Original ArticleREM and NREM sleep-state distribution of respiratory events in habitually snoring school-aged community children
Introduction
Substantial discrepancies have emerged among studies examining the clinical characteristics of paediatric sleep-disordered breathing (SDB). Considering the high prevalence of this disorder, as evidenced by a mean in the 10–12% range [1], [2], [3], it is generally believed that the occurrence of respiratory disturbance will be predominantly manifest during rapid eye movement sleep (REMS) when compared to non-rapid eye movement sleep (NREMS) [4], [5]. Moreover, it has been suggested that, in children, sleep architecture is preserved [4] and that body position does not influence frequency nor severity of respiratory events [6], [7], even if such findings have been challenged in the context of concurrent presence of obesity [8], [9].
Hitherto, the most common overnight polysomnographic metric applied to the assessment of the severity of SDB is the apnoea–hypopnea index (AHI). This index reflects a composite score essentially composed by the summation of the number of obstructive and central apnoeic events, and the number of hypopneas per hour of sleep. Tang et al. [10] studied the home-based plethysmography, pulse oximetry, body position, and heart rate parameters of 433 children, ages 8–11 years, who were not referred for clinical assessment of SDB, and concluded that different approaches for quantifying respiratory disturbance indices would contribute to substantial variability in the identification and classification of SDB. Furthermore, their findings were suggestive that central apnoeas in children should be computed and reported separately from obstructive events. In addition, arousals have been recently proposed as an important protective mechanism for termination of an obstructive apnoea event; however, the definition of a respiratory arousal being based on its proximity to a respiratory event should not be mistaken to imply a causal relationship between these two. Independently, the number as well as the duration of arousals may cause sleep fragmentation and disruption of sleep architecture. As a consequence, respiratory events may exert a distinctive impact on sleep integrity, and therefore on daytime well-being.
In adults with obstructive sleep apnoea (OSA) respiratory events occur predominantly during NREMS, and, more recently, this pattern was also reported in up to a third of children with moderate to severe OSA [11]. In other words, the ratio of REMS to NREMS obstructive apnoea–hypopnea index (OAHI) showed an NREMS predominance in older children with higher arousal indices and less severe desaturations with events. Based on the impression that such a pattern was only seldom encountered in our clinical practice, we sought to explore the distribution of REMS and NREMS respiratory events, and analysed potential predictors towards such distribution.
Section snippets
Subjects
The study was approved by the University of Louisville Human Research Committee (Protocol #474.99) and the Boards of the participating schools. Parents were invited to complete the Gozal questionnaire [12], [13], which, in addition to demographic information and information on the significant medical history of the child, included sleep questions concerns difficulty initiating sleep, restless sleep, enuresis, and apnoea, and other questions such as appetite and overall activity. From the
Results
Children were 7.3 ± 1.2 years old (38.6% girls, 57.5% white non-Hispanic [WNH], 29.9% African-American [AA], 12.6% mixed ethnicity [M]) and had a BMI z-score of 1.0 ± 1.3 (2.1% underweight, 5.1% at risk underweight, 42.5% normal weight, 13% overweight and 37.3% obese). OAHI was 1.7 ± 3 h−1 TST (minimum: 0 to maximum: 30.91) and 45.8% of children had AHI >1 h−1 TST. Descriptives of the NPSG can be found in Table 1. In addition, among the covariates the DI ⩾2% was higher in REMS than NREMS (2.6 ± 8.3 h−1 vs.
Discussion
This study shows that respiratory events are 3.8 times more likely to occur in REMS in school-aged children. However, predominance of NREMS respiratory events is not uncommon and occurs in about 1/6 of children. Current findings also suggest that, depending on sleep position, the respiratory event profiles of children are modified and therefore need to be considered as potential confounders in our exploration and understanding of pathophysiological mechanisms and outcomes.
Some methodological
Conflicts of interest
The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: doi:10.1016/j.sleep.2011.04.006.
Acknowledgements
This study was supported by National Institutes of Health Grant HL65270.
We thank Ahmad Shata for his assistance in data management.
References (35)
- et al.
Anatomic determinants of sleep-disordered breathing across the spectrum of clinical and nonclinical male subjects
Chest
(2002) - et al.
Prevalence of habitual snoring and sleep-disordered breathing in preschool-aged children in an Italian community
J Pediatr
(2003) - et al.
Childhood obstructive sleep apnea: one or two distinct disease entities?
Sleep Med Clin
(2007) - et al.
Body position and obstructive sleep apnea in 8–12-month-old infants
Int J Pediatr Otorhinolaryngol
(2008) - et al.
Abbreviated method for assessing upper airway function in obstructive sleep apnea
Chest
(2000) - et al.
Upper airway resistance syndrome in children: a clinical review
Semin Pediatr Neurol
(2001) - et al.
Long-term follow-up and mechanisms of obstructive sleep apnea (OSA) and related syndromes through infancy and childhood
Int J Pediatr Otorhinolaryngol
(2003) - et al.
Sleep-disordered breathing. A view at the beginning of the new Millennium
Dent Clin North Am
(2001) - Standards and indications for cardiopulmonary sleep studies in children. American Thoracic Society. American journal of...
- et al.
Sleep architecture and respiratory disturbances in children with obstructive sleep apnea
Am J Respir Crit Care Med
(2000)
Arousal and ventilatory responses during sleep in children with obstructive sleep apnea
J Appl Physiol
Effect of sleep state and position on the incidence of obstructive and central apnea in infants
Pediatrics
Body position and obstructive sleep apnea in children
Sleep
Nocturnal body position in sleeping children with and without obstructive sleep apnea
Pediatr Pulmonol
Identification of sleep-disordered breathing in children: variation with event definition
Sleep
Sleep state distribution of obstructive events in children: is obstructive sleep apnoea really a rapid eye movement sleep-related condition?
J Sleep Res
Sleep-disordered breathing and school performance in children
Pediatrics
Cited by (31)
The impact of sleep events on weight gain following early adenotonsillectomy compared to supportive care for pediatric OSA
2022, International Journal of Pediatric OtorhinolaryngologyApnea hypopnea indices categorized by REM/NREM sleep and sleep positions in 100 children with adenotonsillectomy for obstructive sleep apnea disease
2019, International Journal of Pediatric OtorhinolaryngologyObstructive events in children with Prader–Willi syndrome occur predominantly during rapid eye movement sleep
2019, Sleep MedicineCitation Excerpt :Obstructive events occur more predominantly in REM than in NREM sleep in approximately 70% of children, and this proportion is affected by sleep position [17,18]. However, the control subjects in this study slept mostly in the supine position, which is characterized by predominance of REM obstructive events over NREM events in approximately 50% of cases [18]. In conclusion, in children with PWS, OAHI calculated for TST underestimates OSAS severity during REM sleep appreciably, which on average can be twice as high.
Considerations in pediatric patients with obstructive sleep apnea/hypopnea syndrome (OSAHS): From physiopathology to the perioperative period
2017, Revista Colombiana de AnestesiologiaSleep-wake control of the upper airway by noradrenergic neurons, with and without intermittent hypoxia
2014, Progress in Brain Research