Developmental course of nighttime sleep-wake patterns in full-term and premature infants during the first year of life. I

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.

A systematic review of chronobiology for neonatal care units: What we know and what we should consider

A Cochrane 2016 review indicated cycled light might benefit neonatal health in hospital. We systematically reviewed chronobiological factors for neonatal health in hospital units, identifying 56 relevant studies on light-dark cycles, feeding, noise, massage therapy, rooming-in, incubators vs. cribs, neonatal units vs. homes, and time-of-day of birth. Empirical evidence for benefits from chronobiology is weaker than expected, including light. Mechanisms of clinical benefits are unclear (e.g., changes to sleep/activity vs. other circadian-regulated processes). Regarding light, studies concerning sleep and circadian-related outcomes predominate; yet, neonatologists may be more interested in weight gain and time spent in hospital. Generalisability of findings is limited as most studies targeted neonates in stable condition and without congenital anomalies. Further research is needed, in particular concerning potential circadian entraining signals such as timing of meals or medications. Longer-term outcomes (regarding e.g., neurodevelopment and infection), and who may be at risk from time-of-day of birth effects and why remain to be explored. Overall, there is promise and ample scope for research into how chronobiological factors affect health in hospitalised neonates.

A preliminary study on the performance of the Nanit auto-videosomnography scoring system against observed video scoring and actigraphy to estimate sleep-wake states in infants

GOAL AND AIMS

To examine the performance of the Nanit auto-videosomnography scoring system as a measure of sleep-wake states in infants compared to observed video scoring and actigraphy.

FOCUS TECHNOLOGY

Nanit's auto-videosomnography scoring system.

REFERENCE

Observed video scoring and actigraphy.

SAMPLE

Sixteen U.S. infants (age: 4-8 months).

DESIGN

Infants' sleep was assessed with the Nanit camera and actigraphy (micromotion logger sleep watch). Fifty nights were included in the analyses. Nanit's videos were processed via a computer vision algorithm and were scored by trained observers. Actigraphic data were scored with the validated Sadeh algorithm.

CORE ANALYTICS

Bland-Altman plots and epoch-by-epoch analyses (sensitivity, specificity, and total accuracy).

ADDITIONAL ANALYTICS

Specificity values for each night separately.

CORE OUTCOMES

Nanit estimates of sleep minute were not significantly different from observed sleep minute, but Nanit overestimated sleep minute relative to actigraphy by 17 minutes. Nanit overestimated wake minutes (wake after sleep onset by 5.3 minutes relative to observed scoring and underestimated wake after sleep onset by 19.1 minutes relative to actigraphy. The epoch-by-epoch analyses revealed that Nanit reached 97.8% sensitivity in classifying sleep and 60.4% specificity in classifying wake compared to observed scoring. The rates compared to actigraphy were 99.3% for sensitivity and 51.7% for specificity.

IMPORTANT ADDITIONAL OUTCOMES

Specificity values were lower for infants with lower wake after sleep onset.

CORE CONCLUSION

This preliminary study suggests that Nanit is highly accurate in detecting infant sleep compared to observed scoring and actigraphy. Specificity values are within the range of those reported previously for actigraphy devices that are commonly used in pediatric sleep research.

Sleep from Infancy Through Adolescence

This article describes the changes in normal sleep regulation, structure, and organization and sleep-related changes in respiration from infancy to adolescence. The first 2 years of age are striking, with more time asleep than awake. With development, the electroencephalogram architecture has a marked reduction in rapid eye movement sleep and the acquisition of K-complexes, sleep spindles, and slow-wave sleep. During adolescence there is a reduction in slow-wave sleep and a delay in the circadian phase. Infants have a more collapsible upper airway and lower lung volumes than older children, which predisposes them to obstructive sleep apnea and sleep-related hypoxemia.

Circadian rhythms as modulators of brain health during development and throughout aging

The circadian clock plays a prominent role in neurons during development and throughout aging. This review covers topics pertinent to the role of 24-h rhythms in neuronal development and function, and their tendency to decline with aging. Pharmacological or behavioral modification that augment the function of our internal clock may be central to decline of cognitive disease and to future chronotherapy for aging-related diseases of the central nervous system.

Development of the circadian system in early life: maternal and environmental factors

In humans, an adaptable internal biological system generates circadian rhythms that maintain synchronicity of behavior and physiology with the changing demands of the 24-h environment. Development of the circadian system begins in utero and continues throughout the first few years of life. Maturation of the clock can be measured through sleep/wake patterns and hormone secretion. Circadian rhythms, by definition, can persist in the absence of environmental input; however, their ability to adjust to external time cues is vital for adaptation and entrainment to the environment. The significance of these external factors that influence the emergence of a stable circadian clock in the first years of life remain poorly understood. Infants raised in our post-modern world face adverse external circadian signals, such as artificial light and mistimed hormonal cues via breast milk, which may increase interference with the physiological mechanisms that promote circadian synchronization. This review describes the very early developmental stages of the clock and common circadian misalignment scenarios that make the developing circadian system more susceptible to conflicting time cues and temporal disorder between the maternal, fetal, infant, and peripheral clocks.

Precision caffeine therapy for apnea of prematurity and circadian rhythms: New possibilities open up

Caffeine is the globally consumed psychoactive substance and the drug of choice for the treatment of apnea of prematurity (AOP), but its therapeutic effects are highly variable among preterm infants. Many of the molecular underpinnings of the marked individual response have remained elusive yet. Interestingly, the significant association between Clock gene polymorphisms and the response to caffeine therapy offers an opportunity to advance our understanding of potential mechanistic pathways. In this review, we delineate the functions and mechanisms of human circadian rhythms. An up-to-date advance of the formation and ontogeny of human circadian rhythms during the perinatal period are concisely discussed. Specially, we summarize and discuss the characteristics of circadian rhythms in preterm infants. Second, we discuss the role of caffeine consumption on the circadian rhythms in animal models and human, especially in neonates and preterm infants. Finally, we postulate how circadian-based therapeutic initiatives could open new possibilities to promote precision caffeine therapy for the AOP management in preterm infants.

