Poster group
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poster
Previous research on the development of behavioral inhibition from earlynegative reactivity has usually employed a composite index of reactivityacross various modalities, including auditory, olfactory, and visualstimuli. The current study involves a sample of infants selected at 4months of age on the basis of their reactivity to auditory, olfactory, andvisual stimuli. Later laboratory assessments of behavioral inhibition tothe unfamiliar were made at 14 and 24 months of age, and cardiac data(heart period and heart period variability measures) were also gathered atthese ages. At 48 months of age, social reticence was assessed in alaboratory play session with unfamiliar peers, and cardiac data were againcollected. Parent report of behavior problems (CBCL) was also collected at48 months.Analyses showed that negative reactivity to auditory stimuli at 4 months ofage was a more consistent predictor of later behavior and physiologicalregulation than was negative reactivity to olfactory or visual stimuli at 4months. Significant positive correlations were found between negativereactivity in each modality (auditory, visual, and olfactory) at 4 monthsand an index of behavioral inhibition to the unfamiliar at 14 months ofage. However, correlations between the 4-month reactivity scores andbehavioral inhibition to a stranger at 24 months of age were significantonly for negative reactivity to auditory stimuli, and not for negativereactivity in the other two modalities or for the global negativereactivity composite. A comparable pattern was seen for correlationsbetween 4-month negative auditory reactivity and heart period variability(HPV) at 14 and 24 months. At 14 months, significant negative correlationswith HPV were found for 4-month reactivity in all modalities, but at 24months the negative reactivity-HPV correlations were significant only fornegative auditory reactivity. Negative reactivity to auditory stimuli at 4 months was also significantlycorrelated with reticence in the peer-play session at 48 months and wassignificantly negatively correlated with HPV at 48 months. There was also asignificant correlation between negative auditory reactivity andinternalizing problems on the CBCL at 48 months. Negative reactivity inthe other two modalities at 4 months or the global reactivity compositewere not significantly correlated with any of these 48-month variables.Developmental models of behavioral inhibition in late infancy and earlychildhood typically posit that some infants are biologically predisposed tohave a low threshold for arousal in limbic structures when confronted withsocial stimulation. However, hypersensitivity in earlier stages of sensoryprocessing in early infancy may also contribute to the development ofindividual differences in inhibition. Our findings suggest that earlyhypersensitivity to stimuli in the auditory modality may be especiallysalient in this respect. Such auditory hypersensitivity in infancy maymean that the infant is more easily Ôoverloaded' by auditory stimuli thatare frequently encountered in social situations in later childhood. Thismay cause a child to exhibit more restrained and inhibited behaviors andmay lead to the development of internalizing problems.
poster
Seventy-eight 2-month-olds participated in a multimeasure, 5-year study of neurophysiologicalregulation and its role in long-term childhood development and functioning. Forty-three returnedwith their mothers at 5 years. Baseline vagal tone (Vna, an index of respiratory sinus arrythmia,RSA) measured under conditions of minimal environmental demand is an indicator of theinfant's capacity to maintain physiological homeostasis and to react when challenged. At age 2-months, baseline vagal tone was derived from ECG recordings collected while the infants werequiet and alert and seated in an infant seat. Among multiple measures collected at 5 years,mothers completed the Child Behavior Questionnaire (CBQ), Preschool Behavior Questionnaire(PBQ), the Vineland Adaptive Behavior Scales, and the Family Adjustment Device (FAD). Correlational analyses were conducted to assess relations between 2-month baseline Vna andthese 5-year assessments of temperament, problem and adaptive behavior, and familyfunctioning. Infants with higher baseline Vna at 2 months were rated by their mothers on CBQscales at 5 years as less Angry and Frustrated, less Fearful, and less Sad; they showed lessDiscomfort to sensory stimulation, more Attentional Focus, greater ability to Shift Attention,more Smiling and Laughter and were more Active. Higher 2-month baseline Vna also related tolower scores on the Anxiety Scale of the PBQ and to higher scores on Vineland Scales ofCommunication, Daily Living Skills, and Adaptive Behavior Composite. Surprisingly, earlyinfancy neurophysiology also related to healthier family functioning at 5 years (higher 2 monthbaseline vagal tone related to lower FAD scores (healthy family functioning) on the ProblemSolving, Behavior Control, Role, and General Functioning subscales). Collectively, these severalindicators suggest that early neurophysiological regulation is predictive of childhoodtemperament and behavior and may be an underlying characteristic of children that contributes tooverall family functioning.
