Preterm outcomes research: a critical component of neonatal intensive care

While early preterm outcome studies described the lives of preterm survivors to justify the efforts required to save them, subsequent studies demonstrated their increased incidence of cerebral palsy, mental retardation, sensory impairments, minor neuromotor dysfunction, language delays, visual-perceptual disorders, learning disability and behavior problems compared to fullterm controls. Because infants born at the lower limit of viability require the most resources and have the highest incidence of neurodevelopmental disability, there is concern that resources have gone primarily to neonatal intensive care and are not available for meeting the followup, health, educational and emotional needs of these fragile infants and their families. Despite many methodological concerns, preterm outcome studies have provided insight into risk factors for and causes of CNS injury in preterm infants. Nevertheless, it remains difficult to predict neurodevelopmental outcome for individual preterm infants. Perinatal and neonatal risk factors are inadequate proxies for neurodevelopmental disability. Recent randomized controlled trials with one to five year neurodevelopmental followup have provided valuable information about perinatal and neonatal treatments. Recognizing adverse longterm neurodevelopmental effects of pharmacological doses of postnatal steroids is a sobering reminder of the need for longterm neurodevelopmental followup in all neonatal randomized controlled trials. Ongoing longterm preterm neurodevelopmental studies, analysis of changes in outcomes over time and among centers, and evaluation of the longterm safety, efficacy and effectiveness of many perinatal and neonatal management strategies and proposed neuroprotective agents are all necessary for further medical and technological advances in neonatal intensive care.     

Visual orienting and attention deficits in 5- and 10-month-old preterm infants

Cognitive outcomes for children born prematurely are well characterized, including increased risk for deficits in memory, attention, processing speed, and executive function. However, little is known about deficits that appear within the first 12 months, and how these early deficits contribute to later outcomes. To probe for functional deficits in visual attention, preterm and full-term infants were tested at 5 and 10 months with the Infant Orienting With Attention task (IOWA; Ross-Sheehy, Schneegans and Spencer, 2015). 5-month-old preterm infants showed significant deficits in orienting speed and task related error. However, 10-month-old preterm infants showed only selective deficits in spatial attention, particularly reflexive orienting responses, and responses that required some inhibition. These emergent deficits in spatial attention suggest preterm differences may be related to altered postnatal developmental trajectories. Moreover, we found no evidence of a dose-response relation between increased gestational risk and spatial attention. These results highlight the critical role of postnatal visual experience, and suggest that visual orienting may be a sensitive measure of attentional delay. Results reported here both inform current theoretical models of early perceptual/cognitive development, and future intervention efforts.     

Consistency of maternal cognitions and principles across the first five months following preterm and term deliveries

The aims of this study were to examine and compare the development of parenting cognitions and principles in mothers following preterm and term deliveries. Parenting cognitions about child development, including thinking that is restricted to single causes and single outcomes (categorical thinking) and thinking that takes into account multiple perspectives (perspectivist thinking), have been shown to relate to child outcomes. Parenting principles about using routines (structure) or infant cues (attunement) to guide daily caregiving have been shown to relate to caregiving practices. We investigated the continuity and stability of parenting cognitions and principles in the days following birth to 5 months postpartum for mothers of infants born term and preterm. All parenting cognitions were stable across time. Categorical thinking increased at a group level across time in mothers of preterm, but not term, infants. Perspectivist thinking increased at a group level for first-time mothers (regardless of birth status) and tended to be lower in mothers of preterm infants. Structure at birth did not predict later structure (and so was unstable) in mothers of preterm, but not term, infants and neither group changed in mean level across time. Attunement was consistent across time in both groups of mothers. These results indicate that prematurity has multiple, diverse effects on parenting beliefs, which may in turn influence maternal behavior and child outcomes.     

The role of chronic hypoxia in the development of neurocognitive abnormalities in preterm infants with bronchopulmonary dysplasia

Bronchopulmonary dysplasia is the most common pulmonary morbidity in preterm infants and is associated with chronic hypoxia. Animal studies have demonstrated structural, neurochemical and functional alterations due to chronic hypoxia in the developing brain. Long-term impairments in visual-motor, gross and fine motor, articulation, reading, mathematics, spatial memory and attention skills are prevalent in survivors of bronchopulmonary dysplasia, and impairments appear to correlate with the severity of hypoxia. However, due to the simultaneous occurrence of multiple neurodevelopmental risk factors, a primary or potentiating role for chronic hypoxia in these impairments has yet to be conclusively established.     

Communication in preterm infants: Why is it different?