Season is related to the slow wave and sigma activity of infants and toddlers

OBJECTIVE/BACKGROUND

Slow wave activity (SWA) and sigma frequency activity (SFA) are hallmarks of NREM sleep EEG and important indicators of neural plasticity, development of the central nervous system, and cognition. However, little is known about the factors that modulate these sleep EEG activities, especially in small children.

PATIENTS/METHODS

We analyzed the power spectral densities of SWA (1-4 Hz) and SFA range (10-15 Hz) from six EEG derivations of 56 infants (8 months) and 60 toddlers (24 months) during their all-night sleep and during the first and the last half of night sleep. The spectral values were compared between the four seasons.

RESULTS

In the spring group of infants, compared with the darker seasons, SFA was lower in the centro-occipital EEG derivations during both halves of the night. The SWA findings of the infants were restricted to the last half of the night (SWA2) and frontally, where SWA2 was higher during winter than spring. The toddlers presented less frontal SWA2 during winter compared with autumn. Both age groups showed a reduction in both SWA and SFA towards the last half of the night.

CONCLUSIONS

The sleep EEG spectral power densities are more often associated with seasons in infants' SFA range. The results might stem from seasonally changing light exposure, but the exact mechanism warrants further study. Moreover, contrary to the adult-like increment of SFA, the SFA at both ages was lower at the last part of the night sleep. This suggests different regulation of spindle activity in infants and toddlers.

Association of fetal eye movement density with sleeping and developmental problems in 1.5-year-old infants

Eye movement density (EMD) is an evaluation index of rapid eye movements observed during sleep. This study aimed to investigate the association of fetal EMD with sleeping and developmental problems in infancy. We observed 60 normal singleton pregnancies (gestational age 28-37 weeks) using ultrasonography for 1 h. Fetal eye movements were counted, and EMD was calculated. Participants answered questionnaires regarding their child's sleep and development 1.5 years after their delivery. The outcomes of an infant's sleep were night awakening (yes or no), bedtime (before or after 22:00), and nighttime sleep duration (< 9 or ≥ 9 h). An infant's development was evaluated using the Child Behavior Checklist (CBCL) T-score. We found that decreased fetal EMD was associated with increased night awakening at the age of 1.5 years (odds ratio 0.84, 95% confidence interval 0.69-1.00 per unit decrease in EMD). However, fetal EMD was not associated with bedtime or nighttime sleep duration. In addition, fetal EMD was independently associated with the total problems T-score of the CBCL at the age of 1.5 years in the multivariate model (p = 0.047). In conclusion, fetal EMD may be associated with sleep and developmental problems in infants.

A behavioral approach to annotating sleep in infants: Building on the classic framework

In infants, monitoring and assessment of sleep can offer valuable insights into sleep problems and neuro-cognitive development. The gold standard for sleep measurements is polysomnography (PSG), but this is rather obtrusive, and unpractical in non-laboratory situations. Behavioral observations constitute a non-obtrusive, infant-friendly alternative. In the current methodological paper, we describe and validate a behavior-based framework for annotating infant sleep states. For development of the framework, we used existing sleep data from an in-home study with an unobtrusive test setup. Participants were 20 infants with a mean age of 180 days. Framework development was based on Prechtl's method. We added rules and guidelines based on discussions and consent among annotators. Key to using our framework is combining data from several modalities, for example, closely observing the frequency, type, and quality of movements, breaths, and sounds an infant makes, while taking the context into account. For a first validation of the framework, we set up a small study with 14 infants (mean age 171 days), in which they took their day-time nap in a laboratory setting. They were continuously monitored by means of PSG, as well as by the test setup from the in-home study. Recordings were annotated based both on PSG and our framework, and then compared. Data showed that for scoring wake vs. active sleep vs. quiet sleep the framework yields results comparable to PSG with a Cohen's Kappa agreement of ≥0.74. Future work with a larger cohort is necessary for further validating this framework, and with clinical populations for determining whether it can be generalized to these populations as well.

Preventing postpartum insomnia by targeting maternal versus infant sleep: a protocol for a randomized controlled trial (the Study for Mother-Infant Sleep “SMILE”)

Symptoms of insomnia are common during the perinatal periods and are linked to adverse parent/infant outcomes. Theories on insomnia development (e.g. 3P model) suggest that significant sleep disruption (e.g. nighttime infant care) can precipitate, while unhelpful sleep-related cognitions/behaviors can perpetuate parental insomnia symptoms. This study aims to examine how two interventions, one addressing infant sleep as the precipitator, the other targeting maternal sleep-related cognitions/behaviors as the perpetuator, might prevent postpartum insomnia. Participants are 114 nulliparous females 26 to 32 weeks gestation, with self-reported insomnia symptoms (Insomnia Severity Index scores ≥ 8). Participants are randomized to one of three conditions and receive: (1) a “responsive bassinet” used until 6 months postpartum, designed to boost/consolidate infant sleep and target infant sleep as a precipitator of insomnia, (2) therapist-assisted cognitive behavioral therapy for insomnia, addressing unhelpful sleep-related cognitions/behaviors as perpetuators of insomnia, or (3) a sleep hygiene booklet (control condition). The primary outcome is maternal insomnia symptoms. Secondary outcomes include maternal sleep duration/quality, mental health (e.g. depression, anxiety), and wellbeing-related variables (e.g. sleep-related impairment). Outcomes are assessed using validated instruments at 26–32 and 35–36 weeks’ gestation, and 2, 6, and 12 months postpartum. This study adopts an early-intervention approach and longitudinally compares two distinct approaches to prevent postpartum insomnia in an at-risk population. If interventions are efficacious, findings will demonstrate how interventions targeting different mechanisms mitigate insomnia symptoms in perinatal populations. This will provide empirical evidence for future development of multi-component sleep intervention to improve mother-infant wellbeing.

