Síndrome de la apnea del sueño en los adultos con síndrome de Down / No disponible

Una elevada proporción de niños con síndrome de Down presentan el síndrome de apnea obstructiva del sueño (SAOS). Aunque los adultos muestran muchos factores de predisposición para tenerlo también, no se ha estudiado el problema en esta población. Nuestra hipótesis es que el SAOS es frecuente en los adultos con síndrome de Down y que su gravedad guarda proporción con el grado de obesidad. Se realizó el estudio en 16 personas adultas con síndrome de Down, de edad entre 19 y 56 años. Los polisomnogramas fueron anormales en el 94% de los sujetos. La mediana del índice de apnea/hipopnea fue de 37 por hora (rango de 0 a 118). La mediana del nadir de la oximetría fue del 75% (23 a 95%), y la mediana de la máxima pCO2 tele-espiratorio fue de 58 (47 a 66) mm Hg. Fue significativa la correlación entre el índice de masa corporal y el índice de apnea/hipopnea. El 63% tuvo una puntuación Epworth superior a 10. El índice de apnea/hipopnea y el nadir de saturación fueron significativamente peores en la población con síndrome de Down que en la control. En conclusión, los adultos con síndrome de Down presentan frecuentemente el síndrome de apnea obstruvctiva del sueño, con apneas obstructivas, hipoxemia, hipoventilación y fragmentación del sueño. La gravedad de este cuadro guarda relación con la obesidad. Puede ser causa de morbilidad en el síndrome de Down y responde al tratamiento (AU)

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Obstructive sleep apnea in adults with Down syndrome.

OBJECTIVES: A high proportion of children with Down syndrome (DS) have the obstructive sleep apnea syndrome (OSAS). Although adults with DS have many predisposing factors for OSAS, this population has not been well studied. We hypothesized that OSAS is common in adults with DS, and that the severity of OSAS is worse in DS adults who are more obese. DESIGN: Cohort study. SETTING: Sleep laboratory. PARTICIPANTS: 16 adults with DS underwent evaluation for sleep disordered breathing. INTERVENTIONS: Polysomnographic results were compared to a retrospective sample of adult patients referred for clinically suspected OSAS. MEASUREMENTS AND RESULTS: Polysomnograms were abnormal in 94% of DS subjects. The median apnea hypopnea index (AHI) was 37/h (range 0-118). The median arterial oxygen saturation nadir was 75% (23% to 95%), and the median peak end-tidal CO2 was 58 (47-66) mm Hg. There was a significant correlation between body mass index and AHI (r = 0.53, p < 0.05). Sixty-three percent had an Epworth score > 10. The AHI and saturation nadir were significantly worse in DS than non-DS patients. CONCLUSIONS: Adults with DS frequently have OSAS, with obstructive apnea, hypoxemia, hypoventilation, and sleep fragmentation. The severity of OSAS correlated with obesity. We speculate that the complications of untreated OSAS (cardiovascular disease, increased mortality, and neurobehavioral morbidities including daytime sleepiness and impaired cognitive function) commonly overlap with the manifestations of DS and therefore may not elicit a prompt investigation in these patients. We speculate that OSAS is an important, but potentially treatable, cause of morbidity in adults with DS.

Respiratory-related evoked potentials during sleep in children.

STUDY OBJECTIVES: The respiratory related evoked potential (RREP) has been previously recorded in children and adults during wakefulness and in adults during sleep. However, there have been no data on RREP during sleep in children. We thus examined children during sleep to determine whether early RREP components would be maintained during all sleep DESIGN AND PARTICIPANTS: Twelve healthy, nonsnoring children, aged 5-12 years, screened by polysomnography and found to have no sleep disorders were assessed during stage 2 sleep, slow wave sleep, and REM sleep. Brief occlusions were presented via an occlusion valve at the inspiratory port of a non-rebreathing valve as interruptions of inspiration. EEG responses were averaged and assessed for the presence of early and late RREP components. RESULTS: Robust early components were seen in the majority of subjects in all sleep stages. Late components were also present, although with some apparent differences compared to those previously reported in adults (using the same recording protocol and an almost identical method of stimulus presentation). Specifically, N350 and N550 were less readily differentiated as separate components, and the N550 did not display the clear anterior-posterior amplitude gradient that is ubiquitous in adults. CONCLUSION: Cortical processing of respiratory-related information persists throughout sleep in children. The pattern of activation in the late components appear to reflect differences in the structure of the developing brain prior to the process of dendritic pruning associated with adolescence.

Adherence to and effectiveness of positive airway pressure therapy in children with obstructive sleep apnea.

