Samantha Hollis

Comparison of Commercial Wrist-Based and Smartphone Accelerometers, Actigraphy, and PSG in a Clinical Cohort of Children and Adolescents

STUDY OBJECTIVES To compare two commercial sleep devices, an accelerometer worn as a wristband (UP by Jawbone) and a smartphone application (MotionX 24/7), against polysomnography (PSG) and actigraphy (Actiwatch2) in a clinical pediatric sample. METHODS Children and adolescents (n = 78, 65% male, mean age 8.4 ± 4.0 y) with suspected sleep disordered breathing (SDB), simultaneously wore an actiwatch, a commercial wrist-based device and had a smartphone with a sleep application activated placed near their right shoulder, during their diagnostic PSG. Outcome variables were sleep onset latency (SOL), total sleep time (TST), wake after sleep onset (WASO), and sleep efficiency (SE). Paired comparisons were made between PSG, actigraphy, UP, and MotionX 24/7. Epoch-by-epoch comparisons determined sensitivity, specificity, and accuracy between PSG, actigraphy, and UP. Bland-Altman plots determined level of agreement. Differences in bias between SDB severity and developmental age were assessed. RESULTS No differences in mean TST, WASO, or SE between PSG and actigraphy or PSG and UP were found. Actigraphy overestimated SOL (21 min). MotionX 24/7 underestimated SOL (12 min) and WASO (63 min), and overestimated TST (106 min) and SE (17%). UP showed good sensitivity (0.92) and accuracy (0.86) but poor specificity (0.66) when compared to PSG. Bland-Altman plots showed similar levels of bias in both actigraphy and UP. Bias did not differ by SDB severity, however was affected by age. CONCLUSIONS When compared to PSG, UP was analogous to Actiwatch2 and may have some clinical utility in children with sleep disordered breathing. MotionX 24/7 did not accurately reflect sleep or wake and should be used with caution.

Long-Term Cognitive and Behavioral Outcomes following Resolution of Sleep Disordered Breathing in Preschool Children

This study aimed to determine the long term effects of resolution of SDB in preschool children, either following treatment or spontaneous recovery, on cognition and behavior. Children diagnosed with SDB at 3-5y (N = 35) and non-snoring controls (N = 25), underwent repeat polysomnography (PSG) and cognitive and behavioral assessment 3 years following a baseline study. At follow-up, children with SDB were grouped into Resolved and Unresolved. Resolution was defined as: obstructive apnea hypopnea index (OAHI) ≤1 event/h; no snoring detected on PSG; and no parental report of habitual snoring. 57% (20/35) of children with SDB received treatment, with SDB resolving in 60% (12/20). 43% (15/35) were untreated, of whom 40% (6/15) had spontaneous resolution of SDB. Cognitive reduced between baseline and follow-up, however this was not related to persistent disease, with no difference in cognitive outcomes between Resolved, Unresolved or Control groups. Behavioral functioning remained significantly worse in children originally diagnosed with SDB compared to control children, regardless of resolution. Change in OAHI did not predict cognitive or behavioral outcomes, however a reduction in nocturnal arousals, irrespective of full resolution, was associated with improvement in attention and aggressive behavior. These results suggest that resolution of SDB in preschool children has little effect on cognitive or behavioral outcomes over the long term. The association between sleep fragmentation and behavior appears independent of SDB, however may be moderated by concomitant SDB. This challenges the assumption that treatment of SDB will ameliorate associated cognitive and behavioural deficits and supports the possibility of a SDB phenotype.

Long-term improvements in sleep and respiratory parameters in preschool children following treatment of Sleep Disordered Breathing

STUDY OBJECTIVE Sleep disordered breathing (SDB) in preschool-aged children is common, but long-term outcomes have not been investigated. We aimed to compare sleep and respiratory parameters in preschool children to examine the effects of treatment or non-treatment after 3 years. METHODS Children (3-5 years) diagnosed with SDB (n = 45) and non-snoring controls (n = 30) returned for repeat overnight polysomnography (39% of original cohort), 3 years following baseline polysomnography. Children with SDB were grouped according to whether they had received treatment or not. SDB resolution was defined as an obstructive apnea hypopnea index (OAHI) ≤ 1 event/h, no snoring detected on polysomnography and habitual snoring not indicated by parents on questionnaire. RESULTS Fifty-one percent (n = 23) of the children with SDB were treated. Overall, SDB resolved in 49% (n = 22), either spontaneously (n = 8) or with treatment (n = 14). SDB remained unresolved in 39% (n = 9) of those treated and 64% (n = 14) of the children who were untreated. Two of the non-snoring controls developed SDB at follow-up. The treated group had significantly lower OAHI (p < 0.01), respiratory disturbance index (p < 0.001), total arousal and respiratory arousal indices (p < 0.01 for both) at follow-up compared with baseline. There were no differences between studies for the untreated group. CONCLUSIONS Although treatment resulted in an improvement in indices related to SDB severity, 39% had SDB 3 years following diagnosis. These findings highlight that parents should be made aware of the possibility that SDB may persist or recur several years after treatment. This is relevant regardless of the severity of SDB at baseline and the treatment given.