Clinical Trial Registration: The Study for Mother-Infant Sleep (The SMILE Project): reducing postpartum insomnia using an infant sleep intervention and a maternal sleep intervention in first-time mothers. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=377927, Australian New Zealand Clinical Trials Registry: ACTRN12619001166167.

Sleep Measurement in Children-Are We on the Right Track?

Sleep plays a critical role in the development of healthy children. Detecting sleep and sleep disorders and the effectiveness of interventions for improving sleep in children require valid sleep measures. Assessment of sleep in children, in particular infants and young children, can be a quite challenging task. Many subjective and objective methods are available to evaluate various aspects of sleep in childhood, each with their strengths and limitations. None can, however, replace the importance of thorough clinical interview with detailed history and clinical examination by a sleep specialist.

Apnoea of Prematurity and Neurodevelopmental Outcomes: Current Understanding and Future Prospects for Research

Infants who are born prematurely are at significant risk of apnoea. In addition to the short-term consequences such as hypoxia, apnoea of prematurity has been associated with long-term morbidity, including poor neurodevelopmental outcomes. Clinical trials have illustrated the importance of methylxanthine drugs, in particular caffeine, in reducing the risk of long term adverse neurodevelopmental outcomes. However, the extent to which apnoea is causative of this secondary neurodevelopmental delay or is just associated in a background of other sequelae of prematurity remains unclear. In this review, we first discuss the pathophysiology of apnoea of prematurity, previous studies investigating the relationship between apnoea and neurodevelopmental delay, and treatment of apnoea with caffeine therapy. We propose a need for better methods of measuring apnoea, along with improved understanding of the neonatal brain's response to consequent hypoxia. Only then can we start to disentangle the effects of apnoea on neurodevelopment in preterm infants. Moreover, by better identifying those infants who are at risk of apnoea, and neurodevelopmental delay, we can work toward a risk stratification system for these infants that is clinically actionable, for example, with doses of caffeine tailored to the individual. Optimising treatment of apnoea for individual infants will improve neonatal care and long-term outcomes for this population.

Development of the circadian system and relevance of periodic signals for neonatal development

Circadian rhythms are generated endogenously with a period of approximately 24h. Studies carried out during the last decade indicate that the circadian system develops before birth, and that the suprachiasmatic nucleus, a structure that is considered the mammalian circadian clock, is present in primates from the middle of pregnancy. Recent evidence shows that the infants' circadian system is sensitive to light from very early stages of development; it has also been proposed that low-intensity lighting can regulate the developing clock. After birth there is a progressive maturation of the outputs of the circadian system with marked rhythms in sleep-wake phenomena and hormone secretion. These facts express the importance of circadian photic regulation in infants. Thus, the exposure of premature babies to light/dark cycles results in a rapid establishment of activity/rest patterns, which are in the light-dark cycle. With the continuous study of the development of the circadian system and the influence on human physiology and disease, it is anticipated that the application of circadian biology will become an increasingly important component in the perinatal care.

Sleep-wake regulation in preterm and term infants

Study Objectives

In adults, wakefulness can be markedly prolonged at the expense of sleep, e.g. to stay vigilant in the presence of a stressor. These extra-long wake bouts result in a heavy-tailed distribution (highly right-skewed) of wake but not sleep durations. In infants, the relative importance of wakefulness and sleep are reversed, as sleep is necessary for brain maturation. Here, we tested whether these developmental pressures are associated with the unique regulation of sleep–wake states.

Methods

In 175 infants of 28–40 weeks postmenstrual age (PMA), we monitored sleep–wake states using electroencephalography and behavior. We constructed survival models of sleep–wake bout durations and the effect of PMA and other factors, including stress (salivary cortisol), and examined whether sleep is resilient to nociceptive perturbations (a clinically necessary heel lance).

Results

Wake durations followed a heavy-tailed distribution as in adults and lengthened with PMA and stress. However, differently from adults, active sleep durations also had a heavy-tailed distribution, and with PMA, these shortened and became vulnerable to nociception-associated awakenings.

Conclusions

Sleep bouts are differently regulated in infants, with especially long active sleep durations that could consolidate this state’s maturational functions. Curtailment of sleep by stress and nociception may be disadvantageous, especially for preterm infants given the limited value of wakefulness at this age. This could be addressed by environmental interventions in the future.

Researcher Choices for Infant Sleep Assessment: Parent Report, Actigraphy, and a Novel Video System

Incorporating infant sleep, either as a predictor or as an outcome variable, into interdisciplinary work has become increasingly popular. Sleep researchers face many methodological choices that have implications for the reliability and validity of the data. Here, the authors directly investigated the impact of design and measurement choices in a small, longitudinal sample of infants. Three sleep measurement techniques-parent-reported sleep diaries, actigraphy (Micromini Sleep Watch), and a commercial videosomnography (Nanit)-were included, using actigraphy as the baseline. Nine infants' sleep (4 girls) was measured longitudinally using all three measurement techniques. Nanit provided summary statistics, using a proprietary algorithm, for nightly sleep parameters. The actigraphy data were analyzed with both the Sadeh Infant and Sadeh algorithms. The extent to which measurements converged on sleep start and end time, number of wake episodes, sleep efficiency, and sleep duration was assessed. Measures were positively correlated. Difference scores revealed similar patterns of greater sleep estimation in parent reports and Nanit compared with actigraphy. Bland-Altman plots revealed that much of the data were within the limits of agreement, tentatively suggesting that Nanit and actigraphy may be used interchangeably. Graphs display significant variability within and between individual infants as well as across measurement techniques. Potential confounding variables that may explain the discrepancies between parent report, Sadeh Infant, Sadeh, and Nanit are discussed. The findings are also used to speak to the advantages and disadvantages of design and measurement choices. Future directions focus on the unique contributions of each measurement technique and how to capitalize on them.

