Smiling in newborns during communicative wake and active sleep

Many studies have investigated infant smiling behaviour during wake and active sleep. In the majority of studies authors agreed that two month-old infants exhibit social smiles. However it is not clear if newborns exhibit different kinds of smiles during wake and active sleep to two month-old infants and if the communicative context can affect the quantity and quality of these smiles.The aim of this study was to test if different kinds of communication affects the amount and the quality of smiles during different behavioural states.Smiling behaviour was analyzed during interactive wake (IW) and active sleep (AS), in 40 newborns randomly assigned to 4 groups of 10 newborns each: continuous tactile communication group, discontinuous non periodic tactile communication group, discontinuous periodic tactile communication group, absent communication group. In the total sample the open/closed mouth (social/non social) smiles ratio was 38/5 during IW and 1/28 during AS (p < .001). Moreover these ratios were different between the four groups.Different kinds of tactile communication affect amount and quality of the smiles of newborns during IW and AS. Moreover the morphological difference of the smiles during IW and AS suggested that for newborns the smiling behaviour during IW could have a social meaning, as it does for two month-old infants.     

The breathing bear with preterm infants: Effects on sleep,respiration, and affect

This study investigated the sleep/wake states, respiration, and affective behaviors of premature infants who were provided à “breathing” bear in the isolette from 33 to 35 weeks conceptional age (CA). The Breathing Bear is à source of rhythmic stimulation that is optional for the infants. Its “breathing” reflects the breathing rate of the individual infant. At 33 weeks CA, 27 premature infants were provided à Breathing Bear (BrBr) and 26 were given à Non-Breathing Bear (N-BrBr). At 35 weeks, interfeed observations for an average of 1.7 hours were made of the babies' states and state-specific behaviors, along with respiration recordings. By 35 weeks, the BrBr babies showed less wakefulness, more quiet sleep, fewer startles in quiet sleep, and less crying than the N-BrBr babies. In addition, they were more likely to smile and N-BrBr babies were more likely to grimace in active sleep. These findings replicate and extend previous reports of effects of the Breathing Bear on neurobehavioral organization. They also suggest that less negative affect is expressed by the BrBr babies; and they point to the importance of future study of preterm infants' affective expressions, both in sleep and in waking.     

Mother–child interaction and sleep regulation in one‐year‐olds

The regulation of sleep–wake states is controlled not only by biological mechanisms but by care‐giving context as well. In this study the association between mother–child relationship and the infant's sleep was examined. Thirty‐seven 12‐month‐olds and their mothers participated in a 10‐minute laboratory play episode. The dyadic interaction was coded with the Early Parent–Child Relational Assessment (Clark, 1985) and with the Emotional Availability scales (Biringen, Robinson, & Emde, 1993). The child's sleep was measured at home with a small‐computerized activity monitor. Although mothers' behavior was not related to the child's sleep, infants who were more responsive in the play episode woke up more frequently compared to infants who were less involved in the interaction. The link between social‐emotional competency and fragmented sleep, among nonrisk infants, could be an age‐related phenomenon. ©2001 Michigan Association for Infant Mental Health.     

Goodness of fit between prenatal maternal sleep and infant sleep: Associations with maternal depression and attachment security

The current study prospectively examined the ways in which goodness of fit between maternal and infant sleep contributes to maternal depressive symptoms and the mother-child relationship across the first years of life. In a sample of 173 mother-child dyads, maternal prenatal sleep, infant sleep, maternal depressive symptoms, and mother-child attachment security were assessed via self-report, actigraphy, and observational measures. Results suggested that a poor fit between mothers’ prenatal sleep and infants’ sleep at 8 months (measured by sleep diary and actigraphy) was associated with maternal depressive symptoms at 15 months. Additionally, maternal depression mediated the association between the interplay of mother and infant sleep (measured by sleep diary) and mother-child attachment security at 30 months. Findings emphasize the importance of the match between mother and infant sleep on maternal wellbeing and mother-child relationships and highlight the role of mothers’ perceptions of infant sleep.     

