be associated with sleep terrors in adolescents and adults, but it is unusual in children.
Sleep terrors typically occur in the first half of the night and in most cases will consistently occur a specific amount of time after sleep onset. They usually begin with the child suddenly sitting upright in bed and emitting a powerful, piercing scream. Severe autonomic discharge occurs and manifests as wide open eyes with dilated pupils, tachycardia, tachypnea, diaphoresis, and increased muscle tone. During the sleep terror, the child is often unresponsive. Nonetheless, the child may respond in an unusual manner or might follow simple commands. Efforts to restrain or console the youngster might exacerbate autonomic and motor activity. If awakened, the child is confused and disoriented and amnestic of the event. In contrast to confusional arousals, another form of parasomnia, episodes of sleep terrors are usually brief, lasting only a few minutes and subsiding spontaneously. If the child awakens, he/she is typically able to return to sleep shortly after the event.
Diagnosis is based on the identification of these symptoms and the exclusion of organic pathology. Polysomnography is indicated in cases in which symptoms are causing the family significant concern or if there is a reason to suspect an organic sleep disorder. Sudden arousals from slow wave sleep during the first one-third to first one-half of the major nocturnal sleep period may be observed if a study is completed. Although sleep terrors are most common during the first one-third to one-half of the sleep period, they can occur at any time during the night. Partial arousals without motor manifestation occur more frequently in children with sleep terrors compared with normal children. Autonomic discharge, as represented by tachycardia, can be noted during these partial arousals without full-blown symptoms of a night terror.
Given the degree of autonomic discharge, sleep terrors must be distinguished from partial complex seizures. Sleep terrors are clinically differentiated from partial complex seizures by their characteristic history and clinical course. Epileptic events may also be distinguished from disorders of partial arousal by the presence of a combination of clinical features and stereotypic behaviors and that they may also occur during wakefulness. However, the identification of epileptiform activity during polysomnography does not completely rule out the presence of a partial arousal because they may occur concomitantly in the same patient. Patients should also be evaluated for causes of sleep fragmentation such as pediatric OSA or PLMD because the arousals associated with these disorders can trigger episodes.
Severe cases may warrant medical therapy. Severity is usually based on the degree of impairment of the child’s daytime functioning or if the sleep of family members is being significantly affected. Benzodiazepines or low doses of gabapentin have been successful in treating sleep terrors. However, in most cases, assurance of proper sleep hygiene, decreasing stressful situations, treating fevers, protection from injury and reassurance are all that are necessary when managing sleep terrors.
In summary, sleep terrors occur in a small percentage of young children and manifest as alarming episodes of autonomic discharge, usually during the first half of the night, to which the child is amnestic. In general, sleep terrors are limited to childhood and resolve before adolescence. Treatment is based on severity, but often reassurance is adequate. An evaluation for the causes of partial arousals including bladder distention and sleep fragmentation from organic sleep disorders such as sleep-disordered breathing, PLMD, or a seizure disorder should be performed.
A nightmare occurs during rapid eye movement (REM) sleep and is manifested by a frightening dream followed by a prolonged period of wakefulness.2,9–11 Clear recall of the dream with varying degrees of anxiety may be present. Nightmares are characterized by a sudden arousal from REM sleep to a fully awake state. In contrast to night terrors, the youngster is fully oriented to the environment, and sensorium is clear during these events. Mild autonomic nervous system discharges may occur and typically reflect the degree of anxiety associated with the dream.
Nightmares may occur at anytime during the night but most commonly occur during the last one-half to one-third of the sleep period because this is when REM sleep is more prevalent. The level of dream recall is consistent with the child’s developmental level. A vivid story that requires complex mentation and description is typical. Nightmares are primarily associated with an emotional response rather than the pure autonomic activity exhibited with sleep terrors. Children are usually easily comforted after a nightmare, but return to sleep is delayed. Nearly all youngsters experience a nightmare at one time or another. Because many families do not seek medical attention for nightmares, prevalence data are not clear. The age of onset of nightmares appears to parallel the development of the capacity for dream expression, which can vary with the stage of language development.
Movements, other than the normal twitches and/or other phasic REM activity, are rare during nightmares. Arousal from sleep with vivid dream recall is typical. Clinical symptoms are generally mild, particularly compared with sleep terrors. The diagnosis is based on characteristics such as the time of occurrence, the child’s recollection of a vivid story line, and a prolonged return to sleep. Laboratory investigations are rarely necessary because nightmares and sleep terrors can usually be differentiated on clinical grounds alone.