The relation between sleep and neurocognitive development in infancy and early childhood: A neuroscience perspective

Sleep is essential for human life. It has different characteristics in the early stages of life compared to later periods: during development, qualitative and quantitative changes in sleep features occur such as the onset of REM/NREM sleep at 3 months, the progressive increase of night sleep duration, and the reduction of total sleep time. Sleep seems to be essential in the cognitive functions' development, especially in the first period of life. Indeed, higher rates of night sleep at the age of 12 and 18 months are associated with higher executive functions' performance. Furthermore, memory consolidation occurs during sleep and sleep contributes to children's learning not only in retaining information but also in organizing memories most efficiently. Therefore, sleep problems could cause negative effects on some features of cognitive development like memory, executive functions, and learning process. There is also an intimate relationship between sleep and regulation of emotional brain functions, with a link between sleep disturbance and behavioral problems.

Infant Sleep Difficulties at the 6th Week and the 12th Month Postpartum: What Is their Relationship with Maternal Mental Health and Other Perinatal Factors?

INTRODUCTION

Infant sleep difficulties are often a challenge for new parents and may be related to maternal mood.

AIM

The aim of this study was to investigate whether the presence of reported infant sleep difficulties at the 6th week and at the 12th month postpartum is associated with maternal psychological well-being and the presence of a mental health disorder in the perinatal period or with other perinatal factors.

METHODS

It is a retrospective longitudinal study, examining a sample of 622 women who attended a 12-month innovative psychosocial intervention. Data were obtained through the EPDS and PHQ-9 psychometric tools, and the completion of a health history. Statistical analyses included Spearman rank correlation coefficients and Chi-square tests.

RESULTS

Reported infant sleep difficulties at the 6th week postpartum were associated with a) increased maternal scores on psychometric tools (EPDS and PHQ-9) during pregnancy and at the 6th week postpartum, b) the presence of pathological maternal mental health symptoms in the perinatal period (p =.034), c) high maternal educational level (p <.001), and d) reported maternal breastfeeding difficulties at the 6th week postpartum (p =.031). Reported infant sleep difficulties at the 12th month postpartum were associated with a) increased maternal scores on the EPDS at the 6th week after birth (p =.030), and at the 6th (p =.031) and the 12th month (p =.006) postpartum, b) reported infant sleep difficulties (p <.001) and frequent infant awakenings in the puperperium (p <.001), d) maternal fatigue at the 6th week postpartum (p <.001), e) infant gastro-esophageal reflux problems (p <.001), and f) high maternal educational level (p =.001).

CONCLUSIONS

This study demonstrates a positive relationship between infant sleep difficulties at the 6th week and at the 12th months postpartum, with poor maternal mental health in the perinatal period.

Non-contact Sleep/Wake Monitoring Using Impulse-Radio Ultrawideband Radar in Neonates

Background: The gold standard for sleep monitoring, polysomnography (PSG), is too obtrusive and limited for practical use with tiny infants or in neonatal intensive care unit (NICU) settings. The ability of impulse-radio ultrawideband (IR-UWB) radar, a non-contact sensing technology, to assess vital signs and fine movement asymmetry in neonates was recently demonstrated. The purpose of this study was to investigate the possibility of quantitatively distinguishing and measuring sleep/wake states in neonates using IR-UWB radar and to compare its accuracy with behavioral observation-based sleep/wake analyses using video recordings. Methods: One preterm and three term neonates in the NICU were enrolled, and voluntary movements and vital signs were measured by radar at ages ranging from 2 to 27 days. Data from a video camcorder, amplitude-integrated electroencephalography (aEEG), and actigraphy were simultaneously recorded for reference. Radar signals were processed using a sleep/wake decision algorithm integrated with breathing signals and movement features. Results: The average recording time for the analysis was 13.0 (7.0-20.5) h across neonates. Compared with video analyses, the sleep/wake decision algorithm for neonates correctly classified 72.2% of sleep epochs and 80.6% of wake epochs and achieved a final Cohen's kappa coefficient of 0.49 (0.41-0.59) and an overall accuracy of 75.2%. Conclusions: IR-UWB radar can provide considerable accuracy regarding sleep/wake decisions in neonates, and although current performance is not yet sufficient, this study demonstrated the feasibility of its possible use in the NICU for the first time. This unobtrusive, non-contact radar technology is a promising method for monitoring sleep/wake states with vital signs in neonates.

Longitudinal study of sleep behavior and motor development in low-birth-weight preterm children from infancy to preschool years

OBJECTIVE

To verify the relationship between sleep characteristics and motor development in low-birth-weight preterm infants during infancy and preschool years.

METHOD

Forty-one healthy preterm infants (<37 weeks' gestation) with low birth weight (≤1500 g) were assessed longitudinally at three different time points: at 6 months of corrected age, at 12 months of corrected age, and at 4-5 years of chronological age. At 6 and 12 months, motor development was assessed using the Denver Developmental Screening Test II and Alberta Infant Motor Scale, while sleep-related habits and disturbances were assessed using the Brief Infant Sleep Questionnaire. At 4-5 years, motor development was reassessed using the Pediatric Evaluation of Disability Inventory and sleep was reassessed using the Sleep Disturbance Scale for Children. Correlations were performed using sleep quality as the predictor variable and motor development as the outcome variable.

RESULTS

Most infants had suspected delay/atypical development at 6 and 12 months, with no difference between the scales (p = 1.000). Suspected delay/atypical development were associated with lateral sleep position (p = 0.004), greater number of nighttime awakenings (p = 0.008), and longer awake periods (p = 0.014) only at 6 months. At 4-5 years, the suspected delay/atypical development observed at 6 and 12 months disappeared.

