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poster
Recent work has shown early olfactory abilities in full-term newborns.Little is known, however, about olfaction in preterm newborns. This studywas aimed to observe learning abilities in relation to olfactory stimuli inpremature newborns while they were still in the Neonatal Intensive CareUnit (NICU). Two groups of healthy preterm newborns (N 3D 20), born between28 and 34 weeks gestational age and aged between 10 and 15 days, werefamiliarized 10 times with either a vanilla or an anise odor of similarintensity. A Qtip which had previously been wet with one of the odors wasslowly moved in front of the baby's nose for 10 seconds. A 20 spost-stimulation period followed. For the first group (experimental), a newodor was presented 3 times after the 10th presentation. For the secondgroup (control), the same odor as during familiarization was presented 3more times. In each group, half the infants were familiarized with vanillaand half with anise. Infants were tested while asleep in their incubator.Heart rate, facial expressions and head movements were recorded before,during, and after presentation of the olfactory stimuli. Heart rate, facial expressions, and movements went up significantlyfrom stimulation to post-stimulation indicating a reaction of arousalfollowing odor presentation. No significant change in cardiac andbehavioral reactivity was found across trials as would have been expectedif infants had habituated. Cardiac reactivity was significantly different,however, for the experimental and control groups between trials 10 and 11(change trial). Heart rate for the experimental group increasedsignificantly between trials 10 and 11, whereas it remained stable for thecontrol group. Facial expressions and movements were also significantlymore frequent in the experimental group compared to the control group onthe 11th trial. These results show premature newborns' responsivity to olfactorystimuli demonstrated by a post-stimulation increase in autonomic andbehavioral reactivity. Moreover, the difference between the two groups onthe change trials suggests that the experimental group discriminatedbetween the two odors and increased its reactivity when the new odor waspresented. Cardiac and behavioral reactivity were not significantlycorrelated across trials although they separately indicated infants'responsiveness to the olfactory stimuli. Both the increase in reactivityafter presentation of the odors and the differences between the two groupsindicate premature newborns' ability to be responsive to their olfactoryenvironment. The absence of significant change across trials on thedifferent measures could indicate a difficulty for premature newborns tohabituate to repeated olfactory stimulations as it has been shown in othermodalities for this population. However, numerous studies have shownfull-term newborns' ability to habituate to various stimuli includingodors. Given these results, we will discuss methodological and theoreticalconsiderations about discrimination and learning in preterm newborns. Thispreliminary study will also lead to more general issues on pretermnewborns' care while in the NICU.
poster
BACKGROUND: Extremely Early Born (EEB) preterm infants (gestational age < 27 weeks) are the most compromised of preterm infants requiring extensive stays in the Newborn Intensive Care Unit (NICU). Once respiratory stability is established, it is the successful attainment of nutritive sucking competence that appears to be the primary determinant of discharge readiness. Yet, nutritive sucking, which is the sophisticated integration of sucking, swallowing and breathing with behavioral state, is one of the most highly organized behaviors of the young infant. Alertness has previously been correlated with more successful feeding in full-term and well preterm infants. No previous research in this area exists specifically with EEB preterm infants. Thus, understanding how maturation of alertness in EEB preterm infants is organized in relationship to feeding appears essential to professionals preparing these infants for discharge from the NICU. OBJECTIVE: To investigate the maturation of alertness and its the relationship between and the acquisition of nutritive sucking in EEB preterm infants during the transition to nipple feeding.CONCEPTUAL FRAMEWORK: Alertness requires maturation and integration of behavioral organization. The Synactive Theory of Development provides the framework for this integration and articulates how the maturing infant organizes his/her behavior and negotiates input from the environment while coping with internal physiologic demands and maintaining homeostasis.METHOD: In a non-experimental repeated measures design, 52 EEB preterm infants were recruited with informed consent from parents using a sample of convenience. This research was conducted with a sub-sample of infants also participating in a larger NIH-NINR study. Infant behavioral state was observed weekly for 15 minutes prior to caregiving for five weeks. Once feeding was initiated, infants were observed at three intervals while in the NICU with a nutritive sucking protocol. State was collected using the Anderson Behavioral State Scale. Indicators of nutritive sucking competence were collected continuously with the Krons Nutritive Sucking Apparatus.RESULTS: Maturation of alertness over time was not significant however, frequency and duration of alertness was noted to increase across the data collection points, while indicators of nutritive sucking competence clearly, demonstrated significant maturational changes over time. ANOVA revealed a significant effect of robustness of alertness during feeding on mean number of sucks (p0.044), mean number of bursts(p0.006), and the mean number of sucks per bursts (p0.001). There were no significant effects of robustness of alertness prior to feeding on indicators of nutritive sucking competence. However, two variables were approaching significance, mean number of sucks (p0.056), and mean number of sucks per bursts (p0.071)and these effects have clinical significance. Thus, alertness prior to and during feeding appeared to increase feeding competence.CONCLUSIONS: Maturation of behavioral organization with increasing alertness although not statistically significant, has much clinical significance. This research provided increased understanding of the presentation of alertness in EEB infants, and how alertness matures and become more robust, as well as changes over time. Certainly, information about the relationship between alertness and nutritive sucking is pivotal to the practitioners' decision-making and will facilitate the initiation and successful acquisition of feeding for these infants. Facilitation of alertness prior to and during feeding with EEB preterm infants needs to be further explored.
