Prevalence of recurrent otitis media in habitually snoring school-aged children

INTRODUCTION: The pathophysiology of obstructive sleep apnea (OSA) and recurrent otitis media (ROM) is intimately associated with the presence of adenotonsillar hypertrophy in children. However, it remains unclear whether habitually snoring children have a higher prevalence of ROM and whether they require tympanostomy tube placement more frequently. METHODS: Questionnaires collected from parental surveys of 5- to 7-year-old children attending the public schools in Louisville, KY were retrospectively reviewed for the presence of habitual snoring (HS), ROM, and the need for tympanostomy tube insertion. RESULTS: There were 16,321 surveys with complete datasets (51.2% boys; 18.6% African American (AA) with a mean age of 6.2+/-0.7 years). Of these children, 1844 (11.3%) were HS (53% boys; 25.9% AA); and, of these, 827 HS had also a positive history of ROM (44.8%) with a slight predominance in males (55%). In addition, 636 of these children underwent placement of tympanostomy tubes (i.e., 34.4% of all HS and 76.9% of ROM). Among the 14,477 non-snoring children (NS), ROM was reported in 4247 NS children (29.3%; p<0.000001; odds ratio [OR]: 1.95; confidence interval [CI]: 1.77-2.16) of which 57.6% were boys, and 1969 NS with ROM underwent tympanostomy tube placement (i.e., 46.3% of those with ROM and 13.6% of all non-snoring children). Thus, the risk for tympanostomy tube placement was also greater among HS compared to NS children (p<0.00001; OR: 2.19; CI: 1.98-2.43). CONCLUSIONS: Habitual snoring is associated with a significant increase in the prevalence of recurrent otitis media and the need for tympanostomy tube placement. Further studies aiming to assess the prevalence of obstructive sleep apnea among children with ROM are needed.     

Sleep architecture in school-aged children with primary snoring

ObjectiveWe aimed to examine if sleep architecture was altered in school-aged children with primary snoring (PS).MethodsChildren ages 6 to 13 years from 13 primary schools were randomly recruited. A validated obstructive sleep apnea (OSA) screening questionnaire was completed by their parents. Children at high risk for OSA and a randomly chosen low-risk group were invited to undergo overnight polysomnography (PSG) and clinical examination. Participants were classified into healthy controls, PS, mild OSA, and moderate to severe OSA (MS OSA) groups for comparison.ResultsA total of 619 participants underwent PSG (mean age, 10.0 ± 1.8 years; 396 (64.0%) boys; 524 (84.7%) prepubertal). For the cohort as a whole, there were no significant differences in measures of sleep architecture between PS and nonsnoring healthy controls. In the multiple regression model, percentage of nonrapid eye movement (NREM) stage 1 (N1) sleep had a significantly positive association, whereas percentage of slow-wave sleep (SWS) had a significantly negative association with sleep-disordered breathing (SDB) severity after controlling for age, gender, body mass index (BMI) z score, and pubertal status. In prepubertal children with PS, no significant disruption of sleep architecture was found. However, pubertal adolescent PS participants had significantly higher adjusted percentage of N1 sleep and wake after sleep onset (WASO) compared to healthy controls.ConclusionsPS did not exert significant adverse influences on normal sleep architecture in prepubertal school-aged children. Nevertheless, pubertal adolescents with PS had increased N1 sleep and WASO.     

Total durations of respiratory events are modulated within REM and NREM sleep by sleeping position and obesity in OSA patients

