Processing speed in the 1st year of life: a longitudinal study of preterm and full-term infants

Processing speed was assessed at 5, 7, and 12 months in full-term and preterm infants (birth-weight < 1,750 g). Speed was gauged directly in a new task by presenting infants with a series of paired faces, one that remained the same across trials and one that changed; trials continued until infants showed a consistent novelty preference. At all ages, preterms required about 20% more trials and 30% more time than full-terms to reach criterion. Among preterms, slower processing was associated with greater medical risk (e.g., respiratory distress syndrome). Developmental trajectories for speed (and attention) were similar for both groups. Thus, the deficits in processing speed previously found for preterms in childhood are already present in the 1st year of life.     

Dyadic and triadic skills in preterm and full term infants: a longitudinal study in the first year

This longitudinal study examined dyadic and triadic skills in 26 preterm and 31 full term infants at 3, 6 and 9 months of age. In dyadic interaction, infants engaged with a stranger in face-to-face play interrupted by a still-face episode. In triadic interaction, infants interacted with the adult stranger as she coordinated gaze between the infant and object. Both groups were sensitive for non-contingency in both dyadic and triadic interactions. There were significant group and developmental differences for dyadic and triadic competencies. Compared to full term infants, preterms made less positive elicits during the still-face at 6 months and followed gaze less at 9 months of age. Six-month dyadic skills and 9-month triadic competencies were positively related in preterm and full term infants.     

Tonic and phasic orientation in full-term and preterm infants

Thirty-three full-term infants and thirty-eight preterm infants (on average born at 30 weeks gestation) were tested for their latency to turn toward checkered stimulus patterns (phasic orienting or "attention-getting") and for the duration of their initial fixation (tonic orienting or "attention-holding"). Plotted against the logarithm of the subjects' postconceptional age, turning latency fell linearly between 36 and 120 weeks, while fixation time fell abruptly at 53 weeks. Preterm and full-term infants showed the same developmental trends, implying that both of these attentional behaviors are biologically timetabled and that neither is greatly affected by premature extrauterine experience. Unexpectedly, phasic orientation in the first 30 postnatal days was significantly faster in preterm than in full-term infants, and fixation times failed to differ. Despite the necessary functional integration of phasic and tonic orienting in mature visual scanning and attention, the present results suggest an independence in their early postnatal development and that neither is mature at birth.     

Joint attention abilities in Brazilian preterm and full-term infants

Joint attention abilities of preterm and full-term Brazilian infants were assessed at 12- and 18-months, age corrected for prematurity. Results showed that preterm infants displayed significantly lower levels of correct responses to others’ bids for joint attention at both time-points, compared to full-term infants. Both groups improved their responding to joint attention from 12 to 18 months of age. Contrastingly, prematurity did not impact infants’ initiating joint attention behaviors, which remained stable over time for both groups. Findings were discussed in terms of the specific mental processes involved in distinct behavioural dimensions of joint attention.     

Attention development in infants and preschool children born preterm: a review

A potential mechanism that can explain preterm children's heightened risk for the development of later cognitive and behavioral problems is attention. Attention is the ability of an infant or child to orient to, to shift between and to maintain focus on events, objects, tasks, and problems in the external world, processes which are all dependent on the functioning of attentional networks in the brain. The aim of this paper is to provide a review of the literature on attention development in children born preterm during the first 4 years of life. First, research examining the differences between preterm and full-term children indicates that early attention development in infants born preterm is less optimal and that these differences increase when infants grow into toddlers. Second, studies investigating individual differences within preterm populations reveal the influence of both biological factors and environmental factors. Third, individual differences in early orienting and sustained attention have been shown to be predictive of later attentional, cognitive and behavioral functioning in children born preterm. The importance of long-term follow-up studies, with a focus on individual developmental trajectories in orienting, sustained and executive attention, is emphasized.     

