Infant sleep-wake behaviors at two weeks,three and six months

Although infant sleep-wake behavior presents several developmental changes during the first six months, literature lacks on reference values and few studies have explored the role of individual change and stability on infant sleep-wake behavior during the first six months. This study aimed (1) to describe infant sleep-wake behaviors during the 24-h period, day and night, at two weeks, three, and six months, (2) and to explore developmental changes and the role of individual change and stability on infant sleep-wake behaviors from two weeks to six months. Ninety-four primiparous mothers completed measures on infant sleep-wake behaviors at two weeks, three and six months. Significant developmental changes were found on infant sleep-wake behaviors from two weeks to six months. Two-week-old infants sleep 13.3 h, spend 8.7 h awake, awake 6.1 times, have 0.4 h of latency to sleep, and 3.2 h of longest sleep period. Three-month-old infants sleep 13.0 h, spend 9.2 h awake, awake 5.5 times, have 0.4 h of latency to sleep, and 5.2 h of longest sleep period. Six-month-old infants sleep 12.2 h, spend 10.0 h awake, awake 5.2 times, have 0.4 h of latency to sleep, and 5.6 h of longest sleep period. Significant individual change and stability were also found on infant sleep-wake behaviors from two weeks to six months. Despite significant developmental and individual changes, individual stability explains a significant amount of the variance on infant sleep-wake behaviors over the first six months of life.     

Maternal perceptions of the sleep patterns of premature infants at seven months corrected age compared to full-term infants

It has been reported that 83%–87% of full-term infants regularly sleep through the night (from midnight to 5 a.m.) by 6 months of age, but there is little information about the sleep patterns of premature infants. The purpose of the current study was to identify maternal perceptions of the sleep patterns of premature infants. Parents of 32 premature infants with birth weight below 1,750 gm and of 13 full-term infants completed a 24-hour sleep record in 30-minute epochs for 1 week at 7 months of chronological (term) or corrected age (premature). Mean birth weight of premature infants was 1,278 ± 340 gm, with a gestational age of 30.4 ± 2.7 weeks. The daily total sleep time, longest sleep segment, frequency of sleep-wake transitions, and percentage of night sleep (8 p.m.–8 a.m.), averaged from the 1-week sleep record and number of night wakenings per week, were used as indicators of sleep patterns. The longest reported sleep segments of premature infants were significantly shorter than those of full-term infants (8.2 ± 2 hours versus 9.6 ± 1 hour, p < 0.01) and the number of night wakenings per week was significantly greater (3.13 ± 3 versus 0.54 ± 7, p < 0.005). Total reported sleep time, percentage of night sleep, and sleep-wake transitions did not differ significantly between premature and full-term infants. However, analysis of feeding events revealed that premature infants received significantly more feedings between midnight and 5 a.m. (M = 0.31 + 3 versus M = 0.06 + 1, p < 0.001). We conclude that sleep pattern diaries kept by parents indicate that premature infants have developed a diurnal sleep rhythm by 7 months corrected age, but they still have shorter sleep segments and they awaken more during the night than term infants.     

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.     

Sleep arrangements and night waking at 6 and 12 months in relation to infants' stress‐induced cortisol responses

The objective of this short‐term longitudinal study was to examine the concurrent and prospective associations of infants' sleep arrangements and night waking with cortisol responses to an inoculation at 6 and 12 months, controlling for several key covariates. To our knowledge, this was the first study to concurrently and prospectively link proximity in sleep arrangements and night waking to physiological stress reactivity. A sample of 92 mother–infant dyads participated in the study when the infants were 6 and 12 months of age, although sample sizes were reduced for some analyses. Both proximal cosleeping arrangements and more frequent night wakings' were associated concurrently with an increased cortisol response to inoculations at both ages. Night waking at 6 months also was associated with a slightly increased cortisol response to inoculation at 12 months. Results aimed at exploring the direction of influence suggested that cosleeping and night waking may influence infant stress physiology rather than the reverse. Adaptive and maladaptive implications of infants' nocturnal experiences and greater stress‐induced cortisol responses are discussed. Copyright © 2009 John Wiley & Sons, Ltd.     

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.     