BackgroundSupine sleeping position and obesity are well-known risk factors for obstructive sleep apnea (OSA) and modulate the risk for OSA-related daytime symptoms. Although respiratory event durations are associated with OSA-related severe health consequences, it is unclear how sleeping position, obesity, and daytime sleepiness are associated with respiratory event durations during REM and NREM sleep. We hypothesize that irrespective of the apnea-hypopnea index (AHI), respiratory event durations differ significantly between various OSA subgroups during REM and NREM sleep.MethodsOne night in-lab polysomnographic recordings were retrospectively analyzed from 1910 untreated suspected OSA patients. 599 patients (AHI ≥ 5) were included in study and divided into subgroups based on positional dependency, BMI, and daytime sleepiness (Epworth Sleepiness Scale and Multiple Sleep Latency Test). Differences in total hypopnea time (THT), total apnea time (TAT), and total apnea-hypopnea time (TAHT) within REM and NREM sleep between the subgroups were evaluated.ResultsDuring REM sleep, positional OSA patients had lower THT (OR = 0.952, p < 0.001) and TAHT (OR = 0.943, p < 0.001) than their non-positional counterparts. Compared to normal-weight patients (BMI < 25 kg/m²), obese patients (BMI ≥ 30 kg/m²) had lower THT, TAT, and TAHT (ORs = 0.942–0.971, p ≤ 0.009) during NREM sleep but higher THT (OR = 1.057, p = 0.001) and TAHT (OR = 1.052, p = 0.001) during REM sleep. No significant differences were observed in THT, TAT, and TAHT between patients with and without daytime sleepiness.ConclusionRegardless of the AHI, respiratory event durations vary significantly between OSA sub-groups during REM and NREM sleep. Therefore, to personalize OSA severity estimation the diagnosis should be tailored based on patient's demographics, clinical phenotype, and PSG characteristics.     

Nocturnal polysomnographic characteristics of habitually snoring children initially referred to pediatric ENT or sleep clinics

ObjectivesTo determine clinical and polysomnographic characteristics of children initially referred by primary care physicians (PCP) to either otolaryngology or sleep clinics for a history of habitual snoring.MethodsRetrospective review of clinical characteristics and nocturnal polysomnograms (PSG) of snoring children referred initially to otolaryngologists by PCP (i.e., ENT) compared to a cross matched population of snoring children initially referred to a pediatric sleep center (i.e., SLEEP).ResultsSixty-eight ENT referred children were cross-matched to 68 SLEEP children. ENT referred children were found to have significantly larger tonsillar size compared to SLEEP children (tonsil size score 3.1 vs. 2.5, p value <0.01). Despite larger tonsillar size, there were no differences observed in the number of children with clinically significant obstructive sleep apnea syndrome (OSAS) with an obstructive apnea hypopnea index (OAHI) ? 5/h TST (40 ENT vs. 38 SLEEP children). Furthermore, SLEEP children with OSAS exhibited more severe sleep related breathing disturbances compared to ENT children (obstructive apnea index: 5.0 vs. 1.5 /h TST, p value <0.01; mean oxygen saturation nadir [76.3% vs. 87.0%, p < 0.01]). Finally, in 28 ENT referred children vs. 30 SLEEP the OAHI was <5/h TST.ConclusionsChildren referred by ENT are not more likely to be diagnosed with OSAS than snoring children directly referred to a pediatric sleep clinic by their pediatricians. The only difference in the referral decision between ENT and SLEEP seems to be tonsil size. Furthermore, PSG revealed a large percentage of children in whom surgical indication for AT is not obvious, thus suggesting that PSG is useful in determining the management of snoring children initially referred to ENT. Finally, SLEEP referred children diagnosed with OSAS exhibited increased indices among selected parameters indicative of sleep-disordered breathing.     

Shift in cognitive asymmetries between wakings from REM and NREM sleep

Twelve subjects were awakened from REM and NREM sleep and tested on three tests designed to measure functions attributed to the left cerebral hemisphere and three tests designed to measure right hemisphere function. A significant shift in cognitive profile was found in the direction of tasks attributed to left hemisphere performance following waking from NREM sleep relative to waking from REM sleep. These results are consistent with the observed reciprocal oscillations between left and right functions during the waking period and imply that performance of these specialized functions may be controlled by some of the same mechanisms thatgovern biorhythms.     

Memory retention of stimulations during REM and NREM stages of sleep.

In 51 normal young female subjects, stimulation by name calling or by intermittent photic stimulation was given during sleep. At different intervals after the stimulation, the subject was awakened and asked if she could recall it. If alpha activity had not been elicited by the stimulus, there was no recall. If the time occupied by alpha activity evoked by the stimulation was more than 30 sec, the stimulus could be recalled after a long period of sleep. When the evoked alpha activity lasted for less than 30 sec and the subject slept again, the longer the evoked alpha activity, the longer the sleeping time span with the memory retention of the preceding stimulation. With equal durations of evoked alpha activity, retention of the stimulus was better when the sleep following was REM stage than when it was NREM stage (stage 2). The results might be explained by the assumption that process of consolidation takes place most rapidly during wakefulness and is inhibited during sleep but to a lesser degree during REM stage than during NREM stage (stage 2).     