Polysomnographic findings associated with nightmares typically depict an abrupt waking from REM sleep followed by a somewhat prolonged period of wake after sleep onset. Mild tachycardia may be present depending on the degree of anxiety. Increased eye movement density and increased phasic muscle twitches may be present during REM sleep but are not diagnostic. Focal, paroxysmal, and epileptiform activity are notably absent.
Occasional nightmares during childhood are common, but if they are frequent, persist for prolonged periods, or are associated with daytime behavioral problems, an evaluation for underlying medical or psychological causes should be considered. In most cases, reassurance is sufficient treatment. Behavioral interventions such as establishing a consistent bedtime routine and identifying and addressing stressors can have a significant impact by helping the child relax before bedtime. Further psychological and/or psychiatric evaluations may be needed if nightmares are frequent, severe, or associated with clinical manifestations of other disease processes.
Rapid Eye Movement Sleep Behavior Disorder (RBD)
Unlike night terrors and nightmares, which are typically benign despite their alarming appearance, RBD has the potential for significant injury.12 RBD, also known as REM sleep motor parasomnia, is a condition that results from a lack of the atonia typically associated with REM sleep. RBD is most commonly recognized in adult patients, but approximately 25% of adults with RBD report longstanding prodromes of subclinical RBD that began in adolescence or even childhood.13 With this in mind, pediatricians should be aware of the features of this disorder to allow for early diagnosis and to prevent unnecessary harm.
RBD is defined as abnormal behaviors occurring during REM sleep that may cause injury to self or others or may result in sleep disruption.14 According to the 2nd edition of the International Classification of Sleep Disorders, a diagnosis of RBD requires the following: the presence of either sleep-related injurious behaviors (dream enactment behavior) by history or abnormal REM sleep behavior during polysomnography; the absence of EEG epileptiform activity during REM sleep; and the sleep disorder is not better explained by another sleep, medical, mental or neurologic disorder or medication-related effect or substance-abuse disorder.
RBD should be suspected in a child with any of the following symptoms: dream enactment, complaint of vivid dreams that are often scary or frightening, new onset of restless sleep/sleep disruption, thrashing in bed, falling out of bed, sleep-related injury, or new onset of sleep talking or shouting. In a child with a history of sleep talking, a diagnosis of RBD should be considered if intensification of the symptom, specifically an increase in volume or duration of the sleep talking behavior, is noted.
An essential feature of RBD is dream enactment behavior.13 This appears to be caused by the absence of normal REM sleep skeletal muscle atonia. Paradoxic muscle activity in REM sleep results in gross complex body movements allowing for “acting-out” dreams. Adults can typically report vivid dream recall after a spell. Dream recall may be more difficult to elicit and content may not be as clear in a child, but it can be present.
Symptoms of RBD in children and adolescents are based on a clinical history of movement and apparent dream enactment. Nonetheless, this may often be difficult to clinically differentiate from confusional arousals in which there may be a report of a dream of being chased or attacked, agitation, and unusual and/or aggressive movements during a spell. The time of night and a history of NREM parasomnia may be helpful in differentiation. Symptoms of RBD in adults include talking, laughing, shouting, gesturing, reaching, grabbing, arm flailing, punching, kicking, sitting up, leaping from bed, crawling, and running. Quiet walking is uncommon. These symptoms can be similar to symptoms classically associated with NREM partial arousal disorders including but not limited to sleep terrors, agitated sleepwalking, and confusional arousals. RBD differs from sleep terrors and NREM parasomnias by considerable motor activity and state dissociation during REM sleep, such that the patient does not interact with the surroundings during the episode. In sleepwalking, an NREM parasomnia, patients can open a door, navigate through the house, and even cook because they are able to interact with the environment. However, in RBD, the patient interacts with the dream environment rather than the physical environment. This can lead to significant injury for patients if, for example, they are dreaming of running through a field but are actually running in their bedroom. This inability to interact with the physical environment during episodes is characteristic of RBD.
If completed, polysomnography reveals increased muscle tone and frequent limb movements that persist even in REM sleep or complex behaviors performed during REM sleep. Increased phasic muscle activity and excessive limb movements are also noted during polysomnography. No epileptiform activity is noted on the electroencephalogram.
Interestingly, one of the more commonly appreciated associations with RBD is narcolepsy. Nevsimalova et al15 reported RBD as the presenting symptom of narcolepsy with cataplexy in two children. Along with the onset of excessive daytime sleepiness and cataplexy, the patients exhibited restless sleep, nightmares, and movements during sleep, somniloquy, and harmful behaviors during sleep. RBD has been reported in about one third of adults with narcolepsy with cataplexy.16 If RBD is suspected in a child, evaluation for narcolepsy is recommended.