poster
Seventy-eight 2-month olds participated in a multimeasure, 5-year study of neurophysiologicalpredictors of long-term development and functioning. Forty-three returned with their mothers at5 years. Vagal reactivity (assessed as change in Vna from baseline-to-environmental challenge) isan indicator of the infant's capacity to engage and disengage vagal regulatory mechanisms thatincrease and decrease the infant's metabolic resourses to cope with environmental demand. At 2months, infant Vna reactivity was derived from ECG recordings collected prior to and during twosuccessive infant-controlled habituation procedures. Assessments at 5 years included a maternalreport of temperament (Child Behavior Questionnaire, CBQ) and laboratory measures ofperceived self-concept (Harter's Pictorial Scale of Perceived Competence and SocialAcceptance); attention, impulsivity, and motivation (Gordon Diagnostic System and BehavioralRating Scale); event knowledge (an Event Interview); and language (coded transcripts oflanguage during a mother-child interaction). Relations between 2-month vagal tone reactivityand 5-year developmental outcome measures were determined by partial correlations controllingfor baseline influences on outcome measures. Greater Vna reactivity (suppression from baselineduring habituation task) at 2 months was related to lower scores on the CBQApproach/Anticipation and Discomfort scales; higher scores of Physical Competence andMaternal Acceptance (Harter Scales); greater motivation during the GDS task; more correctresponses on GDS task; higher scores of temporal ordering (Event Interview); and more totalutterances during a mother-child interaction. These findings suggest that good neurophysiologicalregulation during environmental challenge in early infancy is an important self-regulatorymechanism that contributes to children's long-term development in multiple domains.
poster
Previous work in our laboratory has examined the relationship betweenbehavioral reactivity in infancy and its relation to vulnerability tochallenge as reflected in distress or withdrawal (behavioral inhibition)in the second year. Research suggests this characteristic may be relatedto a lower threshold of response to uncertainty in the limbic structuresof the nervous system. One mechanism for this response could be greatersympathetic tone in the autonomic nervous system (ANS). A peripheralmeasure of autonomic tone is the relative contribution of sympathetic andparasympathetic activity to heart rate. Participants were part of a longitudinal sample first classified at 4months of age as high or low reactive based on observations of behavior toa standard set of visual, auditory and olfactory stimuli. Infants wereclassified based on frequency of motor activity and amount of distressexpressed by fretting or crying. The children were then observed in thesecond year of life for behavioral inhibition. Children who had been highreactive infants were more likely to be behaviorally inhibited. In thepresent study, when the children were 10 years of age, as part of a largelaboratory battery, a baseline heart rate was obtained while the subjectswere in a supine position on paced breathing (.25Hz). Periods of heartrate data, 128 seconds in length that met criteria for stationarity, wereextracted from the time series, and analyzed with standard FFT procedures.The resulting heart rate power spectra, were divided into two components,one associated with with both parasympathetic and sympathetic activity -PSA (.01-.15 Hz), and one associated with only parasympathetic (vagal)activity - PA (.2-.4HZ). There was a significant relationship betweenbehavioral inhibition and the proportion of sympathetic/parasympatheticpower (Chi Square4.18, p.04); more children who were behaviorallyinhibited showed proportionately greater sympathetic activation. There wasno relation found between behavioral inhibition and either cardiaccomponent alone, or with mean heart rate. The results suggest thatsympathetic/parasympathetic balance measured in the cardiac signal mayindex underlying tonic activity of the ANS and help differentiatebehaviorally inhibited from uninhibited children.
poster
All infants generally exhibit some degree of fussiness between thethird and twelfth weeks of extrauterine life. Within the population,between ten and thirty-six percent exhibit extreme fussy behaviour,otherwise known as 'infant colic'. Sometimes a precipitating factor inchild maltreatment, it likely contributes to maladaptive parent-infantrelationships. Current research into paroxysmal fussy behaviour increasinglyfocuses on two possible explanations for the phenomenon. One supposesthat 'infant colic' results from over stimulation; the infant lacks theability to screen stimuli, and becomes overexcited. The other arguesthat the paroxysmal fussy infant lacks the ability to change from onebehavioural state to another, and becomes agitated when unable to makethe transition. This longitudinal study psychophysiologically compared clinicallydifferentiated groups. That is, it examined the psychophysiologicalresponses of otherwise normal and healthy paroxysmally fussy infants(n30) three to twelve weeks of age with others (n30) drawn from thesame target population who exhibited minimally fussy behaviour. Thestudy collected physiological data (heart rate and salivary cortisol)and psychological data (infant behavioural states) in the naturalenvironment. Data collection took place once during each of ten weeks.Researchers used a lightweight memory unit to collect heart rate dataover twenty-four hours, at 60-second intervals. Correspondingly,parents recorded any changes in their infants' behaviour, according tosix behavioural states. During the same twenty-four hour period,researchers collected saliva specimens three times, once in the morning,again in the afternoon and then during an episode of fussy behaviour. Descriptive and inferential analyses of data will examinedifferences between the two known groups. Analyses of the now completedstudy will include repeated analysis of variance. In addition, analyseswill investigate whether intragroup differences emerge.