Diurnal variations in REM and NREM sleep EEG power spectra in the rat

Diurnal variations were observed in the EEG power spectra of REM sleep and non-REM (NREM) sleep in the rat. Diurnal variations occured in peak EEG frequency and spectral power (0–27 Hz and 5–9 Hz bands) during REM sleep. During NREM sleep diurnal variations were observed in spectral power in the 0–27 Hz and 0–4 Hz bands. The significance of these findings is discussed in terms of correlative data involving diurnal variations in neurotransmitters and hormones, all of which have been implicated in the induction or maintenance of sleep states.     

REM and NREM sleep as natural accompaniments of the evolution of warm-bloodedness

Divergence of primitive sleep into REM and NREM states is thought to have occurred in the nocturnal Triassic ancestors of mammals as a natural accompaniment of the evolution of warm-bloodedness. As ambient temperatures during twilight portions of primitive sleep traversed these evolving ancestors' core temperature, mechanisms of thermoregulatory control that employ muscle contractions became superfluous. The resulting loss of need for such contractions during twilight sleep led to muscle atonia. With muscle tone absent, selection favored the persistence of the fast waves of nocturnal activity during twilight sleep. Stimulations by these waves reinforce motor circuits at the increasing temperatures of evolving warm-bloodedness without leading to sleep-disturbing muscle contractions. By these and related interlinked adaptations, twilight sleep evolved into REM sleep. The daytime period of sleep became NREM sleep. The evolution of NREM and REM sleep following this scenario has implications for sleep's maintenance processes for long-term memories. During NREM sleep, there is an unsynchronized, uncoordinated stimulation and reinforcement of individual distributed component circuits of consolidated memories by slow wave potentials, a process termed ‘uncoordinated reinforcement’. The corresponding process during REM sleep is the coordinated stimulation and reinforcement of these circuits by fast wave potentials. This action temporally binds the individual component circuit outputs into fully formed memories, a process termed ‘coordinated reinforcement’. Sequential uncoordinated and coordinated reinforcement, that is, NREM followed by REM sleep, emerges as the most effective mechanism of long-term memory maintenance in vertebrates. With the evolution of this two-stage mechanism of long-term memory maintenance, it became adaptive to partition sleep into several NREM-REM cycles, thereby achieving a more lengthy application of the cooperative sequential actions.     

On the distribution of REM and NREM sleep under two benzodiazepines with comparable receptor affinity but different kinetic properties

Two clinical-pharmacological investigations were performed to give a retrospective and explorative record, based on electroencephalographic parameters, of spindle density and REM distribution in the first and second halves of the night under a short-acting (triazolam) and medium-acting (lormetazepam) benzodiazepine. A further aim was to determine whether a suitable dose of a short-acting benzodiazepine could lead to a REM suppression in the first sleep cycles and a REM compensation in later sleep cycles on the same night. Since sleep spindles are increased and rapid eye movements reduced under benzodiazepines, the two phenomena were respectively taken as indicators of drug effects on NREM and REM sleep. According to the receptor affinity of the two substances, dosages of triazolam and lormetazepam ought to be equieffective in a ratio of about 1:2. Yet clinical experience has shown that a ratio of 1:4 (0.5 mg triazolam vs. 2 mg lormetazepam) gives the doses that are equieffective and which are widely used in clinical practice. The changes in the number of sleep spindles and rapid eye movements documented the different kinetic properties of the two substances. Even after clinically equieffective doses, the changes in the parameters were less marked under lormetazepam than under triazolam. This suggests that the two benzodiazepines different effects on spindle and REM distribution were not attributable to their kinetics, but that pharmacodynamic aspects must also be considered, even if this does not fit in with the prevalent picture of the benzodiazepines mechanisms of action.(ABSTRACT TRUNCATED AT 250 WORDS)     

