Effects of positive airway pressure therapy on neurobehavioral outcomes in children with obstructive sleep apnea.

RATIONALE: Positive airway pressure therapy is frequently used to treat obstructive sleep apnea in children. However, it is not known whether positive airway pressure therapy results in improvements in the neurobehavioral abnormalities associated with childhood sleep apnea. OBJECTIVES: We hypothesized that positive airway pressure therapy would be associated with improvements in attention, sleepiness, behavior, and quality of life, and that changes would be associated with therapy adherence. METHODS: Neurobehavioral assessments were performed at baseline and after 3 months of positive airway pressure therapy in a heterogeneous group of 52 children and adolescents. MEASUREMENTS AND MAIN RESULTS: Adherence varied widely (mean use, 170 ± 145 [SD] minutes per night). Positive airway pressure therapy was associated with significant improvements in attention deficits (P < 0.001); sleepiness on the Epworth Sleepiness Scale (P < 0.001); behavior (P < 0.001); and caregiver- (P = 0.005) and child- (P < 0.001) reported quality of life. There was a significant correlation between the decrease in Epworth Sleepiness Scale at 3 months and adherence (r = 0.411; P = 0.006), but not between other behavioral outcomes and adherence. Behavioral factors also improved in the subset of children with developmental delays. CONCLUSIONS: These results indicate that, despite suboptimal adherence use, there was significant improvement in neurobehavioral function in children after 3 months of positive airway pressure therapy, even in developmentally delayed children. The implications for improved family, social, and school function are substantial. Clinical trial registered with www.clinicaltrials.gov (NCT 00458406).

Upper airway collapsibility during REM sleep in children with the obstructive sleep apnea syndrome.

STUDY OBJECTIVES: In children, most obstructive events occur during rapid eye movement (REM) sleep. We hypothesized that children with the obstructive sleep apnea syndrome (OSAS), in contrast to age-matched control subjects, would not maintain airflow in the face of an upper airway inspiratory pressure drop during REM sleep. DESIGN: During slow wave sleep (SWS) and REM sleep, we measured airflow, inspiratory time, inspiratory time/total respiratory cycle time, respiratory rate, tidal volume, and minute ventilation at a holding pressure at which flow limitation occurred and at 5 cm H2O below the holding pressure in children with OSAS and in control subjects. SETTING: Sleep laboratory. PARTICIPANTS: Fourteen children with OSAS and 23 normal control subjects. RESULTS: In both sleep states, control subjects were able to maintain airflow, whereas subjects with OSAS preserved airflow in SWS but had a significant decrease in airflow during REM sleep (change in airflow of 18.58 +/- 12.41 mL/s for control subjects vs -44.33 +/- 14.09 mL/s for children with OSAS, P = 0.002). Although tidal volume decreased, patients with OSAS were able to maintain minute ventilation by increasing the respiratory rate and also had an increase in inspiratory time and inspiratory time per total respiratory cycle time CONCLUSION: Children with OSAS do not maintain airflow in the face of upper-airway inspiratory-pressure drops during REM sleep, indicating a more collapsible upper airway, compared with that of control subjects during REM sleep. However, compensatory mechanisms exist to maintain minute ventilation. Local reflexes, central control mechanisms, or both reflexes and control mechanisms need to be further explored to better understand the pathophysiology of this abnormality and the compensation mechanism.

Cortical processing of respiratory afferent stimuli during sleep in children with the obstructive sleep apnea syndrome.

STUDY OBJECTIVES: Children with the obstructive sleep apnea syndrome (OSAS) have blunted upper airway responses to negative pressure, but the underlying cause remains unknown. Cortical processing of respiratory afferent information can be tested by measuring respiratory-related evoked potentials (RREPs). We hypothesized that children with OSAS have blunted RREP responses compared to normal children during sleep. DESIGN: During sleep, RREPs were obtained from EEG electrodes Fz, Cz, Pz during stage 2 sleep, slow wave sleep (SWS), and REM sleep. RREPs were produced with multiple short occlusions of the upper airway. SETTING: Sleep laboratory. PARTICIPANTS: 9 children with OSAS and 12 normal controls. MEASUREMENTS AND RESULTS: Children with OSAS had significantly decreased evoked K-complex production in stage 2 sleep and slow wave sleep and significantly reduced RREP N350 and P900 components in slow wave sleep. There were no significant differences in any of the measured RREP components in stage 2 sleep, and the only REM difference was decreased P2 amplitude. CONCLUSIONS: Results indicate that in children with OSAS, cortical processing of respiratory-related information measured with RREPs persists throughout sleep; however, RREPs during SWS are blunted compared to those seen in control children. Possible causes for this difference include a congenital deficit in neural processing reflective of a predisposition to develop OSAS, or changes in the upper airway rendering the airway less capable of transducing pressure changes following occlusion. Further research is required to evaluate RREPs after effective surgical treatment of OSAS in children, in order to distinguish between these alternatives.