CONCLUSIONS

Sleep quality correlated with delayed/atypical motor development in healthy preterm infants with low birth weight only at 6 months of corrected age, which did not appear to affect later development of motor skills.

Newly walking infants' night sleep impacts next day learning and problem solving

Sleep is part of the process that prepares children and adults for next day cognitive activity. Insufficient or fragmented sleep has a detrimental impact on subsequent encoding (Rouleau et al., 2002) and cognitive functioning (Joo et al., 2012). However, fragmented sleep early in life is a developmental norm, limiting the extent to which conclusions derived from older populations can be generalized. To directly test the continuity of this relationship, newly-walking infants' (N=58) sleep was monitored overnight using actigraphy. The next morning they were taught a motor problem-solving task. The task required infants to navigate through a tunnel to reach a goal at the other end. We coded infants' exploratory behaviors and the extent of training required to solve the task. Using a cluster analysis that accounted for exploratory behaviors and number of training prompts, infants were sorted into three profiles: those who found the task Easy to solve, those who found it Difficult, and those who Never solved it. Wake episodes and sleep efficiency were entered as predictors of cluster membership in a multinomial logistic regression. Of the infants who ultimately solved the task, those with more wake episodes and lower sleep efficiency had more difficulty. Specifically, fragmentation appeared to negatively impact preparedness to learn. Contrary to our expectations, infants who Never solved the task had the least fragmented sleep, indicating that an optimal level of fragmentation is needed for efficient problem-solving. For infants, some level of sleep fragmentation is needed the night before learning in order to solve a task efficiently. These findings highlight the interaction between developmental domains, from sleep quality to motor experience, and their impact on infant learning in real time.

Which are the Central Aspects of Infant Sleep? The Dynamics of Sleep Composites across Infancy

Sleep during infancy is important for the well-being of both infant and parent. Therefore, there is large interest in characterizing infant sleep with reliable tools, for example by combining actigraphy with 24-h-diaries. However, it is critical to select the right variables to characterize sleep. In a longitudinal investigation, we collected sleep data of 152 infants at ages 3, 6, and 12 months. Using principal component analysis, we identified five underlying sleep composites from 48 commonly-used sleep variables: Sleep Night, Sleep Day, Sleep Activity, Sleep Timing, and Sleep Variability. These composites accurately reflect known sleep dynamics throughout infancy as Sleep Day (representing naps), Sleep Activity (representing sleep efficiency and consolidation), and Sleep Variability (representing day-to-day stability) decrease across infancy, while Sleep Night (representing nighttime sleep) slightly increases, and Sleep Timing becomes earlier as one ages. We uncover interesting dynamics between the sleep composites and demonstrate that infant sleep is not only highly variable between infants but also dynamic within infants across time. Interestingly, Sleep Day is associated with behavioral development and therefore a potential marker for maturation. We recommend either the use of sleep composites or the core representative variables within each sleep composite for more reliable research.

Promoting Independent Sleep Onset in Young Children: Examination of the Excuse Me Drill

Background: There is compelling evidence to support behavioral interventions as the first-line approach for bedtime resistance in young children. Among the behavioral treatment options, extinction ("cry it out") has the most extensive empirical support and tends to produce the most rapid gains. There are well known problems with the use of extinction, however, including side effects (extinction burst, spontaneous recovery) and poor acceptance, not to mention that extinction fails to teach children appropriate replacement behaviors (what "to do"). This study introduces a new behavioral sleep intervention, the Excuse Me Drill, designed to address some of the limitations of extinction. The EMD was formally evaluated for the first time using a multiple-baseline research design across four participants with sleep disturbance.Participants: Participants included four children who were clinically referred to outpatient pediatric psychology clinics for the treatment of behavioral insomnia of childhood, and included one 2-year-old female, two 7-year-old females, and one 7-year-old male. All participants had a history of dependent sleep onset at bedtime (i.e., parents remained in the child's bedroom upon sleep onset). Methods: A non-concurrent multiple baseline design across participants was used to experimentally evaluate the effectiveness of the EMD. During baseline, parents collected data on independent sleep onset and disruptive bedtime behaviors, but conducted the bedtime routine as usual. Immediately following baseline, parents implemented the EMD protocol until data indicated that children were consistently initiating sleep independently. Follow-up data were collected to determine the extent to which children continued to initiate sleep independently at bedtime in absence of the EMD. Results: Outcomes were promising as the EMD successfully taught all four children to initiate sleep independently and produced notable decreases in disruptive bedtime behavior. Results were maintained at follow-up for three of four participants. In addition, parents rated the EMD to be a socially acceptable procedure for their children. Conclusions: Results of this study indicate that the EMD was effective in promoting independent sleep onset and reducing disruptive bedtime behavior that maintained over time. The EMD should be considered to be a viable alternative to traditional extinction procedures for pediatric sleep disturbance. Implications for practice, limitations, and direction for future research are discussed.

Time for bed! Earlier sleep onset is associated with longer nighttime sleep duration during infancy

OBJECTIVE/BACKGROUND

Clinical recommendations include putting infants to bed using a consistent bedtime routine at an appropriate hour to promote longer nighttime sleep. Actigraphy was used in this exploratory study to examine how bedtime routines and nighttime sleep onset were associated with nighttime total sleep time (TST) and efficiency from 6 to 24 weeks of age.

PATIENTS/METHODS

Infants (n = 24) wore sleep actigraphs for three, one-week periods at 6, 15, and 24 weeks of age. Nighttime TST, sleep efficiency, sleep onset and offset were quantified. Mothers reported on infant bedtime routines using the Brief Infant Sleep Questionnaire at each age. Multilevel models examined between- and within-person associations.