poster
In addition to the biological hazards of the untimely requirement of adaptation to the extra-uterine life the interaction of unprepared and stressed mothers with their immature babies may involve further risks. The present study aims to contribute data to our understanding of the beginnings of mother - infant relationship by comparing preterm and full-term newborn babies` and mothers` behaviours in dyadic situation. Thirty-five preterm and 40 full-term babies and their mothers participated in the study. The preterm infants were born at 29-32 weeks of gestation, weighing less than 2000 grams, and had no severe perinatal complications. The comparison group consisted of healthy full-term neonates. The dyads were observed for approximately 10 minutes in a situation with no caregiving tasks. The mothers were not given any specific instruction. The interactional situations were videotaped. Events were coded using rating scales of maternal and infant behaviours and measures of synchrony. Factor analyses of the single item scores yielded 5 maternal and 3 baby factors. Mothers of full-term infants were verbally more active and made more efforts to maintain eye contact. Full-term babies were somewhat more alert and responsive, while the preterms displayed less discomfort. Distinct patterns of correlations between maternal and infant measures emerged in function of the babies` birth status.
poster
Executive function includes working memory, problem solving and inhibition. These abilities begin to emerge in infancy and continue to develop throughout childhood. This may be the result of maturation of the frontal cortex or of learning through interaction with the environment, or a combination of the two. The relative contributions of these two factors can be explored by comparing the performance of preterm and full term infants of the same corrected and chronological age. Executive dysfunction is believed to underlie some learning problems that emerge in middle childhood. Preterm infants are at greatly increased risk for learning difficulties in their school years. Therefore it might be predicted that they would show poorer performance on measures of executive function in infancy than term infants of the same corrected age, and that these measures might ultimately be useful in the early identification of infants at risk for learning disabilities. This study aims to compare executive function in preterm and full term infants at both the same corrected and chronological age. Subjects: Preterm (PT) infants: 36 extremely low birth weight infants (gestation weeks are less than 30 weeks) without known neurological impairment. Full Term (FT) infants: 72 healthy term infants matched with preterm infants for gender, socio-economic status and expected date of delivery.Tasks: 1) A planning task requiring 2, 3, 4, 5 or 6 moves to retrieve a toy was designed. (Based on the work of Williatts, 1998.)2) A working memory and inhibition task based on the AB task with increasing periods of delay from 2 to 10 seconds between hiding the object and retrieval. (based on the works of Diamond, 1990.)3) A sustained attention task. (Based on the work of Ruff, 1994)4) The Bayley Scales of Infant Development. (in order to partial out effects due to differences in cognitive functioning of the two groups).Procedure: The tasks were administered to both PT and FT infants at 8 months after expected date of delivery and again to term infants when they reached the same chronological age as they matched preterm infant, that is, approximately 11 months of age.Results:Preliminary results indicate that the performance of PT infants is inferior to that of FT infants on executive function and sustained attention tasks at 8 months corrected age despite comparable performances on the Bayley Scales of Infant Development. There are no significant differences in infant temperament, maternal psychological status, and family social-economic status between PT and FT infants, which may confound the result of executive function in PT and FT infants. This indicates that the maturational development of frontal lobe is responsible for the development of executive function. The inferior performance of PT infants in executive function comparing to FT infants suggests that the development of the vulnerable prefrontal cortex has been adversely affected by detrimental neonatal experiences. The deficits in executive function which are observed in PT infant may also provide indicators of long-term learning difficulties.