Attention and recollective experience in recognition memory

The functional relation between recognition memory and conscious awareness was assessed in an experiment in which undivided attention at study was compared with two divided attention conditions, one more demanding than the other. When recognizing a word from the study list, subjects indicated whether they could consciously recollect its prior occurrence or recognized it on some other basis, in the absence of conscious recollection. Divided attention at study progressively impaired word recognition accompanied by conscious recollection. Recognition in the absence of conscious recollection was not affected by divided attention. These findings are interpreted as providing further support for the idea that recognition memory entails two distinct components, one based on associative and contextual information, the other based on a "traceless" awareness of familiarity.     

Attention affects the recognition of briefly presented visual stimuli in infants: an ERP study

This study examined the effect of attention in infants on the ERP changes occurring during the recognition of briefly presented visual stimuli. Infants at ages 4.5, 6 and 7.5 months were presented with a Sesame Street movie that elicited periods of attention and inattention, and computer-generated stimuli were presented overlaid on the movie for 500 ms. One stimulus was familiar to the infants and was presented frequently, a second stimulus was familiar but presented infrequently, and a set of 14 novel stimuli were presented infrequently. An ERP component labeled the 'Nc' (Negative Central, about 450-550 ms after stimulus onset) was larger during attention than inattention and increased in magnitude over the three testing ages during attention. Late slow waves in the ERP (from 1000 to 2000 ms post-stimulus onset) consisted of a positive slow wave in response to the infrequent familiar stimulus at all three testing ages. The late slow wave in response to the infrequent novel stimulus during attention was a positive slow wave for the 4.5-month-old infants, to a positive-negative slow wave for the 6-month-old infants and a negative slow wave for the 7.5-month-old infants. These results show attention facilitates the brain response during infant recognition memory and show that developmental changes in recognition memory are closely related to changes in attention.     

Development of visuospatial short-term memory in the second half of the 1st year

Eighty 5.5- to 12.5-month-old infants participated in 4 delayed-response procedures challenging shortterm visuospatial memory (STVM), 2 that varied the time between presentation and search and 2 that varied the number of locations. Within each type of challenge, 1 task required a gaze response and 1 required a reach response. There was little improvement in STVM performance from 5.5 to 8 months and linear improvement in the percentage correct from 8 to 12 months, with overall STVM performance accounting for 66% of the variance in age. Improvement in searching multiple locations lagged behind improvement in spanning longer delays. Memory scores did not vary for the visual and manual tasks. Perseveration was greatest for reach responses, increased with challenge, and decreased with age. ((c) 2004 APA, all rights reserved)     

Families created through surrogacy arrangements: parent-child relationships in the 1st year of life

Findings are presented of a study of families created through surrogacy arrangements. Forty-two surrogacy families were compared with 51 egg-donation families and 80 natural-conception families on standardized interview and questionnaire measures of the psychological well-being of the parents, the quality of parent-child relationships, and infant temperament. The differences that were identified between the surrogacy families and the other family types indicated greater psychological well-being and adaptation to parenthood by mothers and fathers of children born through surrogacy arrangements than by the natural-conception parents.     

Attention and reaction to distress in infancy: a longitudinal study

The primary aim of this study was to verify whether early individual differences in look duration are related to general mechanisms of the infant nervous system that draw together attention and emotion. Thirty-one infants were observed at 3, 5, and 11 months of age. Facial expressions of pain and distress were observed by means of C. Izard's (1979) Maximally Discriminative Facial Movement Coding System 90 s after routine pediatric vaccinations. Several measures of visual attention were taken experimentally in a separate testing session. Significant correlations between measures of attention and duration of facial expressions of pain and distress were found at each age level. Infants who showed pain or distress for a shorter time period also paid attention for a shorter time period and vice versa. The main conclusion is that individual differences combining control of both pain and attention can be identified from early infancy.     