Rhythmic organization of heart rate in breast-fed and bottle-fed newborn infants

Heart rates and behavioural states of 14 breast-fed and 14 bottlefed newborn infants were assessed every 30 seconds for 2 continuous hours. The 240 observations of heart rate were treated as time-series data and spectrum-analysed for behavioural rhythmicities. Of the 28 infants, 25 showed reliable cycles in heart rate; 22 of the 25 infants showed a dominant frequency with a 30–60 min periodicity, one that approximates the basic-rest activity cycle (BRAC). In addition to this basic cycle, additional higher frequency cycles in long-term heart rate variability were evident in the spectra of many infants. Breast-fed newborns had greater numbers of reliable cycles in heart rate than bottle-fed newborns. Further, breast-fed newborns had lower overall mean heart rates and lower mean heart rates in Quiet and Active Sleep states than bottle-fed newborns. Bottle-fed newborns were observed more often in Quiet Sleep than breast-fed newborns. Without knowledge of the specific mechanisms causing these behavioural differences, the results of this study suggest that the context in which breast-feeding occurs results in a more complex and energy-efficient pattern of behavioural organization than the context of bottle-feeding.     

Possible contribution of better maternal psychological well-being to the acquisition of sleeping through the night in infants during the early postpartum period

The objective of this study was to elucidate whether better maternal psychological well-being contributes to the acquisition of “sleeping through the night” (STN) in infants during the early postpartum period. Fifty-two primiparous mothers completed the General Health Questionnaire-28 (GHQ-28) in the third trimester (prenatal) and when the conceptional ages of their babies reached 8–9 weeks (hereafter, 2 months), 12–13 weeks (3 months), and 16–17 weeks (4 months). They also recorded babies’ nocturnal sleep patterns in a timetable for 5 consecutive days each month postpartum. “Regular STN” was defined when the mean of longest nocturnal sleep duration for 5 consecutive days was > 8 h or between 6 and 8 h with < 1.0 nocturnal awakenings. According to these criteria, a total of 14 infants (27 %) acquired regular STN at 4 months (referred to as “STN infants”), with STN infants showing a marked increase in longest nocturnal sleep duration and a decrease in nocturnal awakenings from 2 to 3 months of age. The mothers of STN infants demonstrated steady reductions in postnatal GHQ-28 scores and had significantly lower prenatal GHQ-28 scores compared with the mothers of non-STN infants (3.7 ± 3.0 vs. 6.4 ± 4.1, p = 0.027). In random forest models for binomial classification, both prenatal and postnatal (at 4 months) GHQ-28 scores were identified as significant covariates for distinguishing STN infants, and other important covariates, including weeks of delivery, stepfamily, birth weight of the infant, and maternal co-sleeping at bedtime, were selected. Among these covariates, maternal co-sleeping at bedtime had relatively stronger correlations with both STN infants (r = − 0.440) and prenatal maternal GHQ-28 scores (r = 0.377). In conclusion, because prenatal maternal psychological well-being was thought to predict the acquisition of STN in infants, infants born from mothers with better psychological well-being appear to have some advantages in acquiring STN. These cross-lagged correlations suggest that the pathway from mothers to infants may be mediated by certain parenting behaviors, such as maternal co-sleeping at bedtime.     

Sleep and Attachment in Preterm Infants

Infants born preterm are at elevated risk for socioemotional difficulties; however, factors contributing to this risk are largely understudied. Within the present study, we explored infant sleep as a biosocial factor that may play a role in infant socioemotional development. Within a prospective longitudinal design, we examined parent‐reported sleep patterns and observed parenting quality as predictors of infant–mother attachment in 171 infants born preterm. Using structural equation modeling, we examined main effect and moderator models linking infant sleep patterns and parenting with attachment security. Sleep patterns characterized by more daytime sleep and positive/responsive parenting predicted infant attachment security. Parent‐reported nighttime sleep patterns were unrelated to attachment in this sample of infants born preterm. These results indicate that daytime sleep and parenting quality may be important for emerging attachment relationships in infants born preterm.     

Prenatal Cocaine Exposure and Infant Sleep at 7 Months of age: The Influence of the Caregiving Environment

The primary goal of this study was to examine sleep problems in a sample of cocaine-exposed 7-month-old infants and to determine if maternal psychopathology mediated any existing association between substance exposure and sleep behaviors. We also examined the differences in sleep behaviors of cocaine-exposed infants in parental custody and cocaine-exposed infants in nonparental custody. Participants were 65 cocaine-exposed and 53 nonexposed infants and their primary caregivers who were recruited at delivery and assessed at 7 months of infant age. As expected, women who used cocaine during pregnancy had more psychiatric symptoms than nonusers. Prenatal exposure to heavier amounts of cocaine was significantly related to more severe sleep difficulties, and maternal anxiety mediated this association. Approximately 28% of cocaine mothers lost custody of their infants by 7 months of age. Nonmaternal caregivers had significantly fewer symptoms of psychopathology than the cocaine-using women who retained custody of their children. Infants who were in nonparental care at 7 months of age also had less severe sleep problems than did infants who remained in parental care.     

