1087-0792/$ -doi:10.1016/j.

Sleep Medicine Reviews (2009) 13, 107e110

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GUEST EDITORIAL

Pediatric sleep disorders: How can sleep-medicinemake a difference?

Sleep problems in children are brought up regu-larly by parents to pediatricians. Many children arenow referred for evaluation of sleep-relateddisorders, particularly obstructive sleep apnea. Ashealth care providers, our focus should be on doinga better job of defining obstructive sleep apneasyndrome and recognizing sleep-related disordersin this pediatric group.

Spicuzza and colleagues emphasized theimportance of distinguishing between two groups;obese children with sleep-disordered breathing(SDB) and normal weight children with SDB. Bothgroups present differently and have differingclinical syndromes. This is an important differen-tiation, especially when considering metabolic andimmunological changes that are present in obesechildren with SDB, as obesity induces healthchanges that are independent from an isolatedupper airway problem. In children with predomi-nant central obesity, many factors are in play andthe upper airway problem is likely a consequenceof obesity itself. Obese children may suffer fromchest bellows inducing symptoms of SDB, particu-larly seen during rapid eye movement (REM) sleepwith muscle atonia. Pulmonary function testing onobese children during wakefulness in supine posi-tion may be helpful to see if abdominal obesity isa contributing factor to abnormal breathing duringsleep. Obese children have abnormal adipocyteactivity, and the dysregulation of these cellsleads to abnormal metabolic and immunologicalresponses. Such abnormal responses are not asso-ciated with upper airway problems during sleep innormal weight children. Considering the obesityepidemic, it is important to understand the role ofadipocytes, their circadian regulation and inter-action between sleep and the secretions of variouspeptides from these cells. The distinction between

see front matter ª 2008 Elsevier Ltd. All rights resersmrv.2008.11.002

the obese child with SDB and co-morbidities froma normal weight child with SDB is therefore,a crucial one.

Appropriate treatment options for sleep-relateddisorders in children are areas in need of furtherresearch. A normal weight child with SDB may bemore amenable to the type of clinical trials sug-gested by Kuhle et al. However, little can beconcluded from the review performed by theseauthors, as they failed to differentiate betweenthe two groups clearly outlined by Spicuzza et al.to indicate the validity of trials. The authors indi-cated that there is a paucity of data on the validityof adeno-tonsillectomy in children with abnormalbreathing during sleep. The discussion of theorthodontic literature dating back to the 1980swould have been useful, considering the role ofnasal breathing during sleep on maxillo-mandib-ular growth1e3 and the role that adenoids andtonsils play in decreasing upper airway space. Theauthors mentioned that randomized treatmentstudies may be difficult to perform in children. Asuggestion is to question how tonsillectomy isperformed. As common as adeno-tonsillectomymay be in the otolaryngology practice, thisprocedure has been performed in several differentways. In our community we have witnessed threedifferent surgical approaches: partial tonsillec-tomy with retention of the upper third of tonsils,resection of tonsils and fossa wall at the tonsillarinterior limit, and emphasis on elimination of alltonsillar tissue followed by suturing lateral walls ofthe fossa together to avoid pulling of tissue withthe advantage of decreasing risk of bleeding, painand scarring (seen more commonly in secondapproach). Post-surgical scarring can be a long-term consequence of adeno-tonsillectomy and anunwanted consequence especially in an already

ved.

108 Guest editorial

small upper airway. It would be invaluable to havea study comparing the different surgicalapproaches of tonsillectomy and how each maychange treatment outcomes in children with SDB.4

