Infant Reactivity Research Articles

Maternal sensitivity moderates the impact of prenatal anxiety disorder on infant responses to the still-face procedure

Animal studies have demonstrated the interactive effects of prenatal stress exposure and postnatal rearing style on offspring capacity to manage stress. However, little is known about how parenting quality impacts the association between maternal prenatal anxiety and stress reactivity in human infants. This prospective study examined the impact of prenatal anxiety disorder and maternal caregiving sensitivity on infants’ responses to a standardised interactive stressor (still-face procedure). Eighty-four women completed a clinical interview during pregnancy to assess anxiety symptoms meeting DSM-IV diagnostic criteria. At infant age 7 months, maternal sensitivity to infant distress and infant negative affect were observed and coded during the still-face procedure. Maternal postnatal (concurrent) anxiety and depression were also assessed at this time. Results indicated a negative association between maternal sensitivity to infant distress and infant negative affect responses to the still-face procedure. An unexpected finding was a positive association between parity and infant reactivity. The main effect for sensitivity was qualified by a significant interaction, p < .05, suggesting that the impact of sensitivity was particularly marked among infants of women who experienced an anxiety disorder during pregnancy. This finding is consistent with a cumulative risk model suggesting that maternal prenatal anxiety and quality of maternal care act in concert to shape infant outcomes.

FKBP5 and resistant attachment predict cortisol reactivity in infants: Gene–environment interaction

Quality of the parent-infant attachment relationship influences physiological stress regulation. Genetic factors also contribute to the stress regulatory HPA-axis. Quality of attachment as an index of the rearing environment (measured with the Strange Situation Procedure, SSP), and HPA-axis related SNPs (BclI, rs41423247; TthIIII, rs10052957; GR-9β, rs6198; N363S, rs6195; ER22/23EK, rs6189 and 6190; and FKBP5, rs1360780) were hypothesized to be related to cortisol reactivity in the stressful SSP. In this large population based sample, FKBP5 rs1360780, but not GR haplotype, was related to cortisol reactivity. Moreover, we found a significant interaction effect for insecure-resistant attachment and FKBP5 rs1360780, indicating a double-risk for heightened cortisol reactivity levels in infants with one or two T-alleles of the FKBP5 SNP and an insecure-resistant attachment relationship with their mother. Findings are discussed from the perspective of gene-environment interaction.

Temperament trait of sensory processing sensitivity moderates cultural differences in neural response

This study focused on a possible temperament-by-culture interaction. Specifically, it explored whether a basic temperament/personality trait (sensory processing sensitivity; SPS), perhaps having a genetic component, might moderate a previously established cultural difference in neural responses when making context-dependent vs context-independent judgments of simple visual stimuli. SPS has been hypothesized to underlie what has been called inhibitedness or reactivity in infants, introversion in adults, and reactivity or responsivness in diverse animal species. Some biologists view the trait as one of two innate strategies-observing carefully before acting vs being first to act. Thus the central characteristic of SPS is hypothesized to be a deep processing of information. Here, 10 European-Americans and 10 East Asians underwent functional magnetic resonance imaging while performing simple visuospatial tasks emphasizing judgments that were either context independent (typically easier for Americans) or context dependent (typically easier for Asians). As reported elsewhere, each group exhibited greater activation for the culturally non-preferred task in frontal and parietal regions associated with greater effort in attention and working memory. However, further analyses, reported here for the first time, provided preliminary support for moderation by SPS. Consistent with the careful-processing theory, high-SPS individuals showed little cultural difference; low-SPS, strong culture differences.

Differential susceptibility to fathers' care and involvement: The moderating effect of infant reactivity

The differential susceptibility hypothesis suggests that children differ in their susceptibility to the influence of both positive and negative environmental factors. Children with reactive temperaments are hypothesised to be particularly susceptible to environmental influences, both for better and for worse. The present study sought to investigate whether infant temperament moderates the influence of fathers on child prosocial and problem behaviours. In a large prospective population study (Avon Longitudinal Study of Parents and Children), 5064 children were followed between the ages of six and 81 months (6¾ years). Infant temperament, child behaviours, and fathers’ involvement and depression were assessed.Although no overall moderating effect of reactive temperament was found for father involvement or depression, there was an interaction between reactivity, child gender, and father involvement. Girls with reactive temperaments were more susceptible to father involvement, showing significantly fewer problem behaviours and more prosocial behaviours when fathers were more involved, and more problem behaviours and fewer prosocial behaviours with less father involvement. The findings provide some support for the differential susceptibility hypothesis and extend existing findings to include effects of fathers’ involvement on positive and negative behavioural outcomes.