Age attenuates noise and increases symmetry of head movements during sleep resting-state fMRI in healthy neonates,infants, and toddlers

Newborns produce spontaneous movements during sleep that are functionally important for their future development. This nuance has been previously studied using animal models and more recently using movement data from sleep resting-state fMRI (rs-fMRI) scans. Age-related trajectory of statistical features of spontaneous movements of the head is under-examined. This study quantitatively mapped a developmental trajectory of spontaneous head movements during an rs-fMRI scan acquired during natural sleep in 91 datasets from healthy children from ∼birth to 3 years old, using the Open Science Infancy Research upcycling protocol. The youngest participants studied, 2–3 week-old neonates, showed increased noise-to-signal levels as well as lower symmetry features of their movements; noise-to-signal levels were attenuated and symmetry was increased in the older infants and toddlers (all Spearman's rank-order correlations, P < 0.05). Thus, statistical features of spontaneous head movements become more symmetrical and less noisy from birth to ∼3 years in children. Because spontaneous movements during sleep in early life may trigger new neuronal activity in the cortex, the key outstanding question for in vivo, non-invasive neuroimaging studies in young children is not “How can we correct head movement better?” but rather: How can we represent all important sources of neuronal activity that shape functional connections in the still-developing human central nervous system?     

Sleep-competing behaviours among Australian school-attending youth: Associations with sleep,mental health and daytime functioning

Sleep problems are highly prevalent among school-attending youth, and impact on school performance and outcomes. Sleep-competing behaviours are likely factors in the inadequate sleep time and related functional outcomes observed in this population. We examined a range of sleep-competing behaviours and their associations with sleep variables in Australian school-attending youth. We also assessed whether these behaviours indirectly affected mental health and daytime functioning through poorer sleep quality. A total of 353 school-attending youth (mean age = 14.6 years, 53% female) were recruited from high schools in Australia, and completed a range of self-report measures. Approximately 50% of the youth obtained sub-optimal levels of sleep and reported having a problematically long sleep onset latency. Sleep competing behaviours, related and unrelated to electronic media use, were reported as occurring frequently, and were associated with a range of sleep variables. These behaviours were also related to poorer mental health and daytime sleepiness, with this association explained by indirect effects through sleep quality. Sleep-competing behaviours are prevalent on school nights in Australian youth, and may have adverse associations with mental health and functioning. Prevention and intervention programs might address the risk factors identified in the current study.     

Memory in 3‐month‐old infants benefits from a short nap

A broad range of studies demonstrate that sleep has a facilitating role in memory consolidation (see Rasch & Born, 2013 ). Whether sleep‐dependent memory consolidation is also apparent in infants in their first few months of life has not been investigated. We demonstrate that 3‐month‐old infants only remember a cartoon face approximately 1.5–2 hours after its first presentation when a period of sleep followed learning. Furthermore, habituation time, that is, the time to become bored with a stimulus shown repetitively, correlated negatively with the density of infant sleep spindles, implying that processing speed is linked to specific electroencephalographic components of sleep. Our findings show that without a short period of sleep infants have problems remembering a newly seen face, that sleep enhances memory consolidation from a very early age, highlighting the importance of napping in infancy, and that infant sleep spindles may be associated with some aspects of cognitive ability.     

“Ghosts in the Nursery:” Infant sleep and sleep‐related cognitions of parents raised under communal sleeping arrangements

In an experiment of nature, a normal cohort of parents who were raised under communal sleeping arrangements (CSA) in Israeli kibbutzim are raising their infants at home under home‐based family sleeping arrangements. The present study focused on exploring the links between the early sleep experiences of CSA parents and their present sleep‐related beliefs and behaviors. In particular, the study assessed whether the cognitions of CSA parents regarding infant sleep differ from cognitions of parents who were raised under home‐based family sleeping arrangements. Furthermore, parental soothing methods and infant sleep patterns were compared. One hundred forty‐one families participated in this study. The children's ages ranged between 4.5 to 30 months. Parental cognitions were evaluated by two questionnaires. Infant sleep was assessed by a questionnaire and by daily parental reports. As expected, CSA parents were more likely than were control parents to: (a) interpret infant night wakings as a sign of distress and (b) actively soothe their infants at bedtime, co‐sleep with them, and report more night wakings of their infants. These findings support the hypothesis that early childhood sleep‐related experiences of parents (“Ghosts in the Nursery”) influence their parental sleep‐related cognitions that in turn affect infant sleep patterns.     