Alves et al. wrote a very useful review on sleepand neuromuscular disorders in children. Treat-ment of sleep-related disorders in this groupdecreases frequency of hospitalizations andimproves quality of life.5 The use of nasal nonin-vasive positive pressure ventilation in infancy andyoung children during wakefulness is still a topicof debate, but the possible contribution to lungdevelopment in congenital syndromes is animportant topic for future research. From recom-mendations made by the authors regarding the useof bilevel pressure, one could add further on thepressure differential between inspiratory (IPAP)and expiratory (EPAP) pressures. The authorsindicate that neuromuscular weakness plays a rolein the loss of coordination between upper airwaydilators and effectiveness of positive inspiratorypressure. In this vulnerable group, a large differ-ential between IPAP and EPAP should be avoideddue to the variability of upper airway musclecontractions in relation to sleep stages and bodyposition. A large differential may actually lead topartial airway obstruction as shown by the pres-ence of flow limitation at the nose. In our practicewe limit the IPAP and EPAP differential to amaximum of 6 cm of H2O in order to avoid iatro-genic induction of some degree of flow limitation.It is important to consider the use of a back-uprespiratory rate, taking into account progression ofthe disease, tolerance by the patient and age. The‘‘rise-time’’ (the speed at which airflow is deliv-ered from expiration to inspiration) is a functionavailable on bilevel machines and a critical factorto consider as it improves patient comfort andcompliance. Finally, evaluation of nasal patencyand initiating appropriate nasal treatment ifnecessary are essential in patient comfort andcompliance with noninvasive positive pressure use.

Simakajornboon et al. wrote an up-to-datereview on RLS/PLMD in children and emphasizedthe negative impact of this condition on health andquality of life. The familial form of the syndromeseems to occur earlier in life than sporadic cases.Our youngest case was recognized at 6 months ofage. Published diagnostic scales are not quiteapplicable to children and this is a handicap. Asmentioned by the authors, dopamine agonists havebeen a successful treatment option in adults,however there is little information on children. Wefollowed 5 of the 6 children who were placed onpramipexol for PLMs for 26e43 months and did notobserve augmentation; they tolerated the drug

and had complete disappearance of PLMs, but hadprogressive increase of dosage overtime.6 Long-term studies on treatment efficacy for RLS/PLMDin children are lacking, and long-term effects ofdopamine agonists should be systematicallyassessed including hormonal impact at time ofpuberty.

Parasomnias are behavioral problems duringsleep that may significantly disturb family life.Kotagal wrote a thorough review on this topic. Hementioned the possibility that parasomnias may berelated to a familial form of frontal lobe seizure(and, rarely, a mesio-temporal focus).7 It isimportant to rule out a seizure disorder as it doesinvolve about 1% of children presenting witha parasomnia. The most interesting developmentin the investigation of parasomnias has been thediscovery that several sleep-related disorders areassociated with NREM sleep parasomnias,8e10 andthat treatment of the underlying sleep disordermay eliminate the parasomnias.9 When performingquantified electroencephalographic (EEG) analysesof each sleep cycle during the night, EEG record-ings during sleep have shown that chronic sleep-walking and sleep-terrors were associated with anabnormal distribution of the delta power duringtotal nocturnal sleep.11,12 These changes werecorrelated with the cyclic alternating pattern(CAP) analyses, demonstrating the usefulness ofthis sleep scoring system.13 There is an abnormalintrusion of CAP phase B interrupting the conti-nuity of slow delta activity.14 Whether theabnormal CAP is an indication of the presence ofanother sleep-related disorder, or is a necessaryelement for recurrence of the parasomnia isa question that requires further investigation. It isworth pointing out that sleep enuresis (considereda parasomnia), has been eliminated when a childundergoes orthodontic treatment for SDB withrapid maxillary expansion (RME).15,16 RME expandsthe naso-maxillary complex and has been shown tobe a successful treatment option for SDB inchildren.17

Recently, two different groups have questionedif bruxism is actually a ‘‘protective’’ mechanismdeveloped in those with SDB in an effort to openthe upper airway.18,19 Epidemiological studieshave shown that SDB is the most common asso-ciation with bruxism.20 Clearly, the investigationof the interaction between parasomnias and othernocturnal sleep disturbances needs to bepursued.