The present paper selectively reviews the literature which compares full-term and preterm infants' communication with their mothers in the first year of life. The review is focused not only on what differences are found between full-term and preterm infants, but also why such differences exist. Particular emphasis is placed on the importance of interpreting the findings in the light of the developmental phase of the infants, the heterogeneity of the preterm population and the situation in which communication is studied. Most studies were not designed to consider these issues in any detail. Differences with respect to these factors can be found between studies, however, which may have contributed to the often contradictory findings. Consequently, comparisons between these studies provide clues about the effects of these factors on communicative development. The ultimate goal of this review is to point to important directions for future research on early communication in preterm infants.     

The role of motion in infants' perception of solid shape

Previous research has shown that infants as young as the first few months of life perceive several aspects of the three-dimensional environment. Yet we know relatively little about the visual depth information which serves as a basis for their spatial capacities. A study is reported in which a visual habituation procedure was used to examine what types of optical depth information four-month-old infants find useful in visually perceiving solid (three-dimensional) shape. Results imply that in the absence of binocular depth cues four-month-olds rely on kinetic depth information to perceive solid shape.     

The dynamics of infant visual foraging

Human infants actively forage for visual information from the moment of birth onward. Although we know a great deal about how stimulus characteristics influence looking behavior in the first few postnatal weeks, we know much less about the intrinsic dynamics of the behavior. Here we show that a simple stochastic dynamical system acts quantitatively like 4-week-old infants on a range of measures if there is hysteresis in the transitions between looking and looking away in the model system. The success of this simple three-parameter model suggests that visual foraging in the first few weeks after birth may be influenced more by noise and hysteresis in underlying neural mechanisms than by how infants process visual information after a look begins.     

Fourteen-month-olds know what others experience only in joint engagement

We investigated how 14‐month‐old infants know what others know. In two studies, an infant played with each of two objects in turn while an experimenter was present. Then the experimenter left the room, and the infant played with a third object with an assistant. The experimenter returned, faced all three objects, and said excitedly ‘Look! Can you give it to me?’ In Study 1, the experimenter experienced each of the first two toys in episodes of joint visual engagement (without manipulation) with the infant. In response to her excited request infants gave the experimenter the object she did not know, thus demonstrating that they knew which ones she knew. In Study 2, infants witnessed the experimenter jointly engage around each of the experienced toys with the assistant, from a third‐person perspective. In response to her request, infants did not give the experimenter the object she had not experienced. In combination with other studies, these results suggest that to know what others have experienced 14‐month‐old infants must do more than just perceive others perceiving something; they must engage with them actively in joint engagement.     

Regulatory competence and social communication in term and preterm infants at 12 months corrected age. Results from a randomized controlled trial

Temperamental regulatory competence and social communication in term and preterm infants at 12 months corrected age was studied in a randomized controlled intervention trial aimed at enhancing maternal sensitive responsiveness. Surviving infants <2000 g from a geographically defined area were randomized to an intervention (71) or a control group (69), and compared with term infants (74). The intervention was a modified version of the "Mother-Infant Transaction Program". Regulatory competence was measured with the Infant Behavior Questionnaire, and social communication with the Early Social Communication Scales. Preterm intervention infants with low regulatory competence had higher responding to joint attention than preterm control infants. A sensitizing intervention may moderate the association between temperament and social communication, and thus allow an alternative functional outlet for preterm infants low in regulatory competence. The finding may have implications for conceptualizations of the role of early sensitizing interventions in promoting important developmental outcomes for premature infants.     

Two- and 3-Year-Olds Know What Others Have and Have Not Heard

Recent studies have established that even infants can determine what others know based on previous visual experience. In the current study, we investigated whether 2- and 3-year-olds know what others know based on previous auditory experience. A child and an adult heard the sound of one object together, but only the child heard the sound of another (target) object. When later the sounds of both objects were played simultaneously, the adult reacted with surprise and excitement (“Oh, listen, what is that?”). In response, both 24- and 36-month-olds directed the adult's attention to the target more often than chance and more often than in a control condition in which the adult had heard neither sound. These results indicate that by 24 months of age, children's understanding of others' knowledge and ignorance is not limited to the visual domain but extends across perceptual domains.     