RESULTS

As infants aged, sleep onset was earlier, and bedtime routines became shorter (p's < 0.05). Infants fell asleep between 7 and 8:00PM on 24% of the nights. Most mothers (70%) reported that they often fed infants to sleep for the night. For every 1 h earlier in infants' usual sleep onset, nighttime TST was 34.4 min longer that night (p < 0.01). Infants with earlier than usual sleep onset had slightly earlier sleep offset the next morning (8.4 min for every 1 h earlier in onset; p = 0.02). Between-person analyses showed similar patterns. Infants with a more consistent bedtime routine and who were not typically fed to sleep at bedtime had longer nighttime TST at 6 weeks, with a trend or no association at later ages.

CONCLUSION

Infants who fell asleep earlier also slept longer at night. Keeping infants up later in hopes of them sleeping in longer may be counterproductive.

Long-range temporal organisation of limb movement kinematics in human neonates

OBJECTIVE

Movement provides crucial sensorimotor information to the developing brain, evoking somatotopic cortical EEG activity. Indeed, temporal-spatial organisation of these movements, including a diverse repertoire of accelerations and limb combinations (e.g. unilateral progressing to bilateral), predicts positive sensorimotor outcomes. However, in current clinical practice, movements in human neonates are qualitatively characterised only during brief periods (a few minutes) of wakefulness, meaning that the vast majority of sensorimotor experience remains unsampled. Here our objective was to quantitatively characterise the long-range temporal organisation of the full repertoire of newborn movements, over multi-hour recordings.

METHODS

We monitored motor activity across 2-4 h in 11 healthy newborn infants (median 1 day old), who wore limb sensors containing synchronised tri-axial accelerometers and gyroscopes. Movements were identified using acceleration and angular velocity, and their organisation across the recording was characterised using cluster analysis and spectral estimation.

RESULTS

Movement occurrence was periodic, with a 1-hour cycle. Peaks in movement occurrence were associated with higher acceleration, and a higher proportion of movements being bilateral.

CONCLUSIONS

Neonatal movement occurrence is cyclical, with periods consistent with sleep-wake behavioural architecture. Movement kinematics are organised by these fluctuations in movement occurrence. Recordings that exceed 1-hour are necessary to capture the long-range temporal organisation of the full repertoire of newborn limb movements.

SIGNIFICANCE

Future work should investigate the prognostic value of combining these movement recordings with synchronised EEG, in at-risk infants.

Mothers' Attachment Style as a Predictor of Breastfeeding and Room-Sharing Practices

OBJECTIVE

To prospectively assess breastfeeding and room-sharing practices during the infant's first 6 months and investigate whether mothers' own adult attachment style predicts the initiation and course of these recommended parenting behaviors.

METHOD

This study included 193 mother-infant dyads living in the Netherlands. Diary methodology was used to generate 27 weekly measures of breastfeeding and room-sharing during the infant's first 6 months. Multilevel mixed effects models were used to examine trajectories of breastfeeding and room-sharing and to test whether mothers' own adult attachment style predicted the initiation and course of these behaviors, adjusting for covariates.

RESULTS

Most (86%) mothers initiated breastfeeding immediately after birth and the rates of breastfeeding declined steadily over the 6 months (b = -2.47, SE = 0.19, p < .001). Mothers with higher attachment avoidance showed faster decreases in breastfeeding than less avoidant mothers (b = -1.07, SE = 0.21, p < .001). Sixty-four percent of mothers engaged in room-sharing after birth which also decreased steadily over the 6 months (b = -3.51, SE = 0.21, p < .001). Mothers' attachment style did not predict the initiation or course of room-sharing.

CONCLUSIONS

Given the major implications of breastfeeding and room-sharing for infants' health, safety, and development, the pediatrics community has issued clear guidelines encouraging these behaviors. Yet many new parents do not adhere to the recommended practices. This study identifies mothers' adult attachment style as a predictor of breastfeeding over time that could be incorporated into interventions for parents.

Sleep architecture is related to the season of PSG recording in 8-month-old infants

To date, little is known about the impact of season on infant sleep. In higher latitudes, the duration of daily light time varies substantially between different seasons, and environmental light is one potential factor affecting sleep. In this cohort study, one-night polysomnography (PSG) was performed on 72 healthy 8-month-old infants in 2012 and 2013 to study the effect of season on the sleep architecture of young infants in Finland. The children were divided into four subgroups, according to the amount of light during their birth season and the amount of light during the season of the PSG recordings, corresponding to spring, summer, autumn, and winter. We found that the season of birth did not have an impact on the infants' sleep architecture at 8 months of age, but the season of the PSG recording did have an effect on several sleep variables. In the PSGs conducted during the spring, there was less N3 sleep and more N2 sleep than in the PSGs conducted during the autumn. In addition, there was more fragmented sleep during spring than autumn. According to our data, the season has an effect on the sleep architecture of young infants and should, therefore, be considered when evaluating the PSG findings of young infants. The exact mechanisms behind this novel finding remain unclear, however. The findings imply that infants` sleep is affected by the season or light environment, as is the case in adult sleep. Since potential explanatory factors, such as direct natural or artificial light exposure and the melatonin levels of the infants, were not controlled, more research is needed in the future to better understand this phenomenon.

Sleep disordered breathing (SDB) in neonates and implications for its long-term impact

Sleep-disordered breathing (SDB) is a significant cause of morbidity in neonates and young infants. SDB occurs more commonly in preterm infants and in neonates with underlying syndromes. Recent evidence shows that infants with obstructive sleep apnoea (OSA) or SDB have greater health care resource utilization, including longer hospital stay. Management of SDB includes non-invasive ventilation or surgical interventions tailored to the patient. Screening high risk newborns should allow for early diagnosis and timely therapeutic intervention for this population. However, the thresholds for diagnosing SDB and for guiding and implementing treatment in neonates remain unclear. A collective effort is required to standardize the practice worldwide. This article will discuss neonatal sleep physiology and characteristics of neonatal sleep, with an emphasis on the epidemiology and diagnosis of SDB in neonates and its implications for long term outcomes.