Fetal-growth-restricted preterm infants display compromised autonomic cardiovascular control on the first postnatal day but not during infancy

BackgroundFetal growth restriction (FGR) is associated with increased perinatal mortality and long-term cardiovascular and neurodevelopmental sequelae. We hypothesized that FGR impacts on the development of autonomic heart rate and blood pressure control, contributing to unfavorable short- and long-term outcomes following FGR.MethodsWe studied 25 preterm FGR and 22 preterm and 19 term appropriate for gestational age (AGA) infants. Preterm neonates were studied on postnatal day 1, and all infants were studied at 1 and 6 months post-term age. To investigate autonomic cardiovascular control, we examined heart rate variability (HRV) and baroreflex sensitivity using spectral power and transfer-function analyses.ResultsPreterm FGR neonates exhibited higher heart rates and reduced HRV compared with preterm AGA controls on postnatal day 1. No significant differences were found between the three groups at 1 or 6 months post-term age.ConclusionPreterm FGR neonates display compromised HRV on postnatal day 1, which may suggest increased vulnerability to circulatory instability. This may predispose these neonates to systemic and cerebral hypoperfusion and increase the risk of long-term neurodevelopmental sequelae. Differences were no longer found at 1 and 6 months post-term age, suggesting that the maturation of autonomic cardiovascular control may be preserved following FGR.

Longitudinal Impact of Resolution of Snoring in Young Children on Psychosocial Functioning.

OBJECTIVE To determine whether sustained resolution of sleep disordered breathing (SDB) in young children, either because of treatment or spontaneous recovery, predicted long-term improvements in quality of life, family functioning, and parental stress. STUDY DESIGN Children diagnosed with primary snoring (n = 16), mild obstructive sleep apnea (OSA, n = 11), moderate-severe (MS) OSA (n = 8), and healthy nonsnoring controls (n = 25) at ages 3-5 years underwent repeat polysomnography at 6-8 years. Parents completed quality of life and parental stress questionnaires at both time points. Resolution of SDB was determined as obstructive apnea hypopnea index (OAHI) ≤1 event/hour, or absence of snoring during polysomnography or on parent report. Linear mixed-model analyses determined the effects of resolution on psychosocial morbidity. OAHI was used to determine the predictive value of changes in SDB severity on psychosocial outcomes. RESULTS Fifty percent of primary snoring, 45% mild OSA, and 63% MS OSA resolved, of which 67% received treatment. Children originally diagnosed with SDB continued to show significant psychosocial impairments compared with nonsnoring controls, irrespective of resolution. A reduction in OAHI predicted improvements in physical symptoms, school functioning, family worry and family relationships, and stress related to a difficult child. CONCLUSIONS Treatment was more likely to result in resolution of SDB if original symptoms were MS. Children originally diagnosed with SDB, irrespective of resolution, continued to experience psychosocial dysfunction suggesting additional interventions are required.

Effects of foetal growth restriction and preterm birth on cardiac morphology and function during infancy

To investigate the effects of foetal growth restriction (FGR) and prematurity on cardiac morphology and function in infancy. We hypothesised that FGR and prematurity would both alter cardiac development.

Association between slow-wave activity, cognition and behaviour in children with sleep-disordered breathing

BACKGROUND It has been suggested that impaired dissipation of slow-wave activity (SWA) in children with sleep-disordered breathing (SDB) may be a potential mechanism for daytime dysfunction. We aimed to examine whether resolution of SDB resulted in normalisation of SWA dissipation and whether this was associated with improved cognition and behaviour. METHODS Children (aged 3-6 y) diagnosed with SDB and age-matched non-snoring control children were followed up for 3 y after a baseline study. At the follow-up, children were categorised into control (N = 13), resolved SDB (N = 15) and unresolved SDB (N = 14). Delta activity on the electroencephalogram over the sleep period was used to calculate SWA and a battery of cognitive assessments and behaviour questionnaires were conducted at both time points. RESULTS There was no change in the average SWA between the baseline and follow-up and no differences between the groups. Cognitive and behavioural performance in the resolved group did not improve to control levels. However, decreased SWA at the beginning of the sleep period (β = -0.04, p = 0.002) and a decrease in obstructive apnoea-hypopnoea index (β = -2.2, p = 0.022) between the baseline and follow-up predicted improvements in measures of sustained attention. Increased SWA at the beginning of the sleep period between the baseline and follow-up predicted worsening of externalising behaviour (β = 0.02, p = 0.039). CONCLUSIONS This study suggests that resolution of SDB is not associated with changes in the dissipation of SWA. However, the association between decreases in SWA and improvements in cognitive and behavioural outcomes suggest that irrespective of disease, children whose quantitative sleepiness improves have improved attention and reduced externalising behaviours.