Diagnostic accuracy of the Spanish version of the Pediatric Sleep Questionnaire for screening of obstructive sleep apnea in habitually snoring children

ObjectivesWe aimed to determine the diagnostic test accuracy of the Spanish version of the respiratory symptoms scale of the Pediatric Sleep Questionnaire (PSQ) in habitually snoring children for identifying obstructive sleep apnea (OSA).MethodsHabitually snoring children referred for polysomnography (PSG) were recruited. Parents answered the PSQ prior to PSG. Based on an apnea–hypopnea index (AHI) >1.0 in PSG, children were divided into OSA and primary snorers. Correlations to PSG indices and diagnostic test accuracy measures were calculated.ResultsOf the 83 (n = 53 males, mean age 9.5 ± 3.6 years) habitually snoring children included, 35 had OSA. The previously validated PSQ cutoff value of 0.33 showed a specificity of 0.72 and sensitivity of 0.78. The PSQ score correlated significantly with the AHI r_s = 0.313 (p-value = 0.004). Six items of the PSQ were significantly different between cases and controls. A subscale constructed on these six PSQ items concerning respiratory symptoms showed a good sensitivity (0.886) and an excellent negative likelihood ratio (0.261). PSQ was able to identify 89% of the children with OSA correctly.ConclusionsThis version of the PSQ was able to identify children with OSA, separating them from those with primary snoring. The use of this simple, standardized questionnaire tool seems to be helpful and may improve clinical decision making in habitually snoring children.     

Dream experience during REM and NREM sleep of patients with complex partial seizures

This study examined the effectiveness of the cognitive processes underlying dreaming in patients with complex partial seizures (CPS), by assessing the frequency of recall and the structural organization of dreams reported after awakenings provoked alternately during REM and stage 2 NREM sleep on 12 cognitively unimpaired CPS-patients (six with epileptic focus in the right hemisphere and six in the left one). Each patient was recorded for three consecutive nights, respectively, for adaptation to the sleep laboratory context, for polysomnography and for dream collection. The frequency of dream recall was lower after stage 2 NREM sleep than REM sleep, regardless of the side of epileptic focus, while the length and structural organization of dreams did not significantly differ in REM and NREM sleep. However, the length of story-like dreams was influenced by global cognitive functioning during REM sleep. These findings indicate that in CPSs-patients the elaboration of dream experience is maintained in both REM and NREM sleep, while the access to information for conversion into dream contents and the consolidation of dream contents is much less effective during NREM rather than during REM sleep. Further studies may distinguish between these two possibilities and enlighten us as to whether the impaired memory functioning during NREM sleep is a side effect of anticonvulsant treatment.     

Absence of REM and altered NREM sleep in patients with spinocerebellar degeneration and slow saccades

The pontine tegmentum contains the neurons responsible for generation of saccadic eye movements and certain phases of sleep. We studied two genetically unrelated patients with spinocerebellar degeneration and slow saccadic eye movements. Multiple all-night sleep studies in both patients disclosed absence of REM and stage 4 sleep with an extremly short stage 3 and long stage 2. Both patients had a sleep stage (X) not previously reported. These are the first awake and ambulatory humans in whom consistent abscence of REM sleep has been demonstrated. Both behaved appropriately during wakefulness and showed no overt psychological abnormalities.     

Auditory arousal responses and thresholds during REM and NREM sleep of sleepwalkers and controls

BackgroundIt has been suggested that sleepwalkers are more difficult to awaken from sleep than are controls. However, no quantified comparisons have been made between these two populations. The main goal of this study was to assess arousal responsiveness via the presentation of auditory stimuli (AS) in sleepwalkers and controls during normal sleep and recovery sleep following sleep deprivation.MethodsTen adult sleepwalkers and 10 age-matched control subjects were investigated. After a screening night, participants were presented with AS during slow-wave sleep (SWS), REM, and stage 2 sleep either during normal sleep or daytime recovery sleep following 25 h of sleep deprivation. The AS conditions were then reversed one week later.ResultsWhen compared to controls sleepwalkers necessitated a significantly higher mean AS intensity (in dB) to induce awakenings and arousal responses during REM sleep whereas the two groups’ mean values did not differ significantly during SWS and stage 2 sleep. Moreover, when compared to controls sleepwalkers had a significantly lower mean percentage of AS that induced arousal responses during REM sleep while the opposite pattern of results was found during SWS.ConclusionsThe data indicate that sleepwalkers have a higher auditory awakening threshold than controls, but only for REM sleep. These findings may reflect a compensatory mechanism of the homeostatic process underlying sleep regulation during sleepwalkers’ REM sleep in reaction to their difficulties maintaining consolidated periods of NREM sleep.     