Nevsimalova emphasized that there is an under-diagnosis of narcolepsy in the pediatric pop-ulation. We would add that narcolepsy is oftenmisdiagnosed. In our practice we see many

Pediatric sleep disorders 109

teenagers who have already been placed on stim-ulants such as modafinil or amphetamine-basedcompounds, and most of the time the decision isbased on limited information. As mentioned, sleepparalysis and hypnagogic hallucinations are alsoseen in the normal population and with anysyndrome that causes daytime sleepiness. Thediagnosis of cataplexy may be difficult if the eventis not witnessed by a specialist familiar with thesymptoms. Clinicians should be cautious whenlabeling a cataplectic event in the setting of‘‘partial muscle weakness’’ lasting for more than5 min and not triggered by obvious stimuli partic-ularly laughter.

Even though the HLA DQB1*0602 is a usefulmarker, it is important to keep in mind thata significant number of the population are positivefor this haplotype without any evidence of narco-lepsy. We frequently receive consultations onteenagers presenting with a history of great diffi-culty getting out of bed in the morning, havingexcessive daytime sleepiness, and showing two ormore sleep-onset REM periods (SOREMP) onmultiple sleep latency testing (MSLT). In thesepatients, we have found that a good clinical eval-uation often reveals a narrow upper airway asso-ciated with a narrow naso-maxillary complex, and/or a small mandible. The MSLT does show 2 or 3SOREMP and mean sleep latency of 5e8 min.However, nocturnal polysomnogram (PSG) showsabnormalities that unfortunately have not beenincluded in scoring recommendations from theAtlas of the American Academy of Sleep Medicine.On PSG there is intermittent snoring, and the nasalflow pressure transducer shows ‘‘flattening’’ of thepeak of the flow wave contour for an extendedperiod of time particularly during NREM sleep,signifying persistent airflow limitation. During REMsleep there are even greater disturbances withabnormal breathing. Considering the hemoglobineoxyhemoglobin dissociation curve, it is clear thatthe presence of a significant breathing disturbanceis necessary before an oxygen desaturation of 3e4% will take place in children with otherwisenormal lungs, and therefore such oxygen desatu-rations are typically not present. This is mislead-ing and results in inappropriate diagnoses (i.e.,normal study) and recommendations, particularlyif a sleep laboratory transmits raw data to a clini-cian who may not necessarily have experience intreating SDB in children. A common presentationin these pediatric cases is the complaint ofmorning fatigue leading to ‘‘sleeping in’’ onmornings particularly on weekends. This behavioris exaggerated with the onset of puberty. In twoof our clinical cases where saliva was collected

every 90 min from 19:00 to 07:00 h, the peak ofmelatonin secretion was found to be between05:00 and 06:00 h, which was clearly delayedcompared to peers. Appropriate treatment of SDBresolved daytime sleepiness and eliminated SOR-EMP on MSLT. On the other hand, if facing anuncommon presentation it is wise to questiona possible diagnosis of narcolepsy. For example,a female teenager whose only complaint waschronic insomnia, had been unresponsive tohypnotics for 2e3 years, and had difficulty withsleep initiation and maintenance despite the factthat she would feel sleepy by 20:00. She took shortnaps but still experienced daytime fatigue andgave much effort to school attendance. An MSLTcan be somewhat helpful even if not a gold-stan-dard diagnostic test as it may indicate abnormalsleepiness. However, keep in mind that the pres-ence of 2 or 3 SOREMP is not a strong diagnosticcriterion.21,22 As mentioned by the author, cere-brospinal fluid hypocretin measurement is a muchbetter marker and the most definitive tool we havetoday for narcolepsy, and one should consider itwhen in doubt of the diagnosis.

In summary, pediatric sleep disorders covera very important aspect of pediatric medicine. It isvital that we give value to night and daytimesymptoms, are able to recognize underlying causesand initiate appropriate treatment, as sleep-related disorders in the pediatric population havebeen shown to have serious social and health-related consequences now and later on in life.

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110 Guest editorial

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Michelle CaoChristian Guilleminault*

Stanford Sleep Medicine Program, StanfordUniversity Medical School, Stanford, CA, USA

*Corresponding author.E-mail address: cguil@stanford.edu

(C. Guilleminault)