Maternal perception of infant intentionality at 4 and 8 months

This study examines the degree to which mothers perceive infants as intentional and the relations among perception of intentionality, background variables, maternal emotional adjustment, and maternal interactive style. Forty mother-infant dyads were assessed when the infants were 4 months old, and 34 were retested at 8 months. Parent perception of infant intentionality (PPII) was measured via a rating of videotaped segments of infant behavior and an interview. Intentionality scores showed acceptable internal consistency and were positively intercorrelated at each age and across age. The two measures were aggregated to form an index of PPII at each age. Higher educational attainment was associated with lower PPII scores, experience with infants was associated with higher PPII scores, and academic knowledge about child development was not related to PPII. Mothers with more symptoms of anxiety had lower PPII scores, but high maternal separation anxiety was associated with higher PPII scores. Maternal symptoms of depression had a complex relation to PPII scores. Mothers rated as sensitive in mother-infant interactions had higher PPII scores. These variables accounted for 34% of the variance in PPII at 4 months and 49% at 8 months. There were also group differences: Mothers of 8-month-olds had higher PPII scores than mothers of 4-month-olds, mothers of girls had higher PPII scores than mothers of boys, and mothers attributed more intentionality in episodes with girls than in episodes with boys. The results are discussed in relation to mechanisms whereby PPII interacts with aspects of the parent and infant.     

Fetal SSRI antidepressant exposure and infant sleep: Findings from the MPEWS pregnancy cohort study

This longitudinal study examines the association between fetal Selective Serotonergic Reuptake Inhibitor antidepressant exposure and infant sleep behaviours at six and 12 months of age and focus on three of the most commonly prescribed antidepressants in pregnancy.This study utilises data on 698 women recruited at less than 20 weeks of pregnancy and are followed up at six and 12 months postpartum. Women were recruited into one of three groups: those taking either sertraline, citalopram or escitalopram antidepressants in pregnancy (n = 85); women with a depressive disorder who were not taking antidepressants (non-medicated depressed, NMD; n = 82); and, and a control group of women (n = 531). At six and 12 months, data were collected on breastfeeding and sleep location and infant sleep was measured using the Brief Infant Sleep Questionnaire. Antidepressants sertraline, escitalopram and citalopram were not associated with increased infant waking or time awake. However, sertraline was associated with longer time for an infant to go to sleep.This study provides reassurance that SSRI antidepressants and, in particular, sertraline, escitalopram and citalopram are not associated with infant sleep behaviours that are commonly regarded as problematic including night waking. Further replication of these findings, including with direct measures of infant sleep, are recommended.     

“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.     

The sleep patterns and problems of clinically anxious children

Childhood sleep problems have been associated with a range of adverse cognitive and academic outcomes, as well as increased impulsivity and emotional disorders such as anxiety and depression. The aim of the study was to examine subjective reports of sleep-related problems in children with anxiety disorders during school and weekend nights. Thirty-seven children with clinically-diagnosed anxiety disorders and 26 non-clinical children aged 7-12 years completed an on-line sleep diary to track sleep patterns across school nights and weekend nights. Anxious children reported going to bed significantly later (p = 0.03) and had significantly less sleep (p = 0.006) on school nights compared to non-anxious children. No significant differences in sleep onset latency, number of awakenings or time awake during the night, daytime sleepiness, or fatigue were found between the two groups. On the weekends, anxious children fell asleep quicker and were less awake during the night than on weeknights. School-aged anxiety disordered children showed a sleep pattern that differs from their non-anxious peers. Although the mean 30 min less sleep experienced by anxious children may initially seem small, the potential consequences on daytime performance from an accumulation of such a sleep deficit may be significant, and further investigation is warranted.     

Sleep arrangements and maternal adaptation in infancy

Among the many decisions that parents make regarding child‐rearing practices, an important one involves sleep arrangements. Little is known about the relationship between chosen sleep arrangements, parents' adaptation to these choices, parental sleep quality, spousal support, and parental distress. Forty‐five mothers and fathers with infants 1 to 24 months old completed measures of parental attitudes and practices regarding sleep arrangements. Shared sleep with one's infant was associated with poorer parental adaptation to infant sleep disruption, and this was true even when parents endorsed the practice of sharing sleep with their infants. Among mothers, shared sleep and poorer adaptation to infant sleep were significantly associated with elevated depressive symptoms, poorer sleep quality, and spousal criticism directed to mothers about where the infant slept during the night. For mothers, criticism from their spouses about where the baby slept, mothers' sleep quality, and depressive symptoms mediated the link between sleep arrangements and maternal adaptation. Results emphasize the importance of taking into account individual differences in the quality of parents' adaptation to infant sleep behavior, a construct largely ignored in the child sleep literature to date, in understanding linkages between infant sleep quality and infant–parent outcomes.     