Randomized, double-blind clinical trial of two different modes of positive airway pressure therapy on adherence and efficacy in children.

STUDY OBJECTIVES: To determine the effects of bilevel positive airway pressure with pressure release technology (Bi-Flex) on adherence and efficacy in children and adolescents compared to standard continuous positive airway pressure (CPAP) therapy. We hypothesized that Bi-Flex would result in improved adherence but similar efficacy to CPAP. METHODS: This was a randomized, double-blinded clinical trial. Patients with obstructive sleep apnea were randomized to CPAP or Bi-Flex. Repeat polysomnography was performed on pressure at 3 months. Objective adherence data were obtained at 1 and 3 months. RESULTS: 56 children and adolescents were evaluated. There were no significant differences in the number of nights the device was turned on, or the mean number of minutes used at pressure per night for CPAP vs Bi-Flex (24 ± 6 vs 22 ± 9 nights, and 201 ± 135 vs 185 ± 165 min, respectively, for Month 1). The apnea hypopnea index decreased significantly from 22 ± 21/h to 2 ± 3/h on CPAP (p = 0.005), and 18 ± 15/h to 2 ± 2/h on Bi-Flex (p < 0.0005), but there was no significant difference between groups (p = 0.82 for CPAP vs Bi-Flex). The Epworth Sleepiness Scale decreased from 8 ± 5 to 6 ± 3 on CPAP (p = 0.14), and 10 ± 6 to 5 ± 5 on Bi-Flex (p < 0.0005; p = 0.12 for CPAP vs Bi-Flex). CONCLUSIONS: Both CPAP and Bi-Flex are efficacious in treating children and adolescents with OSAS. However, adherence is suboptimal with both methods. Further research is required to determine ways to improve adherence in the pediatric population.

Predictors of positive airway pressure therapy adherence in children: a prospective study.

STUDY OBJECTIVES: Children with obstructive sleep apnea are increasingly being treated with positive airway pressure (PAP), particularly if they have underlying medical conditions. Although PAP is an effective treatment, its use is challenging due to poor adherence. We hypothesized that demographic, psychosocial, and polysomnographic parameters would be related to PAP adherence. We therefore prospectively collected data potentially pertaining to PAP adherence, and correlated it with PAP use. METHODS: Fifty-six patients and their parents completed a series of psychosocial questionnaires prior to PAP initiation. Objective adherence data were obtained after 1 and 3 months of PAP use. RESULTS: The population was primarily obese; 23% had neurodevelopmental disabilities. PAP adherence varied widely, with PAP being worn 22 ± 8 nights in month-1, but mean use was only 3 ± 3 h/night. The greatest predictor of use was maternal education (p = 0.002 for nights used; p = 0.033 for mean h used/night). Adherence was lower in African American children vs other races (p = 0.021). In the typically developing subgroup, adherence correlated inversely with age. Adherence did not correlate with severity of apnea, pressure levels, or psychosocial parameters other than a correlation between family social support and nights of PAP use in month-3. CONCLUSIONS: PAP adherence in children and adolescents is related primarily to family and demographic factors rather than severity of apnea or measures of psychosocial functioning. Further research is needed to determine the relative contributions of maternal education, socioeconomic status and cultural beliefs to PAP adherence in children, in order to develop better adherence programs.

Upper airway collapsibility and genioglossus activity in adolescents during sleep.

STUDY OBJECTIVES: Obese patients develop obstructive sleep apnea syndrome (OSAS), at least in part because of a narrowed upper airway. However, many obese adolescents do not develop OSAS, despite having a presumably narrower airway. The reasons for this phenomenon are unclear. The authors hypothesized that obese controls have a compensatory neuromuscular response to subatmospheric pressure loads during sleep, making them less likely to develop upper airway collapse. DESIGN: Patients underwent pressure-flow measurements during sleep while wearing intraoral electrodes to measure genioglossal electromyography (EMGgg). Two techniques were applied to decrease nasal pressure (P(N)) to subatmospheric levels, resulting in an activated and relatively hypotonic upper airway. SETTING: Sleep laboratory. PARTICIPANTS: There were 35 obese patients with OSAS, 28 obese controls, and 43 lean controls. RESULTS: In the activated state, the two control groups had a flatter slope of the pressure-flow relationship and a more negative critical closing pressure (less collapsible) than the OSAS group. In the hypotonic state, the lean controls had a flatter slope of the pressure-flow relationship than the OSAS and obese control groups. In the activated state, the slope of EMGgg versus P(N) was greater in the obese control group than in the OSAS or lean control groups (P = 0.002 and P = 0.028, respectively); there were no differences in the hypotonic state. CONCLUSIONS: Obese controls have vigorous upper airway neuromuscular responses during sleep. Upper airway reflexes normally decline during adolescent development. It is speculated that obese adolescents without OSAS maintain protective upper airway reflexes during adolescent development, whereas those who go on to develop OSAS do not.