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Study objectivesChildren with sleep-disordered breathing (SDB) exhibit behavioral, cognitive, and autonomic deficits, suggestive of neural injury. We assessed whether the tissue alterations resulted from acute or chronic processes, and whether alterations correlated with disease severity.MethodsBrain tissue integrity was examined with mean diffusivity (MD) (3.0 T scanner) in 20 nonsnoring controls (mean age ± SEM, 12.2 ± 0.6 years; 10 males) and 18 children with SDB (12.3 ± 0.7 years; 11 males). Sleep, cognitive, and behavioral measures were compared between groups following overnight polysomnography using Student's t tests. Whole-brain MD maps were realigned and averaged, normalized, smoothed, and compared between groups using ANCOVA (covariates: age, gender, and socioeconomic status). Partial correlations were calculated between whole-brain smoothed MD maps and obstructive apnea-hypopnea indices (OAHIs).ResultsAge, gender, and sleep variables did not differ between groups. The SDB group showed higher OAHIs, body mass indices, and systolic blood pressure. Significantly reduced MD values (acute changes) appeared in the hippocampus, insula, thalamus, temporal and occipital cortices, and cerebellum, but were increased (chronic damage) in the frontal and prefrontal cortices in the SDB group over controls. Both positive and negative correlations appeared with extent of tissue changes and disease severity. Externalizing and Total Problem Behaviors were significantly higher in children with SDB. Verbal, performance, and total IQ scores trended lower, and behavioral scores trended higher.ConclusionsPediatric SDB is accompanied by predominantly acute brain changes in areas that regulate autonomic, cognitive, and mood functions, and chronic changes in frontal cortices essential for behavioral control. Interventions need to be keyed to address acute vs chronic injury.

Background and objective: Frequent central apnoeas are sometimes observed in healthy children; however; the pathophysiology of an elevated central apnoea index (CAI) is poorly understood. A raised CAI may indicate underlying ventilatory control instability (i.e. elevated loop gain, LG) or a depressed ventilatory drive. This pilot study aimed to compare LG in otherwise healthy children with an elevated CAI to healthy controls. Methods: Polysomnographic recordings from children (age > 6 months) without obstructive sleep apnoea and with a CAI > 5 events/h (n = 13) were compared with age and gender‐matched controls with a CAI < 5 events/h (n = 13). Spontaneous sighs were identified during non‐rapid eye movement (NREM) sleep, and breath–breath measurements of ventilation were derived from the nasal pressure signal. A standard model of ventilatory control (gain, time constant and delay) was used to calculate LG by transforming ventilatory fluctuations seen in response to a sigh into a ventilatory‐drive signal that best matches observed ventilation. Results: The high CAI group had an elevated LG (median = 0.36 (interquartile range, IQR = 0.35–0.53) vs 0.28 (0.23–0.36); P ≤ 0.01). There was no difference in either the time constant (P = 0.63) or delay (P = 0.29) between groups. Elevated LG observed in the high CAI group remained after accounting for degree of hypoxia (average oxygen saturation (SpO2) during each analysable window) experienced (0.40 (0.30–0.53) vs 0.25 (0.23–0.37); P = 0.04). Conclusion: An elevated CAI in otherwise healthy children is associated with a raised LG compared to matched controls with a low CAI, irrespective of level of hypoxia. This relative ventilatory instability helps explain the high CAI and may ultimately be able to help guide diagnosis and management in patients with high CAI. While central apnoeas are common in children, a central apnoea index of >5 events/h is outside normal ranges and raises concern regarding origins of such events. Our study indicates that an elevated index of >5 is associated with a hypersensitive ventilatory control system and supports literature that neuroimaging may not be needed. [ABSTRACT FROM AUTHOR]

Key points: Sleep disordered breathing (SDB) affects 4–11% of children and is associated with adverse neurocognitive, behavioural and cardiovascular outcomes, including reduced autonomic control.The relationship between heart rate variability (HRV; a measure of autonomic control) and age found in non‐snoring control children was absent during sleep in children with SDB.Age significantly predicted increasing cerebral oxygenation during wake in non‐snoring control children, whereas during sleep, HRV significantly predicted decreasing cerebral oxygenation.Cerebral oxygenation was not associated with either age or HRV in children with SDB during both wake and sleep.SDB significantly disrupts the normal maturation of autonomic control and the positive association between autonomic control and cerebral oxygenation found in non‐snoring children, and we speculate that the dampened autonomic control exhibited by children with SDB may have an attenuating effect on cerebral autoregulation via the moderating influence of HRV on cerebral blood flow. The repetitive episodes of hypoxia that are features of sleep disordered breathing (SDB) in children are associated with alterations in autonomic control of heart rate in an age‐dependent manner. We aimed to relate heart rate variability (HRV) parameters to age and measures of cerebral oxygenation in children (3–12 years old) with SDB and non‐snoring controls. Children (SDB, n = 117; controls, n = 42; 3–12 years) underwent overnight polysomnography. Total (TP), low‐ (LF) and high‐frequency (HF) power, tissue oxygenation index (TOI) and fractional tissue oxygen extraction (FTOE) were analysed during wake and sleep. Pearson's correlations determined the association between age and HRV parameters, and multiple linear regressions between HRV, age and cerebral oxygenation parameters. During wake, age had a positive association with LF power, reflecting increased parasympathetic and sympathetic activity with increasing age for both control and SDB groups. This association was also evident during sleep in controls, but was absent in children with SDB. In controls, during wake TOI had a positive, and FTOE a negative association with age. During sleep, TP, LF and HF power were significant, negative determinants of TOI and positive determinants of FTOE. These associations were not seen in children with SDB during wake or sleep. SDB disrupts the normal maturation of the autonomic control of heart rate and the association between HRV and cerebral oxygenation exhibited by non‐snoring control children of primary school age. These results highlight the impact SDB has on cardiovascular control and the potential impact on adverse cardiovascular outcomes. Key points: Sleep disordered breathing (SDB) affects 4–11% of children and is associated with adverse neurocognitive, behavioural and cardiovascular outcomes, including reduced autonomic control.The relationship between heart rate variability (HRV; a measure of autonomic control) and age found in non‐snoring control children was absent during sleep in children with SDB.Age significantly predicted increasing cerebral oxygenation during wake in non‐snoring control children, whereas during sleep, HRV significantly predicted decreasing cerebral oxygenation.Cerebral oxygenation was not associated with either age or HRV in children with SDB during both wake and sleep.SDB significantly disrupts the normal maturation of autonomic control and the positive association between autonomic control and cerebral oxygenation found in non‐snoring children, and we speculate that the dampened autonomic control exhibited by children with SDB may have an attenuating effect on cerebral autoregulation via the moderating influence of HRV on cerebral blood flow. [ABSTRACT FROM AUTHOR]