poster
Giving birth to a very or extremely low birth weight preterm infant isreported by parents as a traumatic experience. They struggle with feelingsof guilt, anger and depression; they feel overwhelmed and they need todevelop strategies to cope with the birth crisis. Even though many NeonatalIntensive Care Units - NICU has a 24 hours visiting policy, the neonatalstaff has observed that parents do not feel confident to take care of afragile and small infant after discharge from hospital. The need for a morecomprehensive care of high-risk infants extends well beyond their stay inNICU.With the intent of improving parental confidence in taking care of theirinfant, the Neonatal Unit staff advises parents to stay overnight togetherwith their infants in a private room at the maternity hospital, the day(s)before discharge - that is what is called Late Rooming-In (LRI). This way,they can spend one or more days practicing taking care of their infant, withsupport of the maternity multidisciplinary staff. The staff comes into theroom whenever requested.An informal analysis show that parents are more involved with this process,that they enjoy taking care of their infant by themselves, and that theyreport feelings that the infant really belongs to them.The purposes of this study are: a) to examine parental anxiety anddepression after delivery preterm infant, and before the infant dischargefrom hospital, using two different Anxiety and Depression Scales, and b) toobserve parents while taking care of their infants at the LRI usingcategories of parental responses by videotape recordings; c) using NICUNetwork Neurobehavioral Scale - NNNS, Lester & Tronick, (1994) forassessment.The participants were the parents and their preterm infants with mean GA <33 weeks at birth and mean birth weight < 1700gr..These findings suggest that parents have higher involvement in caring fortheir infant at LRI than in previous situations. Parents that stay more than24 hours at LRI are those that request the assistance of the nurse moretimes.
poster
Introduction: Research interest has focused on the differential effects ofearly biologic risk and environmental factors on the development of preterminfants, particularly of maternal-infant interactions. Preterm infantsdiffer developmentally from full term infants and posses behavioralcharacteristics that may cause them to be poorer partners in dyadicinteractions, while mothers of preterm infants have been shown to differfrom mothers of full term infants in their own interactions as well as intheir psychological status, with higher levels of depression and anxiety.The present study evaluated the association of severity of medical risk andprematurity and maternal psychological distress with quality ofmaternal-infant interactions during the feeding. Subjects: We followed 329high risk infants (122 very low birthweight (VLBW) with bronchopulmonarydysplasia (BPD), 84 low risk VLBW without BPD, and 123 term, healthy infantsfrom birth to 3 years. Groups did not differ in race, gender, or socialclass but did in gestational age, birthweight, and medical risk. Mothersand infants were seen neonatally and at follow-up visits at 8 and 12 monthsof age. At each visit, mothers completed the Brief Symptom Inventory, astandardized self-report of severity of psychiatric symptoms, which yieldsan overall measure of distress symptoms (GSI). Feeding interactions wereassessed with the Nursing Child Assessment Feeding Scale (NCAFS). Motherswere rated for sensitivity to cues, response to distress, socioemotionalgrowth fostering and cognitive growth fostering. Infants were rated fortheir responsivity and clarity of cues. Data Analyses: Linear mixed modellongitudinal analyses with GSI as a time dependent covariate were used toassess the differences among groups in interactions over time and to assessthe relationship of concurrent maternal distress symptoms to interactions.Results: All infants increased in clarity of cues and responsivity overtime (p's < .0001). Groups differed in infant behaviors over the firstyear of life (p < .05) with poorer responsivity and clarity of cues forhigh risk preterm compared to term infants, and a significant interaction (p < .009) effect for responsivity indicating that, by one year, term infantswere more responsive compared to both preterm groups. There were nosignificant group age effects on maternal responsivity to distress, and allmothers demonstrated decreased sensitivity to infant cues over time. Therewas a significant interaction effect for the social-emotional domain (p <.01) indicating, in the neonatal period, that mothers of both preterm groupsdemonstrated more socioemotional growth fostering than mothers of terminfants, but by 8 and 12 months there were no group differences. In theneonatal period, mothers of high risk VLBW infants showed greater cognitivegrowth fostering compared to mothers of term infants, but by one year,mothers of both preterm groups had lower levels than mothers of terminfants. Higher maternal psychological distress was related to lesscognitive growth fostering and decreased responsiveness to distress.Conclusion: Infant prematurity and medical risk and maternal psychologicaldistress both adversely affect maternal-infant interactions during the firstyear of life. As higher levels of maternal distress symptoms have beenidentified in mothers of preterm infants, such symptoms should be targetedfor intervention.