Considering Sleep, Mood, and Stress in a Family Context: A Preliminary Study

Background: During the first years of life, parental sleep strongly depends on child’s sleep quality. Poor parental sleep may relate to increased stress and negative mood. However, there is a lack of sleep studies focusing on all family members. This study aimed to investigate the relationship between sleep, mood, and stress in mothers, fathers and children. Methods: Data were obtained from 65 parental couples and 65 children (2 to 36 months). Data on sleep for all family members and stress of parents were completed by both mothers and fathers through questionnaires and sleep diaries. Results: Toddlers’ positive mood before nocturnal sleep was significantly associated with reduced wake times after sleep onset. Mothers reported worse sleep quality compared to fathers. Shorter sleep onset latency in fathers and better sleep efficiency in mothers were linked with better self-reported mood upon awakening. In mothers, but not in fathers, poor sleep quality was associated with higher perceived stress. Conclusion: Results suggest bidirectional relationships between sleep and mood in children, mothers and fathers. Moreover, results evidence poorer sleep in mothers, compared to fathers, which was linked with increased parenting stress. This gender gap should be further considered in studies with larger samples and in clinical contexts.

Evaluating motion detection to score sleep disturbance for children: A translational approach to developing a measurement system

Information obtained via direct observation of children's sleep disturbance throughout the night in their home can guide the assessment and treatment process, but watching live or via recorded video might be impractical in terms of time expenditures. In Experiment 1, we assessed the accuracy and reliability of a motion-detection camera with human motor movements. In Experiment 2, we tested the system's generality by using it to obtain in-home measures of sleep disturbance for three children with autism spectrum disorder and compared the accuracy to a continuous measurement system. We also measured scoring efficiency and assessed parents' acceptability of the camera. Results provide preliminary support for motion detection in measuring sleep disturbance, but further evaluation of motion detection to improve accuracy is warranted.

Video Analysis of Parent-Child Interactions in Behavioral Sleep Disorders: Development of a Scoring Algorithm

Introduction: Behavioral sleep disorders, including chronic insomnia (CI), are generally assessed by subjective parent interview. However, evidence suggests that parental report of children's overnight behaviors is unreliable, perhaps due to recall bias or confusion due to sleep deprivation. Video technology has been used clinically to capture complex behavioral disorders in children during the day. However, there is no standardized means of analyzing child and parent behavior at bedtime or during the night. We aimed to create an algorithm for this purpose. Methods: Child brain tumor survivors (a population previously shown to have a high prevalence of CI) were screened for difficulties initiating and maintaining sleep using sub-scales from the Sleep Disturbance Scale for Children. Those who screened positive (n = 3) then completed a detailed parent interview to confirm a clinical diagnosis of CI. One night of home video footage was obtained from initial settling period to morning waking (SOMNOmedics camera). Footage was imported into BORIS^© software and a coding system for parent and child behavior was developed over multiple iterations until agreeable inter-rater reliability (>70%) was achieved between two independent coders. Results: The final coding categories were: 1) time domains, 2) physical environment, 3) child global status, 4) location, 5) activity, and 6) physical interaction. This achieved 74% inter-reliability in its last iteration. Discussion: A statistically acceptable behavior scoring algorithm was achieved. With further development, this tool could be applied clinically to investigate behavioral insomnia and in research to provide more objective outcome measurement.

Parent-Infant Room Sharing During the First Months of Life: Longitudinal Links With Behavior During Middle Childhood

Current recommendations encourage parent–infant room sharing for the first 6 months of life. This longitudinal study (N = 193) is the first to examine long‐term relations of early room sharing with three domains of child behavior: sleep, behavior problems, and prosocial behavior. Information on room sharing was collected daily for infants’ first 6 months. At ages 6, 7, and 8 years, outcomes were assessed with maternal and teacher questionnaires and behavioral observations. Early room sharing was not related to sleep problems or behavior problems. Additionally, more weeks of room sharing were positively related to higher maternal ratings of child sleep quality and more prosocial behavior. In conclusion, early room sharing appears to be related to positive, but not negative, behavior outcomes in middle childhood.

A Community-Based Study of Sleep and Cognitive Development in Infants and Toddlers

STUDY OBJECTIVES

To examine the prevalence and correlates of nighttime awakenings and to explore the association between sleep and cognitive development in a community sample of infants and toddlers.

METHODS

A total of 590 healthy infants (aged 2-11 months) and 512 toddlers (aged 12-30 months) from 8 provinces of China were assessed for their sleep and cognitive development. Data on sleep duration and nighttime awakenings were collected through the Brief Infant Sleep Questionnaire. Cognitive development was assessed by trained pediatricians using the Bayley Scales of Infant Development.

RESULTS

Prevalence of no nighttime awakening, and nighttime awakening(s) for 1×/night, 2×/night, and ≥ 3×/night was 6.8%, 20.2%, 33.2%, and 39.3% in infants, and was 25.8%, 34.6%, 23.8%, and 15.8% in toddlers, respectively. Nighttime awakenings were generally associated with younger age, lower maternal education level, and being currently breastfed. In addition, nighttime awakenings were associated with being boys in toddlers. After controlling for potential confounders, infants with nighttime awakenings for 2×/night were found to have significantly higher Mental Development Index (MDI) score, as compared to those without and those with more frequent nighttime awakenings. However, toddlers with nighttime awakenings for ≥ 3×/night had significantly lower MDI, as compared to those with fewer nighttime awakenings. Total sleep duration was not associated with any developmental indices in both infants and toddlers.

CONCLUSIONS

Frequent nighttime awakenings are associated with poor cognitive functions in toddlers. Meanwhile, a nonlinear association between nighttime awakenings and cognitive performance was found among infants. The findings provide a developmental context for the effect of sleep on cognitive abilities in young children. Further longitudinal studies and interventional studies on the effects of parent-based sleep-focused intervention on cognitive abilities among young children are warranted.