Emotional reactivity in infants with congenital heart defects: findings from a large case‐cohort study in Norway

Advances in medical treatment in recent years have led to dramatically improved survival rates of children with severe congenital heart defects (CHD). However, very little is known about the psychological consequences for these children, particularly during and after the early period of invasive treatment. In this study, we investigated the extent to which the severity of the CHD affects the child's emotional reactivity at 6 months of age. We linked prospective data from the Norwegian Mother and Child Cohort Study, conducted by the Norwegian Institute of Public Health with a nationwide medical CHD registry and identified 212 infants with CHD in a cohort of 61 299 infants. Mothers reported on their child's emotional reactivity at age 6 months by means of a standardized questionnaire. Infants with severe to moderate CHD had 60% higher odds for severe emotional reactivity (cut-off at the 85 percentile) compared with healthy infants, after controlling for important maternal and child confounders. Our study is the first to show elevated emotional reactivity in children with moderate to severe CHD, suggesting a need for special parental attention to soothe their distress. Follow-up studies will show whether this emotional reactivity is transient or an early marker of continuing emotional or behavioural problems.

Comparing emotional reactivity and regulation in infants born ELGA and VLGA

Emotional reactivity and regulation behaviors were compared in infants born extremely low gestational age (ELGA) and very low gestational age (VLGA) during the still-face procedure. Infants born ELGA demonstrated greater emotional reactivity and displayed less frequent gaze avoidance, more frequent gestures, and more self-comforting behaviors.

Salivary Cortisol and Behavioral State Responses of Healthy Newborn Infants to Tactile-Only and Multisensory Interventions

To compare changes in stress reactivity (measured via the biomarker salivary cortisol) and behavioral state in healthy newborn infants immediately following 1 of 2 interventions: (1) tactile-only stimulation or (2) a multisensory, auditory, tactile, visual, and vestibular stimulation with a control group. A randomized prospective design pilot study. Normal newborn nurseries of 2 midwestern perinatal centers. Forty healthy newborn infants receiving standard nursing care. Infants were randomly assigned to receive 15 minutes of tactile-only, auditory, tactile, visual, and vestibular, or no stimulation 30 minutes before feeding. Saliva samples were collected before, immediately following, and 10 minutes postintervention. Behavioral state was judged every minute. Tactile-only group infants had the largest increase in cortisol levels, followed by control group infants. In contrast, infants who received the multisensory intervention showed a significant steady decline in cortisol. Asleep was the predominant state for all 3 groups and cry was minimal. Tactile-only stimulation may increase infant stress reactivity while the benefit of the multisensory auditory, tactile, visual, and vestibular intervention may be in the reduction of infant stress reactivity. Interventions appeared to have minimal effect on stress reactivity based on behavioral state.

Contingency Learning and Reactivity in Preterm and Full-Term Infants at 3 Months.

Learning difficulties in preterm infants are thought to reflect impairment in arousal regulation. We examined relationships among gestational age, learning speed, and behavioral and physiological reactivity in 55 preterm and 49 full-term infants during baseline, contingency, and nonreinforcement phases of a conjugate mobile paradigm at 3 months corrected age. For all infants, negative affect, looking duration, and heart rate levels increased during contingency and nonreinforcement phases, whereas respiratory sinus arrhythmia (RSA, an index of parasympathetic activity) decreased and cortisol did not change. Learners showed greater RSA suppression and less negative affect than nonlearners. This pattern was particularly evident in the preterm group. Overall, preterm infants showed less learning, spent less time looking at the mobile, and had lower cortisol levels than full-term infants. Preterm infants also showed greater heart rate responses to contingency and dampened heart rate responses to nonreinforcement compared to full-term infants. Findings underscore differences in basal and reactivity measures in preterm compared to full-term infants and suggest that the capacity to regulate parasympathetic activity during a challenge enhances learning in preterm infants.