poster
Interest in the neonate's behaviour has increased with improvedknowledge in the
poster
Objective: To investigate the utility of infant informationprocessing measures in relation to neurodevelopmental assessmentsadministered at 8 months adjusted age in a follow-up clinic forinfants born at risk due to very low birthweight.Method: One hundred and five preterm infants, with a meangestational age of 27.8 weeks (SD 2.4) and mean birthweight of987.5 grams (SD 228.9) participated. One hundred fifty fourfull term infants were recruited as a comparison group. Theinformation processing measures included the Fagan Test of InfantIntelligence (FTII), a test of visual recognition memory, theDunst adaptation of the Uzgiris-Hunt Object Permanence Scale(OP), and a measure of Cross Modal Transfer (CMT). They wereadministered to infants at approximately 8 months of age(adjusted for prematurity as appropriate). The Bayley Scales ofInfant Development, Second Edition, Mental Development Index(MDI), the Bayley Infant Neurodevelopmental Screener (BINS) andthe Amiel-Tison Neurologic Exam (AT) were used as theneurodevelopmental outcome measures.Results: Chi-squared analysis revealed an association between OPand MDI normal versus delayed categories (p < .05). A significantassociation was found between the FTII and BINS risk categories(p < .05). Similarly, there was a trend toward a significantassociation between the FTII and the AT risk categories (p <.10). No association was found between either the FTII or CMT andthe MDI. Further, no association was found between either the OPor CMT measures and the BINS or the AT. A MANOVA showed asignificant difference between preterm and full-term groups (p <.01) on the information processing measures. Follow-up univariateanalyses revealed significant group differences only on OP (p <.001) with the preterm group scoring significantly lower than thefull term group. Drop-out rates were significantly differentbetween groups on the CMT task, with only 60.7% of the pretermscompleting the task compared to 82.3% of full term infants(p<.001). Examiners reported that the preterm infants resistedconfinement of their hand for the familiarization component ofthe CMT task.Conclusions: Mixed evidence emerges to support the use ofinformation processing measures in high risk infant follow-up. OPis associated with the MDI and discriminates between preterm andfull term groups. The FTII is not associated with the MDI, acognitively based assessment, but appears to be associated withmore neurologically based assessments (i.e., BINS, AT); however,it does not discriminate between groups. CMT is not associatedwith any of the outcome measures and does not differ betweengroups. Task characteristics of the CMT may also be problematicwhen used in a clinical setting. For the FTII, subject loss maybe a concern in follow up clinics because of the narrow windowsof assessment ages. It may not always be possible to schedulepreterm infants within the required time frame because of theirfrequent illnesses or because of clinic booking constraints.
