Toddler behavior following polysomnography: effects of unintended sleep disturbance

The association between infant sleep, cognitive, and psychomotor development: a systematic review

STUDY OBJECTIVES

To synthesize findings of original articles examining the association between sleep-wake patterns of typically developing infants aged 0 to 18 months and cognitive and psychomotor development.

METHODS

A systematic search strategy was used to identify articles assessing the association between infant sleep (0 to 18 months) and cognitive/psychomotor development (Medline, PsycINFO, and SCOPUS). Of 7136 articles screened, 22 articles met inclusion criteria, and the results were subsequently synthesized. A quality assessment was conducted, and studies were categorized as "poor," "fair," or "good."

RESULTS

Out of 22 studies, 2 found exclusively significant associations (SAs) between infant sleep and cognitive/psychomotor development, 2 found no SAs and 17 found mixed results (MRs). Studies with exclusively significant results used a single sleep variable and single timepoint designs. Studies finding MRs or no SAs used multiple sleep, developmental variables, or multi-timepoint designs. Eight out of 10 studies and 7 out of 8 studies investigating nocturnal and total sleep duration, respectively, found no SA with developmental outcomes. While 63% of studies were rated as having good methodological quality, all studies but one had an estimated power of less than 0.80.

CONCLUSIONS

Findings of this review do not support conclusive associations between sleep-wake patterns in infancy and cognitive/psychomotor development. This conclusion contrasts with the literature in older populations, questioning if the association between sleep and development is of a different nature in infancy, potentially because of brain maturation. More studies including larger samples will be needed to clarify the presence or absence of such an association.

Associations between parent-reported and objectively measured sleep duration and timing in infants at age 6 months

STUDY OBJECTIVES

To compare the estimates of sleep duration and timing from survey, diary, and actigraphy in infants at age 6 months, overall and by select demographics and other factors.

METHODS

In total, 314 infants participating in the Rise & SHINE (Sleep Health in Infancy & Early Childhood study) cohort in Boston, MA, USA, wore an actigraph on their left ankle for 7 days. Parents concurrently completed a sleep diary and the expanded version of the Brief Infant Sleep Questionnaire. Concordance between parent-reported and objective sleep estimates was assessed using Bland-Altman plots, Spearman's rank correlations, intraclass correlations, and linear regression models.

RESULTS

Mean infant age was 6.4 (0.6 SD) months; 51% were female and 42% were Non-Hispanic white. Mean total sleep duration using actigraphy was 526 (67 SD) minutes per night, 143 (42 SD) minutes per day, and 460 (100 SD) minutes during the longest nighttime sleep period. Relative to actigraphy, parent-completed survey and diary overestimated total day (by 29 and 31 minutes, respectively) and night sleep duration (67 and 43 minutes, respectively) and underestimated the longest sleep (58 minutes), with the highest agreement for sleep onset and offset timing (differences < 30 minutes). There was a tendency toward greater bias among short- and long-sleeping infants. Self-reporting bias for diary-measured longest nighttime sleep and total night sleep duration was higher in infants of parents reporting a problem with their baby's night awakenings and in low-income families, respectively.

CONCLUSIONS

Our findings underscore the need to be cautious when comparing findings across studies using different sleep assessment methods.

What do preschool-aged children do when they wake at night: toward an understanding of night-waking behaviors among community children

Little is known about behaviors displayed by preschoolers during night-waking. Mothers (N = 203) of community preschoolers completed the Children's Night-waking Behavior Scale and measures of night-waking, co-sleeping, and daytime behavior. Approximately 1/2 of wakings involved calling out, getting out of bed, and requests for comfort; 1/4 involved activity, fear, or instrumental requests. Specific associations between night-waking behaviors, night-waking, and bedtime and daytime behaviors were observed; associations were not consistent across child gender and age. For example, comfort requests were associated with mothers' perceptions of sleep as problematic in 4- and 5-year-old children only (ρ = .42); activity requests were associated with hyperactivity for boys only (r = .36). Understanding night-waking requires consideration of factors beyond parenting, such as children's behavior, age, and gender.