OBJECTIVES: Positive airway pressure therapy (PAP) is frequently used to treat children who have obstructive sleep apnea syndrome and do not respond to adenotonsillectomy. However, no studies have evaluated objectively adherence to PAP in children, and few studies have evaluated objectively the effectiveness of PAP. The objective of this study was to determine adherence and effectiveness of PAP (both continuous [CPAP] and bilevel [BPAP] pressure) in children with obstructive apnea. METHODS: A prospective, multicenter study was performed of children who were randomly assigned in a double-blind manner to 6 months of CPAP versus BPAP. Adherence was measured objectively using the equipment's computerized output. Effectiveness was evaluated using polysomnography. RESULTS: Twenty-nine children were studied. Approximately one third of children dropped out before 6 months. Of the 21 children for whom 6-month adherence data could be downloaded, the mean nightly use was 5.3 +/- 2.5 (SD) hours. Parental assessment of PAP use considerably overestimated actual use. PAP was highly effective, with a reduction in the apnea hypopnea index from 27 +/- 32 to 3 +/- 5/hour, and an improvement in arterial oxygen saturation nadir from 77 +/- 17% to 89 +/- 6%. Results were similar for children who received CPAP versus BPAP. Children also had a subjective improvement in daytime sleepiness. CONCLUSIONS: Both CPAP and BPAP are highly efficacious in pediatric obstructive apnea. However, treatment with PAP is associated with a high dropout rate, and even in the adherent children, nightly use is suboptimal considering the long sleep hours in children.

Acoustic arousal responses in children with obstructive sleep apnea.

Our objectives were to study the arousal responses to nonrespiratory (acoustic) stimuli in children with obstructive sleep apnea syndrome (OSAS). The acoustic arousal response was studied in children with OSAS due to adenotonsillar hypertrophy compared to normal, age-matched children. Acoustic stimuli were delivered incrementally from 30-100 dB during stage 2, slow wave sleep, and rapid eye movement (REM) sleep. The percentage of children who aroused in response to acoustic stimuli, and the arousal threshold (i.e., sound level at which arousal occurred), were compared between groups and sleep stages. The percentage of children who aroused was similar between children with OSAS and controls. The percentage of children who aroused was lower during slow wave sleep than REM sleep and stage 2 in both OSAS and controls. There were no statistically significant differences in acoustic arousal threshold between OSAS and control children. There was no difference in arousal response to moderate acoustic stimulation between children with OSAS and controls. These results contrast with previous data showing blunted arousal responses to hypercapnia and upper airway loading during sleep in children with OSAS, suggesting that children with OSAS have an arousal deficit specific to respiratory stimuli. However, further studies evaluating arousal to both respiratory and nonrespiratory stimuli in the same subjects are needed.

Upper airway dynamic responses in children with the obstructive sleep apnea syndrome.

Normal children have a smaller upper airway than adults, but, nevertheless, snore less and have less apnea. We have previously shown that normal children have an upper airway that is resistant to collapse during sleep. We hypothesized that this resistance to collapse is due to preservation of upper airway neuromotor responses during sleep. Furthermore, we hypothesized that upper airway responses would be diminished in children with the obstructive sleep apnea syndrome (OSAS). We therefore compared the upper airway pressure-flow relationship during sleep between children with OSAS and controls. Measurements were made by correlating maximal inspiratory airflow with the level of nasal pressure applied via a mask. Neuromotor upper airway activation was assessed by evaluating the upper airway response to 1) hypercapnia and 2) intermittent, acute negative pressure. We found that children with OSAS had no significant response to either hypercapnia or negative pressure during sleep, compared with the normal children. After treatment of OSAS by tonsillectomy and adenoidectomy, there was a trend for normalization of upper airway responses. We conclude that upper airway dynamic responses are decreased in children with OSAS but recover after treatment. We speculate that the pharyngeal airway neuromotor responses present in normal children are a compensatory response for a relatively narrow upper airway. Further, we speculate that this compensatory response is lacking in children with OSAS, most likely due to either habituation to chronic respiratory abnormalities during sleep or to mechanical damage to the upper airway.

Reliability of scoring arousals in normal children and children with obstructive sleep apnea syndrome.

STUDY OBJECTIVES: Scoring of arousals in children is based on an extension of adult criteria, as defined by the American Sleep Disorders Association (ASDA). By this, a minimum duration of 3 seconds is required. A few recent studies utilized modified criteria for the study of children, with durations as short as 1 second. However, the validity and reliability of scoring these shorter arousals have never been verified. Based on studies in adults, we hypothesized that interscorer agreement for scoring arousals shorter than 3 seconds was poor. DESIGN: Retrospective review of polysomnograms by 2 experienced sleep practitioners who independently scored arousals according to the ASDA 3-second criteria and modified duration criteria of 1 and 2 seconds. SETTING: Academic hospital. PATIENTS OR PARTICIPANTS: 20 polysomnographic studies from children aged 3 to 8 years with mild to severe obstructive sleep apnea syndrome, and 16 polysomnographic studies from normal children. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: The intraclass correlation coefficient for scoring ASDA arousals was 0.90 (95% confidence interval: 0.81-0.95), indicating excellent interscorer agreement. The intraclass correlation coefficient for scoring modified 1-second and 2-second arousals were 0.35 (95% confidence interval: 0.02-0.61) and 0.42 (95% confidence interval: 0.12-0.65) respectively, indicating poor to fair interscorer agreement. Furthermore, modified 1-second and 2-second arousals accounted for less than 15% of all arousals scored. CONCLUSIONS: We conclude that there is much poorer interscorer agreement for scoring arousals shorter than 3 seconds, when compared to the standard ASDA criteria. We propose that scoring of arousals in children should follow the standard ASDA criteria.