Cerebral palsy in very preterm infants: new epidemiological insights

The focus of this review is on new insights from recent epidemiological research on cerebral palsy in preterm infants. These include: 1) a better understanding of issues related to diagnosis and classification; 2) new information about the brain abnormalities underlying cerebral palsy in preterm infants; and 3) a better understanding of biological mechanisms that may underlie previously described epidemiological associations. Ongoing efforts to improve the diagnosis and classification of cerebral palsy have been enhanced by findings from serial examinations of cohorts of very preterm infants. Cranial ultrasonography through the anterior fontanelle of very preterm infants has provided information about grossly evident brain damage, found in about one-half of preterm infants who develop cerebral palsy. Insights into the pathophysiologic basis for certain epidemiologic associations have come from studies of experimental brain damage in animals and clinical studies of neurologic disorders in adults. Much of the current epidemiological research into the causes of cerebral palsy in preterm infants has focused on two potential mechanisms of brain damage. One mechanism involves insufficient cerebral perfusion; the other, cytokine-mediated damage, potentially triggered by events such as maternal infection (e.g., intrauterine or periodontal infection), neonatal infection (e.g., sepsis and necrotizing enterocolitis), and neonatal oxygen- or ventilator-induced lung injury. In addition to the preterm infant's increased exposure to such damaging factors, the high frequency of cerebral palsy in these infants might be due, in part, to insufficient levels of developmentally regulated protective substances, such as thyroid hormone and glucocorticoids. Models of causation currently are being investigated using recently developed methods for quantifying, with small quantities of blood, biomolecules that are suspected to either promote or protect against brain damage in the neonate. Clinical investigations now under way can be expected to identify strategies to be tested in clinical trials that could lower the risk of cerebral palsy in very preterm infants.     

Is level of prematurity a risk/plasticity factor at three years of age?

Children born preterm have poorer outcomes than children born full-term, but the caregiving environment can ameliorate some of these differences. Recent research has proposed that preterm birth may be a plasticity factor, leading to better outcomes for preterm than full-term infants in higher quality environments. This analysis uses data from two waves of an Irish study of children (at 9 months and 3 years of age, n = 11,134 children) and their caregivers (n = 11,132 mothers, n = 9998 fathers) to investigate differences in how caregiving affects social, cognitive, and motor skills between full-term, late preterm, and very preterm children. Results indicate that parental emotional distress and quality of attachment are important for child outcomes. Both being born very preterm and late preterm continue to be risk factors for poorer outcomes at 3 years of age. Only fathers’ emotional distress significantly moderated the effect of prematurity on infants’ cognitive and social outcomes—no other interactions between prematurity and environment were significant. These interactions were somewhat in line with diathesis stress, but the effect sizes were too small to provide strong support for this model. There is no evidence that preterm birth is a plasticity factor.     

Applicability and attachment findings of the Strange Situation Paradigm in infants with visual impairment

Attachment studies with diverse populations enrich the understanding of infants’ socioemotional development by documenting both universal and idiosyncratic aspects of attachment. Given the effects of attachment in children's socioemotional outcomes, such studies are necessary to investigate the impact of children's sensory impairments on attachment development. Yet, very little attachment research has focused on infants with visual impairment (VI infants), a population in which infant–caregiver emotional exchanges through visual means are reduced/absent. We investigated the applicability of the Strange Situation Paradigm (SSP), with added instructions to compensate for degraded visual input, in 20 VI infants (with no additional disabilities and who were receiving developmental counseling). In all but 1 of the SSPs coded, VI infants displayed observable attachment behavior that was classifiable. Nineteen VI infants showed attachment by 12 months of age. Across the ages tested (fractional age range = 0.9–2.33 months), most VI infants’ attachment patterns were classified as secure and organized.     

Sleep and Attachment in Preterm Infants

Infants born preterm are at elevated risk for socioemotional difficulties; however, factors contributing to this risk are largely understudied. Within the present study, we explored infant sleep as a biosocial factor that may play a role in infant socioemotional development. Within a prospective longitudinal design, we examined parent‐reported sleep patterns and observed parenting quality as predictors of infant–mother attachment in 171 infants born preterm. Using structural equation modeling, we examined main effect and moderator models linking infant sleep patterns and parenting with attachment security. Sleep patterns characterized by more daytime sleep and positive/responsive parenting predicted infant attachment security. Parent‐reported nighttime sleep patterns were unrelated to attachment in this sample of infants born preterm. These results indicate that daytime sleep and parenting quality may be important for emerging attachment relationships in infants born preterm.     

Collaborative recall and collective memory: what happens when we remember together?

Studies of collective memory have traditionally been the domain of philosophers and sociologists, while cognitive psychologists have largely investigated memory at the level of the individual. However, within cognitive psychology there is a variety of psychological theories and experimental paradigms that have been used to study the process and outcomes of remembering in groups. In this paper we review the research on group remembering and draw together findings from different traditions. In doing so, we aim to answer a series of questions about the outcomes and consequences of recalling in groups, and the particular features of groups and of memories that may be conducive to the formation of a collective memory. In clarifying what we know and what is yet to be studied about group memory, we point the way forward for a cognitive psychological study of collective memory.     