Effects of prenatal cocaine exposure on infant reactivity and regulation

The purpose of this study was to examine the role of prenatal cocaine exposure and associated risk factors on infant reactivity and regulation at 7 months of infant age. Participants consisted of 167 mother–infant dyads participating in an ongoing longitudinal study of prenatal cocaine exposure, who completed the arm restraint procedure at the 7-month assessment (87 cocaine exposed, 80 non-cocaine exposed). We hypothesized that cocaine exposed infants would display higher arousal or reactivity and lower regulation during a procedure designed to arouse anger/frustration. Results indicated that cocaine exposed infants were more reactive to increases in the level of stress from trial 1 to trial 2 but exhibited no change in the number of regulatory strategies as stress increased, unlike the control group infants. Infant birth weight moderated the association between cocaine exposure and infant regulation. Among cocaine exposed infants, those with lower birth weight displayed higher reactivity compared to those with higher birth weight. Contrary to expectations, there were no indirect effects between cocaine exposure and infant reactivity/regulation via environmental risk, parenting, or birth weight. Results are supportive of a teratological model of prenatal cocaine exposure for infant reactivity/regulation in infancy.

Expired nitric oxide and airway reactivity in infants at risk for asthma

Family histories of atopy, as well as histories of atopic dermatitis and food allergy, are important risk factors for an infant to have asthma. Although atopic sensitization appears to contribute to the development of asthma, it is unclear when the airways become involved with the atopic process and whether airway function relates to the atopic characteristics of the infant. We sought to evaluate whether atopic infants without prior episodes of wheezing have increased expired nitric oxide (eNO) levels and heightened airway reactivity. Infants with eczema were recruited, and atopic status was defined by specific IgE levels to foods or aeroallergens and total IgE levels. eNO, forced expiratory flow at 75% exhaled volume (FEF(75)), and airway reactivity to inhaled methacholine were measured in sedated infants. Airway reactivity was quantified by using the provocative concentration to decrease FEF(75) by 30%. Median age for the 114 infants evaluated was 10.7 months (range, 2.6-19.1 months). Infants sensitized to egg or milk compared with infants sensitized to neither egg nor milk had lower flows (FEF(75): 336 vs 285 mL/s, P < .003) and lower lnPC(30) (mg/mL) provocative concentrations to decrease FEF(75) by 30% (-0.6 vs -1.2, P < .02) but no difference in eNO levels. Infants with total serum IgE levels of greater than 20 IU/mL had higher eNO levels compared with infants with IgE levels of 20 IU/mL or less (14.6 vs 11.2 ppb, P < .023) but no difference in forced flows or airway reactivity. Our findings suggest that atopic characteristics of the infant might be important determinants of the airway physiology of forced expiratory flows, airway reactivity, and eNO.

The association between prenatal exposure to cigarettes and cortisol reactivity and regulation in 7-month-old infants.

We examined the association between prenatal exposure to cigarettes and adrenocortical responses to stress in 7-month-old infants. Cortisol levels were assessed twice prior to and twice following affect-eliciting procedures in 111 (59 exposed and 52 nonexposed) infants. Cortisol reactivity was defined as the difference between the peak poststressor cortisol level and the pretask cortisol level. Higher values indicated higher cortisol reactivity. Exposed infants had higher peak cortisol reactivity than nonexposed infants. There were no differences in pretask cortisol levels. Maternal hostility mediated the association between cigarette exposure and peak cortisol reactivity. Furthermore, infant gender moderated this association such that exposed boys had significantly higher peak cortisol reactivity than nonexposed infants or exposed girls. These findings provide additional evidence that prenatal cigarette exposure is associated with dysregulation during infancy and that early adverse, nonsocial experiences may have relatively long-lasting effects on cortisol reactivity in infants.

A procedure for the measurement of infant skin conductance and its initial validation using clap induced startle

Studies examining psychophysiologic markers of infant emotional development abound. However, few studies have used skin conductance (SC), though it measure's sympathetic activity, and none have measured SC on infants sitting up and actively engaged with another person, a significant challenge given the measures sensitivity to movement artifact. In this pilot/feasibility study, we present a procedure for measuring infant SC during active engagement with another person who executes a series of startling claps to elicit an SC response. We measured SC on the plantar surface of the foot of seventeen 5-month-old infants. We found unconditioned SC responses that were related to the intensity of physical startle reactions for each clap trial. We also found anticipatory, conditioned SC responses that occurred within 5 s before each clap that occurred when the researcher raised his clasped hands. These conditioned SC responses grew linearly in intensity over trials. We conclude that SC may be a useful addition to the infant researcher's armamentarium and may indeed be used to measure physiologic reactivity in infants even when actively engaged with another person. Addition of SC measurement to research on infant emotion and emotional communication is likely to advance our understanding of the psychophysiologic foundations of infant emotional development.