In addition to narcolepsy, RBD is described in association with a number of other pediatric conditions (see Sidebar 2). Lloyd et al17 retrospectively evaluated 15 patients with symptoms of RBD and REM sleep without atonia. The mean age at diagnosis was 9.5 years with a range of 3 to 17 years. Nightmares were reported in 13 of the patients. Excessive daytime sleepiness was noted in about half of these patients. Other comorbid states included anxiety, posttraumatic stress disorder, attention-deficit disorder, developmental delay, Smith-Magenis syndrome, pervasive developmental disorder, narcolepsy, idiopathic hypersomnia, and Moebius syndrome. Reviewing both the presentation of RBD and how patients respond to therapy, specifically benzodiazepines and melatonin, RBD may be associated with neurologic abnormalities, narcolepsy, or medication. However, an association with specific neurodegenerative disorders is not common.18
Medical Conditions Associated with REM Behavioral Disorder15–18
- Brainstem trauma
- Antidepressant medications
- Parasomnia overlap disorder
- Olivopontocerebellar degeneration
- Multiple sclerosis
- Group A xeroderma pigmentosum
- West syndrome (infantile spasms)
- Congenital Moebius syndrome
- Parasomnia overlap disorder
- Neurofibromatosis type I
- Tourette syndrome
- Smith Magenis syndrome
REM = rapid eye movement.
RBD represents persistent state dissociation during REM sleep associated with paradoxic motor activity and vivid dream recall that can result in injury in children and adolescents.19 This motor dyscontrol may be a final common pathway for a variety of disorders ranging from narcolepsy with cataplexy, post-traumatic stress disorder,20 and autism spectrum disorder.21 Interestingly, motor activity during REM sleep in early infancy is common and normal, resulting in the term “active sleep.” This suggests that RBD may also occur in otherwise normal children and represent dysfunction of maturation, particularly in the pontine tegmental region.22,23 By clinical history alone, other more commonly recognized childhood parasomnias such as confusional arousals, sleepwalking, and sleep terrors might be considered. However, these NREM partial arousal disorders are characteristically associated with amnesia for the event and absence of vivid dream recall and occur during the first one-third to one-half of the sleep period. Nonetheless, diagnosis can be difficult and requires a high index of suspicion.
When symptoms suggestive of RBD occur in children or adolescents, underlying etiologies and/or comorbidities require comprehensive evaluation, which may include polysomnography and multiple sleep latency testing. After exclusion and treatment of other comorbidities, RBD is typically treated with benzodiazepines. Melatonin has also been shown to be effective. Unlike sleep terrors and nightmares, evaluation by a pediatric sleep medicine specialist is recommended if the diagnosis of RBD is considered. Further research and longitudinal studies aimed at learning about the epidemiology, pathophysiology, and predictive significance of REM sleep motor dyscontrol during childhood are required.
General pediatricians are commonly faced with challenging questions regarding behaviors, such as talking or limb movement, during sleep. These behaviors may be part of normal neurodevelopment or they may represent a more concerning sleep-related behavioral disorder. Sleep terrors, nightmares, and RBD share many common features but have drastically different clinical implications ranging from self-limited amnestic to potentially life-threatening events. Identifying characteristic features of each (see Table) may allow practitioners to provide families with reassurance or identify patients who require further evaluation by a pediatric sleep medicine specialist.
Characteristic Features of Sleep Terrors, Nightmares, and RBD
- Avidan AY, Kaplish N. The parasomnias: epidemiology, clinical features, and diagnostic approach. Clin Chest Med. 2010;31(2):353–370. doi:10.1016/j.ccm.2010.02.015 [CrossRef]
- Sheldon SH. The parasomnias. In: Sheldon SH, Ferber R, Kryger MH, eds. Principles and Practice of Pediatric Sleep Medicine. Philadelphia: Elsevier and Saunders; 2005:305–315. doi:10.1016/B978-0-7216-9458-0.50031-3 [CrossRef]
- Owens JA, Dalzell V. Use of the ‘BEARS’ sleep screening tool in a pediatric residents’ continuity clinic: a pilot study. Sleep Med. 2005;6(1):63–69. doi:10.1016/j.sleep.2004.07.015 [CrossRef]
- deLissovoy V. Head banging in early childhood: A study of incidence. J Pediatr. 1961;58:803–805. doi:10.1016/S0022-3476(61)80135-2 [CrossRef]
- Golbin AZ. Movements as an active factor in organization of sleep. Hum Physiol. 1976;3:354.
- Kravitz H, Rosenthal V, Teplitz Z, Murphy JB, Lesser RE. A study of head-banging in infants and children. Dis Nerv Syst. 1960;21:203.
- Broughton R. Childhood sleep walking, sleep terrors and enuresis nocturna: their pathophysiology and differentiation from nocturnal epileptic seizures. Sleep.1978;103–111.