Early receptive and productive language skills in preterm and full-term 8-month-old infants

Early receptive and productive language skills were examined for preterm low birthweight infants and full-term normal birthweight infants from middle-class homes. Nineteen preterm infants and 19 full-term infants were observed in a laboratory setting at the gestationally corrected age of 8 months. To avoid the frequent confound between prematurity and low socioeconomic status, mothers of the two groups of infants were matched on educational levels. Regression analyses were used to assess the relative influence of infant cognitive skills, infant sociability, infant birth status, and the mothers' language input as possible predictors of infant receptive language and vocal behavior. Receptive language skills were associated with higher cognitive performance, greater sociability, and preterm birth. Productive language skills were associated with higher cognitive performance. On the basis of this research, the prognosis for language development in preterm infants raised in middle-class homes appears to be excellent.This research was aided by Social and Behavioral Sciences Research grant No. 12-11 from the March of Dimes Birth Defects Foundation and supported by DHHS Grant HD03352. Computing was provided by the Waisman Center Computing Facility at the University of Wisconsin-Madison. Donna Boylan, Sue DaPra, Maria Kleczewski, Michal Rubin, Susan Silverber, and Paula VanLaanan assisted with data collection.     

Genetic and environmental relationships between head circumference growth in the first year of life and sociocognitive development in the second year: a longitudinal twin study

Although growth in head circumference (HC) during infancy is known to predict later childhood outcomes, the mechanisms underlying this association with later sociocognitive abilities remain undetermined. Thus, using a sample of 241 pairs of normally developing Japanese twins, this study investigated the underpinnings of the association between HC growth (difference between HC at birth and at 10 months) and sociocognitive abilities at 19 months as measured by 10 items from the M-CHAT. Phenotypic correlations between HC at birth and sociocognitive abilities and between HC growth and sociocognitive abilities were marginal and not significant. However, multivariate genetic analyses using Cholesky decomposition revealed that genetic influences on HC growth and those on sociocognitive abilities were negatively associated. On the other hand, shared and nonshared environmental influences on HC growth were positively associated with influences on sociocognitive abilities. Genetic and environmental influences on HC at birth were not significantly associated with influences on sociocognitive abilities. These results help to clarify the role of brain growth during infancy in the subsequent development of sociocognitive abilities and highlight the importance of examining the different roles of genetic and environmental influences in studies of these areas.     

Hormonal sensitivity of preterm versus full-term infants to the effects of maternal depression

Comparisons were made of differences in the hormonal sensitivity of preterm versus full-term infants to maternal depression, as reflected in children's cortisol levels. In Study 1 (N=25), a comparison was made between preterm versus healthy full-term children. In Study 2 (N=80), a comparison was made between preterm infants and full-term infants with mild or moderate medical problems. Preterm infants were found to be highly reactive to maternal depression (as measured by the Beck Depression Inventory). That is, they demonstrated higher cortisol levels when paired with depressed mothers and lower cortisol levels when paired with non-depressed mothers. No equivalent effects were found for children who were full-term, even when they had experienced other medical problems at birth. It was concluded that premature infants are exceptionally sensitive to the "emotional climate" in their home environment. As a result, they may manifest very different hormonal outcomes--with implications for their later development.     

Object retrieval in the 1st year of life: learning effects of task exposure and box transparency

Before 12 months of age, infants have difficulties coordinating and sequencing their movements to retrieve an object concealed in a box. This study examined (a) whether young infants can discover effective retrieval solutions and consolidate movement coordination earlier if exposed regularly to such a task and (b) whether different environments, indexed by box transparency, would impact the rate of learning and time of discovery of these solutions. Infants (N=12) were presented with an object retrieval task every week from 6 1/2 months of age until they were able to retrieve the toy from the box using coordinated two-handed patterns for 3 weeks. To reach that criterion, infants tested with an opaque box took 2 1/2 months and infants tested with a semitransparent box took 1 1/2 months. Both groups outperformed age-matched controls who received a one-time exposure to the task. Repeated exposure to the task and vision of the toy significantly enhanced this process of solution discovery.     

Emotional and neuroendocrine regulation in very preterm and full-term infants at six months of age

Emotional and neuroendocrine regulation have been shown to be associated. However, results are inconsistent. This paper explores the functioning and relationships between these two systems in 54 healthy preterm and 25 full-term born infants at six months of age. Results showed significant differences between very preterm and full-term children in emotional intensity and regulation, as well as in neuroendocrine regulation. No evidence of an association between neuroendocrine and emotional regulations was found. Results suggest a possible delay in the maturation of the neuroendocrine system as well as in emotional regulation in very preterm infants.