Predicting aggressive behavior in the third year from infant reactivity and regulation as moderated by maternal behavior

The degree to which infant attention behaviors, together with infant reactivity to frustrating events, predict aggressive behavior at 2.5 years, and the moderating effect of maternal behavior were tested with 64 low-risk mothers and infants. Mothers rated infant negative reactivity at 5 months and aggressive behavior and maternal trait anger at 2.5 years; infant and maternal behaviors were observed at 6 months. Based on hierarchical multiple regressions, infant attention to frustrating events at 6 months positively predicted aggressive behavior, whereas looking away from frustrating events was associated with less aggressive behavior for girls only. High reactivity to limits predicted aggressive behavior only when mothers encouraged infant attention to the frustrating event, suggesting that maternal behavior amplifies developmental pathways associated with infant temperament.

Separation anxiety in first-time mothers: Infant behavioral reactivity and maternal parenting self-efficacy as contributors

This short-term longitudinal study examined the contribution of infant behavioral reactivity and maternal parenting self-efficacy to first-time mothers’ (total n = 32) separation anxiety. Infants’ behavioral reactivity indexed by gaze and facial affect were observed in the conditions of routine play and maternal still face at 3 months. Mothers reported their self-perceived parenting efficacy at 3 months and separation anxiety at 6 months. Results revealed that infants’ frequent gazing at their mother, greater negative affect, and less positive affect observed during the still face, but not during the routine play, contributed to heightened maternal separation anxiety. In addition to a direct link between low maternal parenting self-efficacy and high maternal separation anxiety, maternal parenting self-efficacy buffered against the impact of infant negative reactivity on maternal separation anxiety. The role of infant reactivity and maternal self-efficacy in parenting was discussed.

Forensic Neuropathology

Forensic Neuropathology

Childbirth complications affect young infants’ behavior

The process of childbirth and its complications have been related to the newborn's condition and to development at later ages. In this study, we examine how mode of delivery and delivery complications are related to the behavior and cortisol reactivity of infants during the first 2 months. Delivery factors (i.e. mode, duration, fetal heart function, and 5-min Apgar score) were determined in 116 healthy, term, firstborn infants. The infants' behavioral and cortisol reactivity to stressors were assessed during a physical examination at 11 days and an inoculation at 2 months. Daily behavior at 6 weeks was followed by means of a four-day parental diary. Indicators of a more stressful delivery were linked to more crying/fussing in the infant and to more difficulties in regulating the infants' behavior (i.e., more unsoothability and longer crying bouts). Specific delivery complications rather than mode of delivery were linked to infants' behavior. No significant associations however, were found between childbirth and the infants' cortisol reactivity to a physical examination and an inoculation. Childbirth complications, even when mild, can apparently affect early infant behavior. These effects extend over different types of situations, and last at least until the age of 2 months, and should be taken into account in studies on infant behavior. Earlier findings of relations between childbirth complications and infant cortisol reactivity could not be replicated in this study, possibly due to the confounding effect of parity, and to the important intra-individual variability present in the infants' cortisol.