EEG power spectrum maturation in preterm fetal growth restricted infants

Power spectral analysis of the electroencephalogram (EEG) is a non-invasive method to examine infant brain maturation. Preterm fetal growth restricted (p-FGR) neonates display an altered EEG power spectrum compared to appropriate-for-gestational-age (AGA) peers, suggesting delayed brain maturation. Longitudinal studies investigating EEG power spectrum maturation in p-FGR infants are lacking, however. We thus aimed to investigate brain maturation using sleep EEG power spectral analysis in p-FGR infants compared to preterm and term AGA controls (p-AGA and t-AGA, respectively). EEG was recorded during spontaneous sleep in 13 p-FGR, 17 p-AGA and 19 t-AGA infants at 1 and 6 months post-term age. Infant sleep states (active and quiet sleep) were scored using standard criteria. Power spectral analysis of a single-channel EEG (C3-M2/C4-M1) was performed using Fast Fourier Transform. The EEG power spectrum was divided into delta (0.5-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), sigma (12-14 Hz) and beta (14-30 Hz) frequency bands. Relative (%) powers and the spectral edge frequency were calculated. The spectral edge frequency was significantly higher in p-FGR infants compared to p-AGA controls in quiet sleep at 1 month post-term age (p < .01). This was due to significantly reduced %-delta and significantly increased %-theta, %-alpha and %-beta power (p < .01 for all) compared to p-AGA infants. p-FGR infants also showed significantly increased %-beta power compared to t-AGA infants (p < .05). No group differences were observed in active sleep or at 6 months post-term age. In conclusion, p-FGR infants show altered sleep EEG power spectrum maturation compared to AGA peers. However, changes resolved by 6 months post-term age.

Sleep: A Window Into Autonomic Control in Children Born Preterm and Growth Restricted

Study Objectives Preterm birth and fetal growth restriction (FGR) are both associated with risk of hypertension in adulthood. Mechanisms leading to this pathology are unclear. In children aged 5-12 years, who were born preterm and FGR, we used sleep as a tool to assess autonomic control with assessment of cardiovascular structure and function. Methods Eighteen children born preterm and FGR, 15 children born preterm with appropriate birth weights for gestational age (AGA), and 20 AGA term-born children were studied. Children underwent overnight polysomnography with the addition of continuous noninvasive blood pressure (Finometer™). Spectral measures of heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity were assessed and overnight urinary catecholamine levels measured. Echocardiographic studies (Vivid7, GE Healthcare) were performed and vascular compliance assessed (Miller Instruments™). Statistical comparisons were adjusted for age and body size. Results Compared to term children, preterm AGA children had increased high frequency HRV (p < .05) and BPV (p < .05) during sleep, reflecting increased parasympathetic activation and blood pressure changes related to respiration. Preterm FGR children had smaller left ventricular lengths, ascending aorta, and left ventricular outflow tract diameter (p < .05 for all) and vascular compliance was positively correlated with gestational age (r2 = 0.93, p < .05). Conclusions FGR combined with preterm birth did not alter autonomic control but altered heart structure in children. In contrast, preterm birth alone altered autonomic control but had no change in heart structure. These changes in children born preterm and FGR may contribute, in part, to increased risk of cardiovascular disease later in life but by different mechanisms.

Being Born Too Small and Too Early May Alter Sleep in Childhood

Study Objectives Fetal growth restriction (FGR) occurs in up to 10% of pregnancies and is associated with increased risk of prematurity and neurodevelopmental impairment. FGR also alters sleep state distribution in utero and maturation in infancy. Currently, limited data on the long-term associations of FGR and childhood sleep exist. Accordingly, we assessed the associations between preterm birth and FGR and sleep in children aged 5-12 years. Methods 17 children born preterm and FGR, 15 children born preterm but appropriately grown (AGA) and 20 term AGA children (controls) were studied using overnight polysomnography. Sleep macro-architecture was assessed using standard criteria and sleep micro-architecture was assessed using spectral analysis of the EEG (C4-M1) with Total, Delta (0.5Hz-3.9Hz), Theta (4.0Hz-7.9Hz), Alpha (8.0Hz-11.9Hz), Sigma (12.0Hz-13.9Hz) and Beta Power (14.0Hz-30Hz) calculated. Results For sleep macro-architecture, preterm FGR children had higher N2% compared to term AGA children (p<0.05). Preterm AGA children had reduced total sleep time, NREM% and sleep efficiency compared to term AGA children (p<0.05 for all). For sleep micro-architecture, preterm FGR children had a higher amount of Total, delta and alpha power compared to both groups (p<0.05). Sigma and beta power were lowest in the preterm AGA group compared to both groups (p<0.05 for both). Conclusions Prematurity and FGR were associated with altered sleep macro- and micro-architecture measures indicative of reduced sleep quantity and quality in childhood. As sleep disturbance can impact both behavior and neurodevelopment in children, sleep in FGR and preterm children warrants further investigation.