poster
Prematurity is associated with poorer attention and increased incidence of attention disorders. While premature children born very early and at extremely low birthweights are at greatest risk, those with later gestational ages, heavier birthweights and no obvious neurologic complications also exhibit difficulties on attention tasks. Premature birth increases the risk of hypothyroxinemia (low thyroid hormone levels) because the intrauterine supply of thyroid hormones (TH) from the mother is severed before the infant's thyroid is fully functional. Previous studies have shown that transient hypothyroxinemia in premature infants contributes to poorer psychomotor development and lower intelligence. An extensive literature exists showing that TH is critically important hormone for neurodevelopment and in particular the development of the neural structures underlying attention. Numerous studies have also shown relationships between TH levels and attentional functioning in children and adults with TH abnormalities. Preliminary findings from our lab indicate that attention is poorer in infants with various thyroid deficiencies (Mirabella et al 1999). We now asked whether poor attention in infancy is also related to hypothyroxinemia of prematurity. In this ongoing study, we are recruiting infants without neurological complications of prematurity or neonatal illness and are obtaining blood samples from them at 2weeks of life and expected term. These are then analyzed for levels of TH. Preterm infants and controls are tested at regular intervals in infancy using computer-driven attention tests. This paper describes our findings on 6 month olds who were videotaped while watching the Visual Expectation Task (VExP, Haith & McCarty, 1990) and 18 month olds videotaped during the Early Childhood Vigilance Task (ECVT, Zelinsky et al, 1996). VexP shows a sequence of lively figures, which are initially shown randomly on either side of the computer screen and then alternate from side to side. The task is scored on a frame-by-frame basis for indices of looking and anticipation. ECVT presents 18 dancing cartoon figures in 3 blocks that appear suddenly and move in either direction across the computer screen. This task is scored in terms of time looking at stimuli, at screen between stimuli, and away from screen. The results indicated preterm infants had normal TH levels at 2-weeks of life, which decreased significantly by projected term. On the VExP, preliminary results on 20 preterm and 42 full-term controls show premature infants made fewer looks initially, were less able to learn the anticipatory sequence and slower at anticipating, and had more variable RTs than controls. Preterm infants' looking behaviours and RTs were significantly correlated with TH levels at expec ted term but not 2 weeks of life. On the ECVT, preliminary results on 13 preterm and 31 controls show the preterm group looked significantly less at the screen during presentation of stimuli and between stimuli. The groups did not differ in looks away from the screen. Total looks at stimuli correlated with 2-week TH values.These results show that TH depletion does occur in preterm infants after birth and this is associated with significantly poorer attention at 2 time periods in infancy.
poster
Insufficient levels of thyroid hormone (TH) during pregnancy place a developing fetus at risk for neurocognitive impairment. These insufficiencies can arise from abnormal maternal or fetal production of TH. During the first and second trimesters, when the mother is entirely responsible for the fetal TH supply, maternal hypothyroidism can reduce fetal TH. During the third, when the fetal thyroid gland is developed but not fully functional, both maternal and fetal conditions can affect fetal TH economy. The specific deficits in children who are TH deprived during pregnancy include lower IQ, and poorer memory, attention, and visuospatial abilities. This poster presents preliminary data assessing the performance of different TH-deficient groups using the Visual Expectation Task (VExP) at 6 months of age. Specifically, it tests whether the source and timing of the TH deprivation produces a particular subset of neurocognitive deficits on the VExP. Thus, each group may have its own 'behavioural signature' describing its particular subset of deficits. Four groups of infants reflecting the differing sources and timing of TH deprivation were assessed: Infants whose mothers were hypothyroid during early pregnancy, and although subsequently treated, experienced a time period early in pregnancy when TH levels were low; infants whose mothers were treated for hyperthyroidism with antithyroid medication, which crosses the placenta and reduces otherwise normal fetal TH production; infants with congenital hypothyroidism who have an absent or dysfunctional thyroid gland, and so produce little or no TH of their own until they begin treatment in the first month of life; and infants born prematurely, where maternal TH contribution is cut short by early birth.The performance of the TH-deficient groups was compared to normal controls on the VExP, which in previous research has differentiated infants exposed to alcohol and cocaine in utero from unexposed infants. This task measures infants' ability to form visual expectations to upcoming events, as well as attention and rates of visual information processing. Seven measures were derived: proportion of anticipations, proportion of fast responses, proportion of slow responses, proportion of total responses, response latency, standard deviation of response latency, response latency of anticipations. Preliminary results suggest that each TH-deficient group has a unique behavioural signature: Compared to controls, infants of hyperthyroid mothers initially showed slower latencies but manifested a pattern of hypervigilance in later trials. Infants with congenital hypothyroidism showed longer response and anticipatory response latencies, suggesting a general slowing of information processing. Finally, premature infants showed faster response latencies and a higher proportion of fast responses during postbaseline trials, but slower anticipatory latencies and fewer anticipations. Among infants of hypothyroid mothers, no deficits were found on any VExP measures. These results suggest that the source and timing of TH deprivation during the third trimester may be profiled by a unique behavioural signature, and may predicate specific behavioural impairments. We will subsequently examine associated factors which may contribute to these distinct behavioural signatures.