The Cost of Accessing an Object's Feature Stored in Visual Working Memory

The effects of accessing or retrieving information held in working memory are poorly understood compared to what we know about the nature of information storage in this limited-capacity memory system. Previous studies of object-based attention have often relied upon memory-demanding tasks, and this work could indicate that accessing a piece of information in visual working memory may have deleterious effects upon the other representations being maintained. In the present study, we tested the hypothesis that accessing a feature of an object represented in visual working memory degrades the representations of the other stored objects' features. Our findings support this hypothesis and point to important new questions about the nature of effects resulting from accessing information stored in visual working memory.     

Visual attention skills of premature infants with and without intraventricular hemorrhage

The relation between two medical complications associated with prematurity (intraventricular hemorrhage (IVH) and respiratory distress syndrome (RDS)) and visual attention skills of very low birth-weight (VLBW) infants were examined. Fourteen preterm VLBW infants with IVH and RDS, 9 preterms with RDS and no IVH, and 10 full-term infants matched on SES, sex, and race were assessed at 7 months of age (after correction for prematurity) for their ability to show a decremental response to a familiar visual stimulus and an increment in response to a novel visual stimulus. Measures of attention getting (turning toward a stimulus) and attention holding (sustained fixation on the stimulus after turning) were taken. On the attention-getting measures, IVH-RDS preterms had longer latencies than both the RDS-no-IVH preterm group and the full-term group. There were no group differences on attention-holding measures. The three groups did not differ in habituation to the familiar visual stimulus or discrimination of the novel stimulus. This study indicates that the early visual attention skills of preterm infants are differentially affected by specific types of prenatal complications.     

Cumulative psychosocial and medical risk as predictors of early infant development and parenting stress in an African-American preterm sample

The present study examined predictive linkages between cumulative psychosocial and medical risk, assessed neonatally, and infant development and parenting stress at 4 months of infant corrected age. Predominantly low-income, African-American mothers and their preterm infants served as participants. Cumulative psychosocial risk predicted early mental, but not motor development, while cumulative medical risk predicted both mental and motor development. Cumulative psychosocial risk, but not medical risk, predicted parenting stress. Few studies of preterm infants have reported links between cumulative psychosocial risk and infant development at such an early age, nor has earlier work found associations between cumulative psychosocial risk and mothers' perceptions of parenting. Results support the premise that early intervention should target both the medical and psychosocial needs of low-income families with preterm infants, and that addressing psychosocial stressors shortly after birth may improve developmental outcomes in infancy.     

Why don't they just let it go?

Discrepancies between what children expect about physical causality (indexed by looking time) and how they act on that knowledge have led to criticisms of claims about what infants "know." Baillargeon [Baillargeon, R. (1999). Young infants' expectations about hidden objects: A reply to three challenges. Developmental Science, 2, 115-163] advocates examining more tasks before revising views of early cognitive development. We report another discrepancy which suggests an additional indicator of what is salient for preverbal infants. While examining the Uzgiris-Hunt test performances of 40 children (26 females), 7.6-26.9-months-old, infants appeared captivated by the bouncing of a small rubber ball. However, most infants reproduced the motion of the bounce event itself, repeatedly hitting the ball against the table, rather than the experimenter's action (dropping). Comparing performances of those who did and did not imitate the drop, two possibly interrelated interpretations remained consistent with the data: infants perform goal-directed imitation of interesting phenomena, perhaps because they believe they must apply force to make them happen.     

Visual control of hand action

Recent investigations in normal and brain-damaged individuals have begun to identify the types of visual information used to plan and guide reaches. Binocular visual cues have been shown to be important for both movement planning and on-line guidance of hand movements, while emerging evidence suggests that dynamic visual analysis of the moving limb may provide a rich source of information for precise control of the hand in flight. Reaching movements appear to be planned to follow what is perceived to be a straight trajectory in peripersonal space. Furthermore, the process of selecting visual targets appears to influence hand trajectories, with hand movements curving away from non-target objects. This behaviour may be explained most effectively by a dynamic representation of space which is sculpted by attentional mechanisms into selected (target) and inhibited (non-target) regions. The role of attention in movement planning in individuals with attentional disorders is controversial. Patients with visual neglect have impairments of visuomotor control including reaches that, under certain conditions, are significantly more curved than those of normal individuals. The representations of space that neglect patients use to plan reaches may be distorted by impairments in the mechanisms that normally act to select target regions and inhibit non-target zones.