Maternal speech to infants at 1 and 3 months of age

The goal of this study was to assess maternal speech and in relation to changes in infant social behavior occurring around the second month post birth. Sixty infants interacted with their mother at 1 and 3 months of age in a face-to-face context. At 3 months, infants gazed, smiled, and positively vocalized significantly more than at 1 month. These findings point to a transition in infant social behavior at around the second month post birth. In addition, maternal speech to infants increased between these times in both amount and complexity, possibly in response to an increase in infant social behavior. Maternal speech was related to infant positive vocalizing at 3 months, suggesting mothers especially monitored infant vocalizing at 3 months. Individual differences in maternal speech were stable across visits.     

Precursors of social emotional functioning among full-term and preterm infants at 12 months: Early infant withdrawal behavior and symptoms of maternal depression

This study forms part of a longitudinal investigation of early infant social withdrawal, maternal symptoms of depression and later child social emotional functioning. The sample consisted of a group of full-term infants (N = 238) and their mothers, and a group of moderately premature infants (N = 64) and their mothers. At 3 months, the infants were observed with the Alarm Distress Baby Scale (ADBB) and the mothers completed the Edinburgh Postnatal Depression Scale (EPDS). At 12 months, the mothers filled out questionnaires about the infants’ social emotional functioning (Infant Toddler Social Emotional Assessment and the Ages and Stages Questionnaire-Social Emotional). At 3 months, as we have previously shown, the premature infants had exhibited more withdrawal behavior and their mothers reported elevated maternal depressive symptoms as compared with the full-born group. At 12 months the mothers of the premature infants reported more child internalizing behavior. These data suggest that infant withdrawal behavior as well as maternal depressive mood may serve as sensitive indices of early risk status. Further, the results suggest that early maternal depressive symptoms are a salient predictor of later child social emotional functioning. However, neither early infant withdrawal behavior, nor gestational age, did significantly predict social emotional outcome at 12 months. It should be noted that the differences in strength of the relations between ADBB and EPDS, respectively, to the outcome at 12 months was modest. An implication of the study is that clinicians should be aware of the complex interplay between early infant withdrawal and signs of maternal postpartum depression in planning ports of entry for early intervention.     

Sleep disorders in the first 18 months of life: Hypothesis on the role of mother-child emotional exchanges

Sleep disturbances of infancy (troubles in falling asleep, in the duration of sleep, night waking) are now the subject of renewed interest. Recently, these sleep problems in babies and young children seem to have increased in frequency and severity. A pilot study of sleep disorders is underway at the child department of the Hopital de la Poterne des Peupliers and involves more than 80 children aged 0–18 months. Twenty-nine infants have been selected from this cohort with severe and persistent sleep disorders that began in the first 18 months of life. In the absence of a control group, all cases were selected carefully. Some of the characteristics of these children are discussed: Age, sex, associated troubles, modalities of soothing, effect of hypnotic drugs, development under treatment. Some of these children are noted to be very active. Quite often, the pregnancy was marked by a traumatic event or by depression or anxiety in the mother. During evaluation of the mother-child interaction, one often notes a withdrawal of the mother's cathexis toward her child, which can go along with hyperstimulation in the relationship. This withdrawal concerns the emotional and fantasied dimensions of the interaction. The child's reactions and initiatives can be paralleled with the mother's speech, motor, and emotional attitudes. Thus, sleep disorders in early childhood represent an opportunity to observe the modalities of emotional exchange between mother and child and a methodologically interesting situation for the assessment of mother-child relationships.     

Napping alone in the snow and cuddling with mommy at night: An exploratory,qualitative study of Norwegian beliefs on infant sleep

This study addresses Norwegian infants’ sleeping places during the day and night. In the first part we asked the general public to indicate where they think infants should sleep by placing stickers on a depiction of different sleeping places. This revealed that infants were expected to predominantly sleep outside in a stroller during the day and either bedshare, room share or sleep independently from their parents at night. Interviews with Norwegian mothers confirmed these patterns and revealed that mothers emphasized the benefits of fresh air and being out in nature. They expressed valuing independence, though their opinions on how this could be achieved diverged, some proposing independent, other co-sleeping. Other outcomes of sleeping arrangements were rarely mentioned. Some, particularly mothers whose children bedshared or had different sleeping places from one night to the other or throughout the night, emphasized the infants’ right to choose how to sleep. None of the mothers endorsed letting infants cry themselves to sleep but many mentioned the importance of the child feeling secure. We argue that the seemingly contradictory sleeping patterns is in line with cultural values for independence, social cohesion and a love of nature.     