Pediatric Videosomnography: Can Signal/Video Processing Distinguish Sleep and Wake States?

The term videosomnography captures a range of video-based methods used to record and subsequently score sleep behaviors (most commonly sleep vs. wake states). Until recently, the time consuming nature of behavioral videosomnography coding has limited its clinical and research applications. However, with recent technological advancements, the use of auto-videosomnography techniques may be a practical and valuable extension of behavioral videosomnography coding. To test an auto-videosomnography system within a pediatric sample, we processed 30 videos of infant/toddler sleep using a series of signal/video-processing techniques. The resulting auto-videosomnography system provided minute-by-minute sleep vs. wake estimates, which were then compared to behaviorally coded videosomnography and actigraphy. Minute-by-minute estimates demonstrated moderate agreement across compared methods (auto-videosomnography with behavioral videosomnography, Cohen's kappa = 0.46; with actigraphy = 0.41). Additionally, auto-videosomnography agreements exhibited high sensitivity for sleep but only about half of the wake minutes were correctly identified. For sleep timing (sleep onset and morning rise time), behavioral videosomnography and auto-videosomnography demonstrated strong agreement. However, nighttime waking agreements were poor across both behavioral videosomnography and actigraphy comparisons. Overall, this study provides preliminary support for the use of an auto-videosomnography system to index sleep onset and morning rise time only, which may have potential telemedicine implications. With replication, auto-videosomnography may be useful for researchers and clinicians as a minimally invasive sleep timing assessment method.

Sleep Disturbances in Newborns

The purpose of this review is to serve as an introduction to understanding sleep in the fetus, the preterm neonate and the term neonate. Sleep appears to have numerous important roles, particularly in the consolidation of new information. The sleep cycle changes over time, neonates spend the most time in active sleep and have a progressive shortening of active sleep and lengthening of quiet sleep. Additionally, the sleep cycle is disrupted by many things including disease state and environment, and the amplitude integrated EEG can be a useful tool in evaluating sleep, and sleep disturbances, in neonates. Finally, there are protective factors for infant sleep that are still being studied.

Sleep Characteristics and Temperament in Preterm Children at Two Years of Age

STUDY OBJECTIVES

We aimed to compare 2-year-old children born preterm with children born full term regarding: (1) sleep characteristics, (2) temperament, and (3) relations between sleep pattern and habits and temperament.

METHODS

The study included 51 preterm children with normal cognitive, language, and motor development (mean = 20.94 months, standard deviation [SD] = 4.08) and 57 full-term children (mean = 21.19, SD = 4.32). To assess sleep-related difficulties and habits and child temperament, mothers completed the following questionnaires: the (1) Sleep Disturbance Scale for Children-adapted (SDSC); (2) Brief Infant Sleep Questionnaire (BISQ); and (3) Italian Temperament Questionnaires-version 12-36 months (QUIT).

RESULTS

Preterm children needed less support to fall asleep and fell asleep more often alone in their own bed compared to those born at full term; however, preterm children showed more frequent sleep difficulties, such as restlessness and breathing problems during the night. In addition, preterm children had lower scores in the temperamental dimension of attention and higher scores in negative emotionality than full-term children. Finally, sleep problems were correlated with higher motor activity, lower social orientation and attention, and increased negative emotionality; a shorter nocturnal sleep duration was related to higher motor activity and lower inhibition to novelty whereas an earlier rise time was associated with lower attention and social orientation.

CONCLUSIONS

Preterm children showed sleep pattern problems and disturbance, predominance of attention problems, and negative emotionality related to sleep disruption.

I. INTRODUCTION: UNDERSTANDING THE TRANSITION TO SIBLINGHOOD FROM A DEVELOPMENTAL PSYCHOPATHOLOGY AND ECOLOGICAL SYSTEMS PERSPECTIVE

The birth of an infant sibling is a common occurrence in the lives of many toddler and preschool children. Early childhood is also a time for the emergence of disruptive behavior problems that may set the stage for later problem behaviors. The current study examined individual differences in young children’s behavioral and emotional adjustment after the birth of a sibling in an effort to uncover developmental trajectories reflecting sudden and persistent change (maladaptation), adjustment and adaptation (resilience), gradual linear increases, and no change (stability and continuity). Growth mixture modeling (GMM) was conducted with a sample of 241 families expecting their second child using a longitudinal research design across the first year after the sibling’s birth (prenatal, 1, 4 8 and 12 months) on seven syndrome scales of the Child Behavior Checklist (CBCL 1.5–5:(Achenbach & Rescorla, 2000 ): aggression, attention problems, anxiety/depression, emotional reactivity, withdrawal, somatic complaints, and sleep problems. For all scales, multiple classes describing different trajectory patterns emerged that reflected predominantly intercept differences; children high on problem behavior after the birth were those high before the birth. There was no evidence of a sudden, persistent maladaptive response indicating children underwent a developmental crisis for any of the problem behaviors examined. Most children were low on all problem behaviors examined and showed little change or actually declined in problem behaviors over time, although some children did experience more pronounced changes in the borderline clinical or clinical range. Only in the case of aggressive behavior was there evidence of an Adjustment and Adaptation Response showing a sudden change (prenatal to 1 month) that subsided by 4 months, suggesting that some young children react to stressful life events but adapt quickly to these changing circumstances. Further, children’s withdrawal revealed a curvilinear, quadratic path, suggesting children both increased and decreased in their withdrawal over time. Guided by a developmental ecological systems framework, we employed data mining procedures to uncover the child, parent, and family variables that best discriminated the different trajectory classes and found that children’s temperament, coparenting, parental self-efficacy, and parent-child attachment relationships were prominent in predicting children’s adjustment after the birth of an infant sibling. Finally, when trajectory classes were used to predict sibling relationship quality at 12 months, children high on aggression, attention problems, and emotional reactivity in the year after the birth engaged in more conflict and less positive involvement with the infant sibling at the end of the first year.