Daytime sleepiness and hyperactivity in children with suspected sleep-disordered breathing.

OBJECTIVES: Excessive daytime sleepiness (EDS) is seen less frequently as a presenting complaint in children with sleep-disordered breathing than in adults. Instead, symptoms of hyperactivity are often described. We hypothesized that children with suspected sleep-disordered breathing (S-SDB) were both sleepier and more hyperactive than control subjects. Furthermore, we hypothesized that overnight polysomnographic parameters correlated with sleepiness and hyperactivity. METHODS: A cross-sectional study was conducted at a university-affiliated hospital and a community-based pediatric clinic. A total of 108 patients with S-SDB (mean [standard deviation] age: 7 +/- 4 years) and 72 control subjects (8 +/- 4 years) were recruited. A modified Epworth Sleepiness Scale (ESS) and the Conners Abbreviated Symptom Questionnaire were administered. Polysomnography was performed in patients with S-SDB. RESULTS: Patients with S-SDB had a higher ESS (8.1 +/- 4.9 vs 5.3 +/- 3.9) and a higher Conners score (12.8 +/- 7.6 vs 9.0 +/- 6.2) than control subjects. On the basis of adult criteria, 28% of patients had EDS. There was no difference in the ESS and Conners scores of patients with primary snoring and patients with obstructive sleep apnea. The ESS had weak correlations with polysomnographic parameters. CONCLUSIONS: Although the ESS score of children with S-SDB was within the normal range for adults, these children were sleepier and more hyperactive than control subjects. However, these data should be confirmed by a population-based study.

Developmental changes in upper airway dynamics.

Normal children have a less collapsible upper airway in response to subatmospheric pressure administration (P(NEG)) during sleep than normal adults do, and this upper airway response appears to be modulated by the central ventilatory drive. Children have a greater ventilatory drive than adults. We, therefore, hypothesized that children have increased neuromotor activation of their pharyngeal airway during sleep compared with adults. As infants have few obstructive apneas during sleep, we hypothesized that infants would have an upper airway that was resistant to collapse. We, therefore, compared the upper airway pressure-flow (V) relationship during sleep between normal infants, prepubertal children, and adults. We evaluated the upper airway response to 1). intermittent, acute P(NEG) (infants, children, and adults), and 2). hypercapnia (children and adults). We found that adults had a more collapsible upper airway during sleep than either infants or children. The children exhibited a vigorous response to both P(NEG) and hypercapnia during sleep (P < 0.01), whereas adults had no significant change. Infants had an airway that was resistant to collapse and showed a very rapid response to P(NEG). We conclude that the upper airway is resistant to collapse during sleep in infants and children. Normal children have preservation of upper airway responses to P(NEG) and hypercapnia during sleep, whereas responses are diminished in adults. Infants appear to have a different pattern of upper airway activation than older children. We speculate that the pharyngeal airway responses present in normal children are a compensatory response for a relatively narrow upper airway.

Pulse transit time as a measure of arousal and respiratory effort in children with sleep-disordered breathing.

The upper airway resistance syndrome (UARS) is associated with neurobehavioral morbidity in children. The diagnostic gold standard for UARS is esophageal manometry. However, this is invasive. Furthermore, upper airway obstructive events in sleeping children frequently terminate without visible electrocortical (EEG) arousal. The pulse transit time (PTT) is a noninvasive marker of blood pressure and, therefore, subcortical arousal. Blood pressure elevation, associated with respiratory arousal from sleep, results in a drop in the PTT. We hypothesized that: 1) the PTT is a more sensitive measure of respiratory arousal than EEG; and 2) the PTT arousal index can distinguish children with UARS from those with primary snoring. Polysomnography, including esophageal manometry and PTT, was measured prospectively in 24 symptomatic children and 10 normal controls. Apnea, hypopnea, and respiratory effort-related arousal events terminated in a PTT arousal 91%, 83%, and 80% of the time, and in an EEG arousal in 55%, 51%, and 43% (all p < 0.05), respectively. The PTT arousal index was significantly greater in children with UARS (6.8 events/h) than primary snoring (2.2 events/h) (p < 0.05). We conclude that, in children, PTT arousals are a more sensitive measure of obstructive events than visible EEG arousals.

Secondary narcolepsy in children with brain tumors.

We report two cases of children with disabling daytime sleepiness associated with suprasellar tumors and hypothalamic obesity. Multiple sleep latency testing demonstrated features consistent with severe narcolepsy, with sleep latencies of 0.25 and 0.75 minutes, and REM latencies of 2.1 and 1.5 minutes, respectively. An additional patient with hypothalamic damage secondary to a brain tumor, who was thought to be in a vegetative state, had features of narcolepsy on polysomnography. All children responded well to treatment with stimulants. We speculate that secondary narcolepsy associated with hypothalamic tumors is due to damage or loss of hypothalamic hypocretin-containing neurons. In view of the good response to treatment, we recommend that all children with excessive daytime sleepiness and hypothalamic damage be evaluated for narcolepsy.