Gastroesophageal reflux causing sleep interruptions in infants

BACKGROUND AND AIM

Little is known about the relation between gastroesophageal reflux (GER) episodes and sleep interruptions in infants. The aim of the study was to evaluate the relationship between GER and the incidence of sleep interruptions in infants.

METHODS

Study patients included 24 infants (younger than 1 year) referred for multichannel intraluminal impedance and esophageal pH monitoring with simultaneous polysomnography. Exclusion criteria were a previous fundoplication and studies lasting <20 hours. Tests were clinically indicated to investigate suspicion of GER-related apnea (17, 70.8%), stridor (6, 25%), noisy breathing (2, 8.3%), and cyanotic spells (1, 4.2%). Most patients presented with significant comorbidities (19, 79.2%).

RESULTS

The number of nonacid GER (NAGER) per hour was greater during sleep time than during daytime and awakening following sleep onset (median 0.27 vs 1.85 and 1.45, P<0.01). A total of 1204 (range 7-86 per infant) arousals in 24 infants was detected, 165 (13.7%) that followed GER episodes, and 43 (3.6%) that preceded GER episodes. Seven patients presented with a positive symptom association probability for arousals; 5 were exclusively because of NAGER. A positive symptom association probability for awakenings was detected in 9 patients; 4 were because of NAGER, 4 were because of AGER, and 1 was because of both NAGER and GER. Patients with awakenings related to GER presented longer mean clearance time of AGER during sleep (165.5 vs 92.8 seconds, P=0.03).

CONCLUSIONS

GER was a frequent cause of interrupting sleep among our infant patients, and NAGER proved to be equally important as AGER for causing arousals and awakenings in infants.

Use of actigraphy for assessment in pediatric sleep research

The use of actigraphs, or ambulatory devices that estimate sleep-wake patterns from activity levels, has become common in pediatric research. Actigraphy provides a more objective measure than parent-report, and has gained popularity due to its ability to measure sleep-wake patterns for extended periods of time in the child's natural environment. The purpose of this review is: 1) to provide comprehensive information on the historic and current uses of actigraphy in pediatric sleep research; 2) to review how actigraphy has been validated among pediatric populations; and 3) offer recommendations for methodological areas that should be included in all studies that utilize actigraphy, including the definition and scoring of variables commonly reported. The poor specificity to detect wake after sleep onset was consistently noted across devices and age groups, thus raising concerns about what is an "acceptable" level of specificity for actigraphy. Other notable findings from this review include the lack of standard scoring rules or variable definitions. Suggestions for the use and reporting of actigraphy in pediatric research are provided.

Sleep, sleep-disordered breathing and lipid homeostasis: translational evidence from murine models and children

Impaired sleep, particularly in the context of sleep-disordered breathing (SDB), is associated with a vast array of comorbidities, including obesity. It is well known that the etiology of obesity is both complex and multifactorial. Recent trends have shown that obesity rates have risen at an alarming rate in children, and this has likely contributed to an increased prevalence of SDB in children. Like the 'chicken and the egg' hypothesis, the temporal relationship of obesity and SDB is unclear but it is speculated that these two conditions converge to promote a fundamental disruption to normal lipid homeostasis. In this review, the effect of sleep disruption and SDB on lipid homeostasis in both murine and human models will be critically examined, with the intent of demonstrating that disrupted sleep in children is itself a precursor to obesity via disordered lipid homeostasis.

Reliability of home-based physiological sleep measurements in snoring and non-snoring 3-year olds

PURPOSE

To study snoring and non-snoring 3-year olds in their own homes and to establish reference values and night-to-night variability of physiological measurements taken during sleep.