Neonatal functioning and the sudden infant death syndrome

A male infant, diagnosed as a Sudden Infant Death Syndrome (SIDS) at 5 months, 3 weeks, had been extensively tested as a part of a larger sample in a longitudinal study. The longitudinal sample was comprised of 137 clinically normal neonates, born to intact upper middle-class families, living in a large metropolitan area. A neonatal assessment consisted of 5 hours of polygraphic recordings of heart and respiratory rate during sleep and waking cycles, and 1 hour of behavioral testing. At 3 months of age the infant was observed for 12 hours in the home. Retrospective analyses of these data suggested that: (a) neonatal respiratory behavior during sleep did not distinguish this infant from a sample of control infants; (b) the infant lacked strength in movements requiring the involvement of shoulder and neck muscles (head lift from a prone position); and (c) informal observations by skilled and experienced observers distinguished this infant from the sample of controls.     

Yawning frequency and distribution in preterm and near term infants assessed throughout 24-h recordings

Yawning has been observed in foetuses and preterm infants. The aim of this study was to assess the frequency and the 24 h distribution of yawning in preterm infants.Twelve low-risk infants between 31 and 40 weeks of post-conceptional age (PCA) were continuously video-recorded for 24 h in their incubator. Spontaneous yawning was defined as opening of the mouth to its full extension in a dramatic stretch movement.The results showed that the rate of yawning across the 24-h period was 1.10/h. The highest incidence of yawns was in the waking motility pattern when compared to active sleep or quiet sleep motility patterns.Between 31 and 40 weeks, yawn incidence significantly decreased mainly during the day. The marked decrease in yawn frequency with age may be related to the development of circadian and homeostatic control of sleep and wake.     

Depressed mothers' newborns show less discrimination of other newborns' cry sounds

Newborns' crying in response to the cry of another newborn has been called an empathetic response. The purpose of this study was to determine whether newborns of depressed mothers showed the same response. Newborns of depressed and non-depressed mothers were presented with cry sounds of themselves or other infants, and their sucking and heart rate were recorded. The newborns of non-depressed mothers responded to the cry sounds of other infants with reduced sucking and decreased heart rate. In contrast, the newborns of depressed mothers did not show a change in their sucking or heart rate to the cry sounds of other infants. This lesser attentiveness/responsiveness to other infants' cry sounds may predict their later lack of empathy.     

Mother's prenatal and postpartum depression symptoms and infant's sleep problems at 6 months

Mother's prenatal and postpartum depression have been associated with infant's sleep problems. This study aimed to analyze (a) the effects of mother's prenatal and postpartum depression symptoms, including the effects of prenatal and postpartum anxiety and depression scores of the Edinburgh Postnatal Depression Scale (EPDS), on infant's sleep problems at 6 months, and (b) the interaction effect between mother's prenatal and postpartum depression symptoms and infant's sex on infant's sleep problems at 6 months. The sample was comprised of 164 mother–infant dyads whose mothers completed measures of depression at the third trimester of pregnancy, 2 weeks, 3 and 6 months postpartum and a measure of infant's sleep problems at 6 months (CSHQ-I). Mother's prenatal depression symptoms, specifically depression scores of the EPDS, predicted more infant's sleep anxiety and daytime sleepiness, while mother's depression symptoms at 2 weeks postpartum, specifically anxiety scores of the EPDS, predicted more bedtime resistance and CSHQ-I total scores at 6 months. Boys of mothers with more prenatal depression symptoms presented more sleep anxiety at 6 months. Both mother's prenatal and early postpartum depression symptoms have a negative effect on the emergence of infant's sleep problems. Additionally, boys seem more vulnerable to mother's prenatal depression symptoms.     