Infant Resilience to the Stress of the Still‐Face

Respiratory sinus arrhythmia (RSA) is related to infant emotion regulation and resilience. However, few studies have examined RSA of infants and mothers during a stressful experience. Even fewer studies have measured infant and mother skin conductance (SC), which in part reflects anxiety. This pilot study examined RSA, heart rate (HR), and SC patterns of 12 five-month-old infants and their mothers during normal interaction and a stressful perturbation of the interaction in which the mother does not respond to her infant-the Face-to-Face Still-Face (FFSF) paradigm. Dyads were grouped into four categories by two conditions: whether the infant protested to the Still-Face episode (SF) and whether they "recovered" from the SF by reducing protest when the mother resumed interaction in the Reunion (RE). Infants who recovered from the SF had the largest increase in RSA from SF to RE. Mothers of infants who recovered from the SF showed a decrease in RSA during the RE, suggesting mobilization of infant soothing behaviors. Mothers of infants who did not recover from the SF showed physiologic markers of anxiety in the form of continued increases in RSA and high levels of SC. Furthermore, these mothers behaved in a manner that was not responsive to their infant's disengagement cues. These pilot results demonstrate the feasibility of measuring infant SC, a measure long disregarded in infant research. The findings suggest that maternal psychophysiology may be related to infant resilience and suggest a bidirectional effect of maternal and infant reactivity.

Enterobacterial 38-kDa outer membrane protein is an age-dependent molecular marker of innate immunity and immunoglobulin deficiency as results from its reactivity with IgG and IgA antibody

In earlier studies on an animal model we observed protective properties of outer membrane proteins (OMPs) of Shigella, Hafnia, and Escherichia coli strains. In order to investigate human sera for reactivity with OMPs we subjected these proteins to immunoblotting with umbilical cord plasma and sera from children and adults. The IgG and IgA antibodies interacted primarily with a 38-kDa protein, in similar way for several enterobacterial strains, but different for Pseudomonas aeruginosa. This observation prompted us to determine the reactivity with the purified 38-kDa OMP in the sera of several groups of children. The reactivity of the protein from Shigella flexneri serotype 3a with sera in ELISA was age dependent, increasing from low reactivity in infants to the adult antibody level. The IgG and IgA antibody specific response thus revealed the normal pattern of immunity. The level of IgA and IgG antibody was significantly low in child patients with IgA and/or IgG immunoglobulin deficiencies, but was at the healthy control level in children with recurrent respiratory tract inflammation. These data correlated with total IgA and IgG levels in immunoglobulin-deficient children. The results indicate that this protein may serve as an immunodiagnostic marker, but also as an antigen carrier in vaccines.

Early predictors for adult asthma and lung function abnormalities in infants hospitalized for bronchiolitis: A prospective 18- to 20-year follow-up

In the present cohort, 85% of infants hospitalized for wheezing outgrew their symptoms until puberty, but 30-40% had asthma, depending on criteria, again in young adulthood. The aim of this study was to determine early predictors for adulthood asthma, bronchial reactivity, and lung function abnormalities in infants hospitalized for bronchiolitis. Fifty-two children hospitalized for bronchiolitis at < 2 years of age were restudied at the median age of 19 years. Wheezing histories and early risk factors for later asthma were recorded prospectively during infancy. The follow-up study consisted of a written questionnaire, physical examination, flow-volume spirometry, methacholine inhalation challenge, home peak expiratory flow monitoring, and skin-prick tests. In univariate analyses, parental asthma and repeated wheezing at age the age of 0-1 years and 0-2 years predicted adulthood asthma. Repeated wheezing at age the age of 0-1 years predicted later bronchial reactivity. Onset and recurrence of wheezing at < 1 year of age, parental atopy and asthma, and maternal smoking during infancy were related to subnormal lung function parameters. In multivariate logistic regression, adjusted for sex, age on admission, current smoking, and atopy in infancy and, currently, repeated wheezing both at < 1 year and < 2 years of age was an independent predictor for adulthood asthma. Parental asthma and repeated wheezing predict adulthood asthma in infants hospitalized for bronchiolitis, and maternal smoking predisposes them to lung function impairment in adulthood.

Ordinary Variations in Maternal Caregiving Influence Human Infants' Stress Reactivity

We sought to extend earlier work by examining whether there are ordinary variations in human maternal caregiving behavior (MCB) that are related to stress reactivity in infants. We observed 185 mother-infant dyads and used standard coding systems to identify variations in caregiving behavior. We then created two extreme groups and found that infants receiving low-quality MCB showed more fearfulness, less positive joint attention, and greater right frontal electroencephalographic asymmetry than infants receiving high-quality MCB. Group differences in stress reactivity were not a result of measured infant temperament. However, infants receiving low-quality MCB manifested significantly more negative affect during caregiving activities than did infants receiving high-quality MCB. The results suggest that ordinary variations in MCB may influence the expression of neural systems involved in stress reactivity in human infants.