Influence of age on the interrelation between EEG frequency bands during NREM and REM sleep

The age-dependence of temporal interrelations between distinct frequency bands of sleep EEG was investigated in a group of 59 healthy young and middle-aged males via cross correlation analysis. Based on global evaluation throughout the entire night, a highly significant decline of the delta/theta correlation with increasing age was found. A separate analysis for non-rapid eye movement (NREM) and rapid eye movement (REM) sleep revealed different changes with aging. During NREM sleep, the correlation between the delta and theta frequency bands decreased with increasing age. In contrast, during REM sleep, a stronger correlation became obvious between the theta, alpha, and beta frequency bands with increasing age, whereas the lower frequency components were not affected. These findings indicate that aging processes seem to interact with sleep EEG rhythms in a complex manner, where most conspicuous is a disintegration of the activities in the lower frequency range, both concerning the successive sleep cycles across the night and the micro-structure of NREM sleep.     

Relationships between REM and NREM in the NREM-REM sleep cycle: a review on competing concepts

Sixty-five years after the discovery of rapid eye movement (REM) sleep, the reasons why we sleep and why we need two states of sleep are still largely unclear. Moreover, the functional relationship between the two types of sleep remains the matter of much conjecture. Several questions come to mind. How does sleep regulation in monophasic and polyphasic animals compare? What are the circadian and homeostatic influences on both states? Are non-rapid eye movement (NREM) and REM states dependent on each other, or are they regulated independently? What about long-term and short-term regulation? In addition, what determines the number and duration of cycles per night? What roles are played by temperature and energy allocation? The evidence collected over the years regarding these questions is summarized here, trying to address each issue.     

A four year follow-up of sleep and respiratory measures in elementary school-aged children with sleep disordered breathing

ObjectiveLittle is known of the long-term prognosis of children treated for sleep disordered breathing (SDB) and even less of children with milder forms of SDB who remain untreated. We aimed to investigate the long-term sleep and respiratory outcomes of children with a range of SDB severities.Methods41 children with SDB and 20 non snoring controls (mean age, 12.9 ± 0.2 y), underwent repeat overnight polysomnography (PSG) 4.0 ± 0.3 years after initial diagnosis. SDB severity, presence of snoring, sleep and respiratory parameters, sleep fragmentation index (SFI), the Pediatric Daytime Sleepiness Scale (PDSS), Sleep Disturbance Scale for Children (SDSC), and obstructive sleep apnea 18-item quality of life questionnaire were re assessed. Children with SDB were grouped into resolved (no snoring and obstructive apnea–hypopnea index [OAHI] <1) and unresolved (snoring or an OAHI ⩾1).ResultsAt follow-up OAHI was reduced in both SDB groups (p < 0.05); however, 54% (n = 22) of children still continued to snore, having either persistent or new OSA (n = 4). In this unresolved group, sleep was significantly disrupted; % nonrapid eye movement stage 1 (NREM1) sleep and SFI were increased (p < 0.05), and total sleep time (TST) and sleep efficiency were decreased compared to the resolved and control groups (p < 0.05). Overall, 29% of children were treated, and of these, 67% had resolved SDB. SDB groups had higher PDSS, SDSC, and OSA-18 scores compared to controls at follow-up (p < 0.01).ConclusionsOur study demonstrated that although SDB improved in the long-term, more than 50% of children had residual SDB (mostly primary snoring) and sleep disturbance. As even mild forms of SDB are known to have adverse cardiovascular, learning, and behavioral outcomes, which have implications for the health of these children.