Sleep Physiology in Children

26/4/2014

Sl eep physi ol og y i n chi ldr en

Official rep reprrint from from UpToDate pToDate® www.uptodate.com ©2014 www.uptodate.com ©2014 UpToDate® Slee p physiology physiology in children Authors Merrill S Wise, MD Daniel G Glaze, MD

Section Editor Ronald D Chervin, MD, MS

Deputy Editor Alison G Hoppin, MD

All topics t opics are updated updated as new ev evidence becomes becomes available available and and our peer review process is process is complete. Literature revie w current current through: Mar 2014. | This topic topic la st update d: May 20, 2013. INTRODUCTION — INTRODUCTION — Sleep is an active, dynamic physiologic process that has a critical impact on many aspects of health, daytime function, and developme developm ent. During the first few years of life, a number of important developmental changes occur, leading to the expected adult sleep/wake pattern [ 1-3 1-3]. ]. This topic review will describe normal sleep/wake patterns in infancy and childhood. This will provide background for an evaluative approach to sleep problems in children, which is discussed in a separate topic review. (See "Assessment "Ass essment of sleep disorders disorders in children" children".) .) Sleep stages and architecture in adults are discuss ed in detail separately. separately. (See "Stages and architecture of normal sleep".) sleep" .) SLEEP STATES — STATES — Two distinct sleep states have been identified based on specific physiological variables: rapid eye movement (REM) sleep and nonrapid eye movement (NREM) sleep. Standardized methods have been developed developed with regard to scoring sleep states in adults and infants [ 4,5 4,5]. ]. REM sleep is a physiologically distinct state, characterized by an activated EEG pattern (similar in some respects to t o wakefulness) wakefulness) associated associ ated with marked decrease decrease in muscle t one and episodic episodic bursts bursts of rapid rapid eye movements. Most dreaming occurs during REM sleep [ 6,7 6,7]. ]. NREM sleep is subdivided into three discrete stages based primarily on the EEG. The stages range from N1 (the lightest and often initial stage of sleep) to N3 (deep NREM sleep with a high arousal threshold); N3 corresponds to what was previously scored as stages stag es 3 and 4. REM sl REM sleep eep was was first characterized in 1953 [8 [ 8]. In 1966, Roffwarg and colleagues sparked interest in the developmen developmental tal aspects of sleep when when they reported reported that newborns spend newborns spend significantly significantly more time in REM sleep as compared with older individuals [1 [ 1]. These investigators postulated that activation of key portions of the central and autonomic nervous system during REM sleep contributed to functional maturation. This hypothesis helped explain a number number of differences in the sleep of infants compared with adults, as described below. Availability of all-night polysomnography in children has allowed more precise characterization of sleep architecture and has improved our understanding of the pathophysiology of many sleep disorders in children. MATURATION OF SLEEP ARCHITECTURE — ARCHITECTURE — Sleep-wake patterns become more diurnal, and sleep times gradually decrease from infancy through adolescence, as shown in the figure ( figure 1). 1). Sleep time of children in a given age group varies by as much as two hours. In addition, sleep patterns and behaviors have changed over time, such that sleep duration in equivalent age groups has declined, presumably reflecting socio-cultural changes [ 9]. Sleep times for children in the United States tend to be shorter than those in Europe and Australian series, especially on weekdays [10,11 [ 10,11]. ]. In a survey of adolescents in the United States, more than 60 percent reported sleeping less than seven hours on weekday nights, substantially less than the 8.5 to 9.5 hours recommended by the CDC [12 [ 12]. ]. http://w http://ww ww.upt w.uptoda odate.co te.com/ m/cont content ents/sleep-ph s/sleep-phy ysiology siolog y-in-children?to -i n-children?topicKey picKey=PEDS%2F6354& =PEDS%2F6354&elapse elapsedTimeMs=3&so dTimeMs=3&source=search_resu urce=search_result&searchTerm lt&searchTerm=sue%C3%… =sue%C3%…

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Sleep physiology in children