- Kales A, Soldatos CR, Bixler EO, et al. Hereditary factors in sleepwalking and night terrors. Br J Psychiatry. 1980;137:111–118. doi:10.1192/bjp.137.2.111 [CrossRef]
- Guilleminault C. Narcolepsy and its differential diagnosis. In: Guilleminault C, ed. Sleep and Its Disorders in Children. New York: Raven Press;1987:181–194.
- Mack JE. Nightmares and the Human Conflict. Boston: Little, Brown Co;1970.
- Foulkes D. Children’s Dreams: Longitudinal Studies. New York: Wiley;1982.
- Schenck CH, Lee SA, Bornemann MA, Mahowald MW. Potentially lethal behaviors associated with rapid eye movement sleep behavior disorder: review of the literature and forensic implications. J Forensic Sci. 2009; 54(6):1475–1485. doi:10.1111/j.1556-4029.2009.01163.x [CrossRef]
- Schenck CH, Bundlie SR, Ettinger MG, Mahowald MW. Chronic behavioral disorders of human REM sleep: a new category of parasomnia. Sleep. 1986;9:293–308.
- American Academy of Sleep Medicine. International Classification of Sleep Disorders: Diagnostic and Coding Manual. 2nd ed. Westchester, IL: American Academy of Sleep Medicine;2005.
- Nevsimalova S, Prihodova I, Kemlink D, Lin L, Mignot E. REM behavior disorder (RBD) can be one of the first symptoms of childhood narcolepsy. Sleep Med. 2007;8(7–8):784–786. doi:10.1016/j.sleep.2006.11.018 [CrossRef]
- Nightingale S, Orgill JC, Ebrahim IO, de Lacy SF, Agrawal S, Williams AJ. The association between narcolepsy and REM behavior disorder (RBD). Sleep Med. 2005;6(3):253–258. doi:10.1016/j.sleep.2004.11.007 [CrossRef]
- Lloyd R, Tippmann-Peikert M, Slocumb N, Kotagal S. Characteristics of REM sleep behavior disorder in childhood. J Clin Sleep Med. 2012;8(2):127–131.
- Boeve BF, Silber MH, Saper CB, et al. Pathophysiology of REM sleep behavior disorder and relevance to neurodegenerative disease. Brain. 2007;130(Pt 11):2770–2788. doi:10.1093/brain/awm056 [CrossRef]
- Stores G. Rapid eye movement sleep behaviour disorder in children and adolescents. Dev Med Child Neurol. 2008;50(10):728–732. doi:10.1111/j.1469-8749.2008.03071.x [CrossRef]
- Sheldon SH, Jacobsen J. REM-sleep motor disorder in children. J Child Neurol. 1998;13(6):257–260. doi:10.1177/088307389801300603 [CrossRef]
- Thirumalai SS, Shubin RA, Robinson R. Rapid eye movement sleep behavior disorder in children with autism. J Child Neurol. 2002;17(3):173–178. doi:10.1177/088307380201700304 [CrossRef]
- Chadwick D, Hallet M, Harris R, Jenner P, Reynolds EH, Marsden CD. Clinical, biochemical, and physiological features distinguishing myoclonus responsive to 5-hydroxytryptophan, tryptophan with monoamine oxidase inhibitor and clonazepam. Brain. 1977;100(3):455–487. doi:10.1093/brain/100.3.455 [CrossRef]
- Green RA, Gillin JC, Wyatt RJ. The inhibitory effect of intraventricular administration of serotonin on spontaneous motor activity of rats. Pyschopharmacology. 1976;51(1):81–84. doi:10.1007/BF00426326 [CrossRef]
Characteristic Features of Sleep Terrors, Nightmares, and RBD
|Typical Age of Presentation
||Adolescence into adulthood
|Associated Sleep Stage
|Typical Time of Night
||Occur anytime during period of sleep
||Occur in last half to third of sleep period
||Occurs in last half to third of sleep
- Abrupt awakening, typically associated with a scream
- Intense autonomic discharge including tachypnea, tachycardia, and sweating
- Typically cannot be soothed or comforted during the episode
- Child is amnestic at the time of event and the following morning
- Brief, lasting a few minutes
- Awake in state of distress after distressing dream with negative emotional response
- Mild tachycardia associated with level of anxiety response
- Dream is typically recalled in detail after the event and the following morning
- Associated with prolonged period of wakefulness after the event
- Occurs in last half to third of sleep
- Talking, shouting, gesturing during sleep
- Dream enactment behavior with potentially injurious behavior
- Vivid dream recall after the event
- May be presenting sign of narcolepsy
- Can be associated with other neurologic disease