poster
Maternal hypertension (HTN) in pregnancy places infants at greater risk due to utero-placental insufficiency and placental abruptions, as well as preterm birth and associated sequelae. Little is known, however, about how mothers' cardiovascular regulation may influence early interactions with their infants and, in turn, infants' development of adaptive autonomic and affective self-regulation. Biobehavioral regulation becomes particularly important during the perinatal period when mothers and infants are challenged by constantly changing physiological, endocrinological, and psychosocial environments. This study sought to examine the integration of these processes during the early postpartum period and influences on early relationship and affective development across the first 2 years. Forty-seven women and their infants of diverse ethnocultural and psychosocial backgrounds were balanced within HTN (n18) by infant health status groups (healthy fullterm [n7] and preterm infants [n14], and preterm infants with RDS and CNS disorders [n26]) and followed prospectively at 35 & 42 wks PCA, 1 & 2 yrs CGA. Prenatal, intrapartum, and neonatal medical records were reviewed to complete Hobel et al's Perinatal Risk Scales. Neonatal heart rate measures included variability (HRV) and RSA (Porges' Vna), an index of parasympathetic influences on HR and functional CNS integrity) during sleep and social interaction with (a) an examiner and (b) with their mothers. At 1 and 2 yrs, mother-infant interaction was videotaped, scored by naieve observers and Bayley Scales and Achenbach & Edelbrock's child behavior checklist were administered. Hierarchical multiple regression analyses examined the contribution of HTN beyond the influences of psychosocial risk (Sameroff et al, 1985) and other medical risks. HTN was not correlated with socioeconomic risk in this predominantly preterm sample and did not contribute significantly to birthweight, GA, total Hobel neonatal complications, HRV or RSA during sleep (baseline). However, findings ( all ps < .05) indicated HTN was associated with more extensive newborn hematologic complications (primarily sepsis). During responsive social interaction with an examiner, infants of mothers with HTN also had faster heart rates (174 vs. 155 BPM), higher rates of distress/agitation (HTN17.6 vs. 4.8%), and significantly less synchronony between RSA and behavior, suggesting a pattern of sympathetic challenge in this situation (cross-spectral coherence HTN14.8 vs. 25.3 [analogous to R2]). During mother-infant interaction, mothers with HTN had lower rates of positive affect and responsivity, and both mothers and infants had higher rates of detachment and negative affect. Maternal behavioral differences dissipated by 2 years and there were no differences in Bayley or CBCL subscores associated with HTN directly, although these infant outcomes were predicted by neonatal interaction behavior and RSA, social and medical risks. Further, infants of women with HTN continued to evidence lower rates of social initiatives and regulation, with higher rates of detachment and negative affect. Findings suggest that maternal cardiovascular dysregulation may, in turn, predispose some infants to difficulties in autonomic and affective regulation. However, the question remains whether this is due to the intergenerational transmission of some innate regulatory vulnerability or if they are a consequence of less optimal early relationship characteristics.
poster
Activity of the limbic-hypothalamic-pituitary-adrenocortical (LHPA) axis is responsive to stressful social situations. Previous research has shown that full-day, center-based child care produces a rise in cortisol, the hormone produced by the LHPA axis, over the day (Tout et al., 1997). This rising pattern contrasts with the normal circadian rhythm of the hormone which typically shows a decrease over the day. Thus far, all of the studies of daycare and cortisol levels have focused on the preschool (3 to 5 years) or older child. Significant age effects have been found, with rising cortisol over the day being noted only among the youngest (3- and 4-year old) children (Dettling, et al., 1999). The purpose of this study was to determine whether toddlers also show a rise in cortisol over the day at childcare, and whether the levels observed are similar to those noted among the 3 and 4 year old children. The previous studies of cortisol and childcare strongly suggest that the rise is associated with less mature social skills. Children with more aggressive, less well regulated behavior exhibit larger increases in cortisol from morning to afternoon at childcare. Toddler's skills for navigating the peer context are just emerging. If the challenge of social interaction with a group of peers accounts for some of the elevation in cortisol, we might expect toddlers to show similar or perhaps more dramatic elevations in cortisol over the day at childcare. In the current study, we examined cortisol levels for children (N 3D 37) in toddler classrooms (age 1 to 3) at two full-day childcare centers. The centers were rated as high quality (as measured by the ECERS). Children were sampled at 10 a.m. and 4 p.m. on 3 school days and 2 home days, and values were averaged within time and context. A repeated measures ANOVA of Time (a.m., p.m.) X Context (school, home) revealed a significant interaction between factors, F(20) 3D 13.76, p<.01. Using tests of simple effects, we determined that the mid-morning levels of cortisol did not differ from home to childcare. At home there was no change in cortisol from morning to afternoon in this age group. This finding is consistent with a previous home study of this age group (Lane, honor's thesis), which showed that the emergence of a decrease in cortisol from mid-morning to mid-afternoon appears after 3 years of age. At childcare, a marked increase in cortisol over the day averaging .17 ug/dl was noted, which was 1.5 standard scores above the mean of the afternoon home values. In Dettling et al., 1999, the afternoon childcare values for the 3- and 4-year old averaged 0.75 standard scores above their home levels. This comparison suggests that the toddlers in the present study were exhibiting even greater activation of the LHPA axis over the day at childcare than previously noted for young preschoolers. These results will be examined in relation to child behavior and temperament in order to help explicate the basis for the activation of this system in childcare settings.