Infants — Sleep in the healthy full-term newborn is distinguished from that of older individuals by [ 1,3]: Longer sleep duration (16 to 18 hours per 24 hours) REM sleep occurring at sleep onset Increased proportion of REM sleep REM-NREM cycle much shorter in duration as compared with older individuals With maturation of the child's central nervous system, predictable changes occur, including gradual decrease in total sleep time and the proportion of REM sleep, progressive lengthening of the REM-NREM cycle, and shift to the adult pattern of sleep onset via NREM sleep. Children and adolescents — In normal older children and adolescents, sleep is characterized by: Onset via NREM sleep NREM sleep occupying approximately 75 percent of total sleep time REM and NREM sleep alternating throughout the night with a period of 90 to 100 minutes, and a progressive lengthening of the duration of REM sleep periods in the final one-third of the night. Sleep in adolescents is further characterized by [10,13]: Decrease in slow wave sleep beginning in puberty and continuing into adulthood Physiological shift in sleep onset to a later time Increasing irregularity of sleep-wake patterns (primarily discrepancy between weeknights and weekend sleep patterns). Decrease in average sleep duration despite relatively stable sleep requirement of about nine hours A more detailed discussion of sleep stages and sleep architecture in adults is presented elsewhere. (See "Stages and architecture of normal sleep".) ASSOCIATION OF SLEEP DISORDERS WITH SLEEP STATES — The distinctive physiology of NREM sleep, REM sleep, or transitions between sleep and wakefulness can influence the timing and nature of specific sleep disorders. NREM sleep — NREM parasomnias are characterized by impaired arousal from deep NREM sleep. Certain features of wakefulness and sleep occur simultaneously. These parasomnias tend to arise during the first one-third of the night when deep NREM sleep is common [14,15]. Disorders of arousal from NREM sleep include sleep walking, sleep terrors, and confusional arousals. (See "Sleepwalking and other parasomnias in children", section on 'Disorders of arousal from non-rapid eye movement (NREM) sleep'.) REM sleep — REM sleep phenomena tend to occur in the latter portion of the sleep period when REM sleep predominates [16,17]. These include nightmares, REM sleep behavior disorder, and sleep paralysis. (See "Sleepwalking and other parasomnias in c hildren", s ection on 'Parasomnias usually associated with rapid eye movement (REM) sleep'.) Other respiratory problems (eg, obstructive sleep apnea) also tend to be more severe during REM sleep, although they may occur at any time during the night. This is because upper airway obstruction is often more severe during REM (when muscle tone is markedly reduced compared with wakefulness) and light NREM sleep [ 18,19]. (See "Mechanisms and predisposing factors for sleep related breathing disorders in children", section on 'Changes in respiratory physiology during sleep'.) Slee p-wake transition disorders — Sleep-wake transition disorders occur during the transition from wakefulness to sleep, from sleep to wakefulness, or less commonly, during sleep stage transitions [ 18]. These disorders include rhythmic movement disorder, sleep starts, sleep talking, and nocturnal seizures. (See "Sleepwalking and other parasomnias in children".) No association — Other parasomnias (eg, sleep bruxism and nocturnal enuresis) may occur during any sleep http://www.uptodate.com/contents/sleep-physiology-in-children?topicKey=PEDS%2F6354&elapsedTimeMs=3&source=search_result&searchTerm=sue%C3%…

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stage and at any time of the night [ 18]. SUMMARY REM sleep is associated with marked decrease in muscle tone and episodic bursts of rapid eye movements. Most dreaming occurs during REM sleep. (See 'Sleep states' above.) NREM sleep is subdivided into three discrete stages based primarily on the EEG. The stages range from N1 (lightest sleep) to N3 (deepest NREM sleep with a high arousal threshold). (See 'Sleep states' above.) As compared with older children and adults, newborn infants have longer sleep duration and an increased proportion of REM sleep, and shorter REM-NREM cycles. Sleep-wake patterns become more diurnal, and sleep times gradually decrease from infancy through adolescence ( figure 1). (See 'Maturation of sleep architecture' above.) NREM parasomnias are characterized by impaired arousal from deep NREM sleep, and tend to occur in the first one-third of the night. They include sleep walking, sleep terrors, and confusional arousals. (See 'NREM sleep' above.) REM sleep phenomena tend to occur in the latter portion of the night, including nightmares, REM sleep behavior disorder, and sleep paralysis. Sleep apnea also tends to be more severe during REM sleep. (See 'REM sleep' above.) Sleep-wake transition disorders include rhythmic movement disorder, sleep starts, sleep talking, and nocturnal s eizures. (See 'Sleep-wake transition disorders' above.)

Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Roffwarg HP, Muzio JN, Dement WC. Ontogenetic development of the human sleep-dream cycle. Science 1966; 152:604. 2. ASERINSKY E, KLEITMAN N. A motility cycle in sleeping infants as manifested by ocular and gross bodily activity. J Appl Physiol 1955; 8:11. 3. Anders TF, Sadeh A, Appareddy V. Normal sleep in neonates and children. In: Principles and Practice of Sleep Medicine in the Child, Ferber R, Kryger M (Eds), W.B. Saunders, Philadelphia 1995. p.7. 4. Iber C, Ancoli-Israel S, Chesson AL, et al. The AASM Manual for the Scoring of Sleep and Associated Events, American Academy of Sleep Medicine, West Chester, IL 2007. 5. A manual of standardized terminology, tec hniques and criteria for scoring of states of sleep and wakefulness in newborn infants, Anders T, Emde R, Parmelee AH (Eds), UCLA Brain Information Service, NINDS Neurological Information Network, Los Angeles 1971. 6. DEMENT W, KLEITMAN N. Cyclic variations in EEG during sleep and their relation to eye movements, body motility, and dreaming. Electroencephalogr Clin Neurophysiol 1957; 9:673. 7. DEMENT W, KLEITMAN N. The relation of eye movements during sleep to dream activity: an objective method for the study of dreaming. J Exp Psychol 1957; 53:339. 8. ASERINSKY E, KLEITMAN N. Regularly occurring periods of eye motility, and concomitant phenomena, during sleep. Science 1953; 118:273. 9. Iglowstein I, Jenni OG, Molinari L, Largo RH. Sleep duration from infancy to adolescence: reference values and generational trends. Pediatrics 2003; 111:302. 10. Olds T, Maher C, Blunden S, Matricciani L. Normative data on the sleep habits of Australian children and adolescents. Sleep 2010; 33:1381. http://www.uptodate.com/contents/sleep-physiology-in-children?topicKey=PEDS%2F6354&elapsedTimeMs=3&source=search_result&searchTerm=sue%C3%…

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11. Blair PS, Humphreys JS, Gringras P, et al. Childhood sleep duration and associated demographic characteristics in an English cohort. Sleep 2012; 35:353. 12. Eaton DK, McKnight-Eily LR, Lowry R, et al. Prevalence of insufficient, borderline, and optimal hours of sleep among high school students - United States, 2007. J Adolesc Health 2010; 46:399. 13. Sadeh A, Dahl RE, Shahar G, Rosenblat-Stein S. Sleep and the transition to adolescence: a longitudinal study. Sleep 2009; 32:1602. 14. Gastaut H, Broughton RJ. A clinical and polygraphic study of episodic phenomena during sleep. Biol Psyc hiatry 1965; 7:197. 15. Keefauver SP, Guilleminault C. Sleep terrors and sleep walking. In: Principles and Practice of Sleep Medicine, 2nd ed, Kryger MH, Roth T, Dement WC (Eds), WB Saunders, Philadelphia 1994. p.567. 16. Fisher C, Byrne J, Edwards A, Kahn E. A psychophysiological study of nightmares. J Am Psychoanal Assoc 1970; 18:747. 17. Schenck CH, Bundlie SR, Ettinger MG, Mahowald MW. Chronic behavioral disorders of human REM sleep: a new category of parasomnia. Sleep 1986; 9:293. 18. American Academy of Sleep Medicine. International class ification of sleep disorders, 2nd ed: Diagnostic and coding manual, American Academy of Sleep Medicine, W estchester, IL 2005. 19. Huang J, Karamessinis LR, Pepe ME, et al. Upper airway collapsibility during REM sleep in children with the obstructive sleep apnea syndrome. Sleep 2009; 32:1173. Topic 6354 Version 7.0

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GRAPHICS

Average sleep time for children

Mean sleep time of 493 healthy Swiss children enrolled in the Zurich Longitudinal Studies, based on parent report. Error bars represent ±2 standard deviations (which includes 97 percent of the population). The dashed red line represents the lower limit of sleep time for each age group, as recommended by the Centers for Disease Control and Prevention (CDC). Data from: Iglowstein I, Jenni OG, Molinari L, Largo RH. Sleep duration from infancy to adolescence: Reference values and generational trends. Pediatrics 200 3; 111:302. Graphic 82604 Version 2.0


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Disclosures Me rrill S Wise , MD Nothing to disc lose. Daniel G Glaze, MD Grant/Research Support: Neuren Pharmaceuticals (Rett syndrome). Ronald D Chervin, MD, MS Grant/Research/Clinical Trial Support: Philips Respironics; Fisher Paykel (sleep apnea). Consultant/Advis ory Boards: Proctor & Gamble; MC3; Zans ors (sleep). Patent and Copyright Holder: University of Michigan (diagnosis and treatment of sleep disorders ). Employment: Univers ity of Michigan Health Sys tem, Sleep Disorders Center (s leep disorders) . Other Financial Interest: Regents of University of Michigan (Pediatric Sleep Questionnaire); A merican A cademy of Sleep Medicine (s leep); International Pediatric Sleep A ss ociation (s leep). Alison G Hoppin, MD Employee of UpToDate, Inc. Contributor disc losures are rev iew ed for c onflicts of interest by the editorial group. When found, these are address ed by vetting through a multi-level review proces s, and through requirements f or ref erences to be provided to support the content. Appropriately ref erenced content is required of all authors and must conform to UpToDate standards of evidence. Conflict of interest policy Di scl osures:


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Sleep Physiology in Children

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