Development of sleep/wake,activity and temperature rhythms in newborns maintained in a neonatal intensive care unit and the impact of feeding schedules

Biological rhythms in infants are described as evolving from an ultradian to a circadian pattern along the first months of life. Recently, the use of actigraphy and thermistors with memory has contributed to the understanding of temporal relations of different variables along development. The aim of this study was to describe and compare the development of the rhythmic pattern of wrist temperature, activity/rest cycle, sleep/wake and feeding behavior in term and preterm newborns maintained in a neonatal intensive care unit (NICU).MethodsNineteen healthy preterm and seven fullterm newborns had the following variables monitored continuously while they were in the NICU: activity recorded by actigraphy, wrist temperature recorded with a thermistor and observed sleep and feeding behavior recorded by the NICU staff with diaries. Subjects were divided in 3 groups according to their gestational age at birth and rhythmic parameters were compared.ResultsA dominant daily rhythm was observed for wrist temperature since the first two weeks of life and no age relation was demonstrated. Otherwise, a daily pattern in activity/rest cycle was observed for most preterm newborns since 35 weeks of postconceptional age and was more robust in term babies. Feeding and sleep/wake data showed an almost exclusive 3 h rhythm, probably related to a masking effect of feeding schedules.ConclusionsWe found that wrist temperature develops a daily pattern as soon as previously reported for rectal temperature, and with acrophase profile similar to adults. Moreover, we were able to find a daily rhythm in activity/rest cycle earlier than previously reported in literature. We also suggest that sleep/wake rhythm and feeding behavior follow independent developmental courses, being more suitable to masking effects.     

Culture and the organization of infant sleep: A study in the Netherlands and the U.S.A.

This study investigates differences in the amount and structure of infant sleep in two cultural places with previously documented, divergent parental beliefs and practices. Eight-month-old infants (n = 24 per site) were recruited from towns in the Netherlands and the eastern U.S.A. To evaluate sleep, infants’ physical activity was recorded at home for 24 h using a miniature actigraph, while parents kept a diary of infant activities. Measures derived from actigraphy include total sleep, longest sleep episode, longest wake episode, number of sleep episodes, and percent of sleep during nighttime, as well as time in the stages of Quiet and Active Sleep. Measures based on the parental diaries include most of these aspects as well, except those related to sleep stages. Results based on the more precise actigraphy method indicate that (1) the Dutch infants averaged 13.65 h of sleep per 24 h, 1.67 h more than the U.S. infants; this difference was mostly due to daytime sleep; (2) The Dutch infants’ longest wake episode averaged less than that of the U.S. infants, while their longest sleep episode appeared slightly longer. (3) The Dutch infants, compared to the U.S. sample, spent more time in the Quiet, rather than the Active phase of sleep; (4) They began their Quiet sleep earlier in the evening than did their U.S. counterparts. Measures derived from parental diaries are largely in agreement with the actigraph findings. These results are consistent with reported and observed practices and beliefs in the two communities. The pattern of differences – less apparent maturity among the Dutch in the amount of sleep, but greater apparent maturity in the structure of sleep -- illustrates that behavioral and neurological maturity can be assessed only in the context of the developing child’s adaptation to the specific demands and affordances of the culturally structured developmental niche.     

Rapid eye movement (REM) in premature neonates and developmental outcome at 6 months

Different aspects of early sleep organization have been associated with subsequent development in premature infants. The aim of the present study was to assess the relations between rapid eye movement (REM) activity in premature neonates and infants' developmental outcomes at 6 months. Participants were 81 premature infants (47 males). Sleep-wake states and REM were observed across 4 consecutive evening hours (7-11 PM) in 10-s frames when infants were between 32 and 36 weeks post-menstrual age. Developmental outcome was assessed at 6 months with the mental development index (MDI) of the Bayley II. Infants with low-REM activity spent more time in less growth-promoting states, including crying and unfocused alert states in the neonatal period and had lower MDI scores at 6 months corrected age compared to infants with high-REM. Differences between the high- and low-REM groups were independent of neonatal medical risk. Low-REM activity may serve as an indicator of developmental risk among premature neonates.     

Detecting impossible changes in infancy: a three-system account

Can infants detect that an object has magically disappeared, broken apart or changed color while briefly hidden? Recent research suggests that infants detect some but not other 'impossible' changes; and that various contextual manipulations can induce infants to detect changes they would not otherwise detect. We present an account that includes three systems: a physical-reasoning, an object-tracking, and an object-representation system. What impossible changes infants detect depends on what object information is included in the physical-reasoning system; this information becomes subject to a principle of persistence, which states that objects can undergo no spontaneous or uncaused change. What contextual manipulations induce infants to detect impossible changes depends on complex interplays between the physical-reasoning system and the object-tracking and object-representation systems.