Night waking in 6-month-old infants and maternal depressive symptoms

Relations between night waking in infants and depressive symptoms in their mothers at 6 months postpartum were examined using the data from the National Institute for Child Health and Human Development Study of Early Child Care. Although more depressive symptoms were only weakly correlated with a higher frequency of infant waking, longer wake times, and more total time awake, the rate of clinically significant depression scores was about double in mothers of chronically waking infants in comparison with mothers whose infants did not awaken during the night. The value of comparing subgroups to elucidate relations identified through correlations is discussed.     

Diet and gender influences on processing and discrimination of speech sounds in 3- and 6-month-old infants: a developmental ERP study

Early post-natal nutrition influences later development, but there are no studies comparing brain function in healthy infants as a function of dietary intake even though the major infant diets differ significantly in nutrient composition. We studied brain responses (event-related potentials; ERPs) to speech sounds for infants who were fed either breast milk (BF), milk-based formula (MF), or soy formula (SF) during the first 6 months of life. Two syllables presented in an oddball paradigm elicited a late positive wave (P350) from temporal and frontal brain regions involved in language processes. All groups showed significantly greater response amplitudes to the infrequent syllable across sites at 3 months and frontally at 6 months, but significant discrimination at temporal sites was only observed at 6 months in BF infants. Decreases in response amplitudes from 3 to 6 months were greater for the frequently presented syllable, most prominent in BF infants, and greater in females than males. The results indicate greater syllable discrimination in BF than formula-fed infants, but whether this can be attributed to dietary influences alone remains unclear. Feeding method and background factor differences between breastfed and formula-fed infants may also contribute to the observed differences. The general absence of differences between formula-fed groups is notable and suggests that milk-based formula and soy formula equally support brain development and function during the first post-natal 6 months. Finally, the results indicate gender differences in the development of neural and temporal processes involved in sensory discrimination, and suggest that at 6 months these processes are better developed in females.     

Relationship between sleep disturbance,depression and anxiety in the 12 months following a cardiac event

We aimed to assess the prevalence of sleep disturbance in a cardiac patient population over a 12-month period and assess its relationship with treatment adherence, self-efficacy, anxiety and depression. A total of 134 patients consecutively admitted to two Australian hospitals after acute myocardial infarction (31%), or to undergo bypass surgery (29%) or percutaneous coronary intervention (40%) were interviewed at six weeks and four and 12 months. Sleep disturbance was measured using a recode of the Beck Depression Inventory (v.2) item 16. Anxiety and depression were assessed by the Hospital Anxiety and Depression Scale. Sleep disturbance was highly prevalent (69%) at 6 weeks but was not associated with 12-month psychological outcomes. Path analysis revealed that sleep disturbance at 4 months was, however, associated with reduced treatment adherence and self-efficacy, and higher anxiety and depression scores at 12 months. The high prevalence of sleep disturbance in this study and its association with psychological outcomes may have adverse prognostic implications and possibly impede cardiac rehabilitation efforts.     

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.     

Infant affective responses to mother's still face at 6 months differentially predict externalizing and internalizing behaviors at 18 months

This study investigated (a) stability and change in infant affective responses to the still-face interaction, (b) whether maternal depression affected infant responses, and (c) whether responses to the still-face interaction predicted toddler problem behaviors. Infants (63 girls and 66 boys) of European American mothers (67 depressed and 62 nondepressed) were observed in the still-face interaction at 2, 4, and 6 months. Affect and gaze were coded on a 1-s time base. There were stable individual differences in gazing away and in rates of negative affect. Developmental change occurred only for gazing away, which increased. At 18 months, infants who failed to smile at 6 months in the still-face interaction showed more externalizing-type behaviors than did other toddlers. Infants who failed to cry at 6 months showed fewer internalizing-type behaviors. Mothers' current depressive symptoms and infants' earlier responses to the still-face interaction made independent, comparable contributions to problem behaviors at 18 months.     

Effects of diet on early stage cortical perception and discrimination of syllables differing in voice-onset time: a longitudinal ERP study in 3 and 6 month old infants

The influence of diet on cortical processing of syllables was examined at 3 and 6 months in 239 infants who were breastfed or fed milk or soy-based formula. Event-related potentials to syllables differing in voice-onset-time were recorded from placements overlying brain areas specialized for language processing. P1 component amplitude and latency measures indicated that at both ages infants in all groups could extract and discriminate categorical information from syllables. Between-syllable amplitude differences—present across groups—were generally greater for SF infants. Responses peaked earlier over left hemisphere speech-perception than speech-production areas. Encoding was faster in BF than formula-fed infants. The results show that in preverbal infants: (1) discrimination of phonetic information occurs in early stages of cortical processing; (2) areas overlying brain regions of speech perception are activated earlier than those involved in speech production; and (3) these processes are differentially modulated by infant diet and environmental factors.