METHODS

One hundred and sixty-six children, aged 3.2-4.0 years, identified as at high (n = 83, M/F = 1.5:1) or low (n = 83, M/F = 1.4:1) risk for persistent snoring, as rated by a parent, wore a sleep screening system (Grey Flash) for up to five consecutive nights, to measure snoring, oxygen saturation, heart rate, movement, sleep efficiency, and sleep timing.

RESULTS

The snoring group snored 25% of their total sleep time, while the non-snoring group snored just 7.6%. Reliability estimates were calculated, using intraclass correlations to establish the reliability of single recordings and the Spearman-Brown prophecy formula to estimate reliability over multiple recordings. Snoring (percent), turn index (number of turns per hour), and mean heart rate were adequately assessed in both groups with one recording night (all intraclass correlation coefficients (ICCs) ≥0.70). Furthermore, mean SpO(2) was measured with sufficient reliability with two recordings in non-snorers (ICC = 0.71), while five recording nights were necessary to reach reliability in snorers (ICC = 0.71). SpO(2) nadir did not reach adequate reliability in either group even after seven recording nights.

CONCLUSIONS

Our results showed that snoring can be measured reliably at home with just one recording night, whereas most other physiological sleep measures require two or more recordings.

Normative longitudinal maternal sleep: the first 4 postpartum months

OBJECTIVE

To describe the normative course of maternal sleep during the first 4 months postpartum.

STUDY DESIGN

Sleep was objectively measured using continuous wrist actigraphy. This was a longitudinal, field-based assessment of nocturnal sleep during postpartum weeks 2 through 16. Fifty mothers participated during postpartum weeks 2 through 13; 24 participated during postpartum weeks 9 through 16.

RESULTS

Maternal nocturnal sleep time was 7.2 (SD ± 0.95) hours and did not change significantly across postpartum weeks 2 through 16. Maternal sleep efficiency did improve across weeks 2 (79.7%; SD ± 5.5) through 16 (90.2%; SD ± 3.5) as a function of decreased sleep fragmentation across weeks 2 (21.7; SD ± 5.2) through 16 (12.8; SD ± 3.3).

CONCLUSION

Though postpartum mothers' total sleep time was higher than expected during the initial postpartum months, this sleep was highly fragmented (similar to fragmenting sleep disorders) and inefficient. This profile of disturbed sleep should be considered in intervention designs and family leave policies.

Invalidity of one actigraphy brand for identifying sleep and wake among infants

STUDY OBJECTIVES

Few commercially available brands of actigraphs (ACT) have been subjected to rigorous validation with infant participants. The purpose of this study was to examine the agreement between concurrent polysomnography (PSG) and one brand of ACT (AW-64, Mitter Co. Inc.) using appropriate statistical techniques among a sample of healthy infants.

METHODS

Twenty-two healthy infants (14.1+/-0.6 months) had one night of ankle ACT recording during research PSG at Kosair Children's Hospital Sleep Research Center in Louisville, Kentucky. Macroanalyses were conducted using the Bland-Altman concordance technique to assess agreement between total sleep time (TST) and wake after sleep onset (WASO) simultaneously measured by PSG and ACT, using two ACT algorithm settings. Microanalyses were also calculated to examine sensitivity, specificity, and accuracy of ACT within each PSG-identified sleep state. Correlations were calculated between PSG-identified arousals and the discrepancies between ACT and PSG.

RESULTS

The Bland-Altman concordance technique revealed that ACT underestimated TST by 72.25 (SD=61.48) minutes and by > or = 60 min among 54.55% of infants. Furthermore, ACT overestimated WASO by 13.85 (SD=30.94) minutes and by > or = 30 min among 40.91% of infants. Sensitivity, specificity, and accuracy analyses revealed that ACT adequately identified sleep, but poorly identified wake. PSG and ACT discrepancies were positively associated with PSG-identified arousals (r=.45).

CONCLUSIONS

Improved device and/or software development is needed before the AW-64 can be considered a valid method for identifying infant sleep and wake.