Cognitive function in preterm infants: no simple answers

Caesarean section and neonatal survival and neurodevelopmental impairments in preterm singleton neonates

Introduction

Evidence is lacking regarding the benefit of caesarean section (CS) for long-term neurodevelopmental outcomes in singleton preterm neonates. Therefore, uncertainty remains regarding obstetrical best practice in the delivery of premature neonates.

Objective

Our objective was to determine the association between the mode of delivery and neurodevelopmental outcomes in preterm singleton neonates who were delivered by vaginal route (VR), CS with labour (CS-L), or CS without labour (CS-NL).

Methods

Singleton neonates of less than 29 weeks' gestation born January 1995 through December 2010 and admitted to our NICU and then assessed at neonatal follow-up clinic were studied. The primary outcome was neurodevelopmental impairment (NDI) defined as cerebral palsy, cognitive delay, major or minor visual impairment, or hearing impairment or deafness at 36 months' corrected age.

Results

In this retrospective cohort study of 1,452 neonates, 1,000 were eligible for the study and 881 (88.1%) were available for follow-up. There was no significant difference in mortality between VR group, CS-L group, and CS-NL group. At 3 years, there was no significant difference between the three groups in terms of NDI. The odds of composite outcome of mortality or NDI for neonates born via CS-NL versus VR, and CS-L versus VR were 0.90 (95% confidence interval [CI]: 0.59 to 1.37) and 1.08 (95% CI: 0.72 to 1.61), respectively. Propensity score-based matched-pair analyses did not show a significant association between the composite outcome and CS with or without labour.

Conclusions

CS was not associated with increased survival or decreased risk of NDI in premature singleton neonates born at less than 29 weeks' gestation.

Executive Function and Academic Outcomes in Children Who Were Extremely Preterm

OBJECTIVES

Cognitive and behavioral impairments of children born extremely preterm (EP) (<28 weeks' gestation) and extremely low birth weight (ELBW) (<1000 g) may change with age. We assessed the individual stability of behavioral executive function (EF) from 8 to 18 years of age in children born EP or ELBW and their academic outcomes.

METHODS

Participants comprised 180 children born EP or ELBW from a large geographic cohort. We investigated the frequency of 4 developmental groups (persistent, remitting, late-onset, and typical development) on the basis of dichotomized scores (typical versus elevated) at ages 8 and 18 years in 2 indices (the Behavioral Regulation Index [BRI] and the Metacognition Index [MCI]) of the parental form of the Behavior Rating Inventory of Executive Function. Adolescent academic outcomes were measured by using the word reading, spelling, and math computation subtests of the Wide Range Achievement Test, Fourth Edition.

RESULTS

Most participants had a typical EF (BRI 61%, MCI 53%), followed by persistent (BRI 15%, MCI 16%), late-onset (BRI 12%, MCI 19%), or remitting (BRI 12%, MCI 13%) executive difficulties. Groups with executive impairments at age 18 years (persistent and late onset) had poorer academic outcomes than the typical and remitting groups. Shifting impairment categories between 8 and 18 years old was relevant to later academic outcomes.

CONCLUSIONS

Most children showed stable and age-appropriate EF, although persistent and transient difficulties were observed and related to uneven academic outcomes. Studying the origins and consequences of the developmental stability of EF may contribute to the development of interventions to decrease the adverse neurodevelopmental outcomes of preterm birth.

Cognitive Development Trajectories of Very Preterm and Typically Developing Children

Cognitive impairment is common among children born very preterm (VPT), yet little is known about how this risk changes over time. To examine this issue, a regional cohort of 110 VPT (≤ 32 weeks gestation) and 113 full-term (FT) born children was prospectively assessed at ages 4, 6, 9, and 12 years using the Wechsler Preschool and Primary Scale of Intelligence-Revised and then Wechsler Intelligence Scale for Children, 4th ed. At all ages, VPT children obtained lower scores than their FT born peers (p < .001). Growth curve modeling revealed stable cognitive trajectories across both groups. Neonatal white matter abnormalities and family socioeconomic adversity additively predicted cognitive risk. Despite some intraindividual variability, cognitive functioning of typically developing and high-risk VPT children was stable and influenced by early neurological development and family rearing context.

Social skills and developmental delay: importance in predicting the auditory and speech outcomes after cochlear implantation in children

CONCLUSION

Preoperative evaluation of social interaction and global development levels using the Vineland Social Maturity Scale (VSMS) and Bayley Scales of Infant Development-2nd edition (BSID-II) may be beneficial in predicting the postoperative outcome in pediatric cochlear implant recipients. In particular, cautious preoperative counseling regarding the poor postoperative prognosis may be necessary in children with low social skills and developmental status.

OBJECTIVE

To determine the clinical benefit of preoperative evaluation of social interaction and global development levels using VSMS and BSID-II in predicting the postoperative outcome in pediatric cochlear implant recipients.

PATIENTS

A total of 65 deaf children who underwent cochlear implantation (CI) were included in this study. Age at the time of implantation ranged from 12 to 76 months. All of the children underwent a comprehensive preimplant psychological assessment by a clinical psychologist. The VSMS and BSID-II were used for evaluating social skills and a child's development preoperatively. A social quotient (SQ) was calculated by using the VSMS for each subject using the following formula: (social age/chronological age) × 100. The auditory perception and speech production abilities were evaluated using the Categories of Auditory Performance (CAP) scale and the Korean version of the Ling's stage (K-Ling), respectively, at 1 year after CI. The associations between the preoperative SQ/developmental levels and the postoperative auditory/speech outcomes were evaluated.

RESULTS

The mean SQ was significantly decreased in the enrolled children (90.6 ± 26.1). The improvement in CAP score at 1 year after CI was correlated with preoperative SQ. The improvements in phonemic and phonologic levels of K-Ling were correlated with preoperative VSMS and BSID-II scores.

Development and validation of a parent-report measure for detection of cognitive delay in infancy

AIM

To develop a brief, parent-completed instrument (ERIC - Early Report by Infant Caregivers) for detection of cognitive delay in 10- to 24-month-olds born preterm, or of low birthweight, or with perinatal complications, and to establish ERIC's diagnostic properties.

METHOD

Scores for ERIC were collected from the parents of 317 children meeting ≥inclusion criterion (birthweight <1500 g, gestational age <34 completed weeks, 5 min Apgar score <7, or presence of hypoxic-ischaemic encephalopathy) and no exclusion criteria. Children were assessed using a criterion score of below 80 on the Bayley Scales of Infant and Toddler Development-III cognitive scale. Items were retained according to their individual associations with delay. Sensitivity, specificity, and positive and negative predictive values were estimated and a truncated ERIC was developed for use in children <14 months old.

RESULTS

ERIC correctly detected developmental delay in 17 out of 18 children in the sample, with 94.4% sensitivity, 76.9% specificity, 19.8% positive predictive value, 99.6% negative predictive value, 4.09 likelihood ratio positive, and 0.07 likelihood ratio negative.

INTERPRETATION

ERIC has potential value as a quickly administered diagnostic instrument for the absence of early cognitive delay in 10- to 24-month-old preterm infants and as a screen for cognitive delay.

Neurodevelopmental outcomes of infants born prematurely

Long-term follow-up of infants born prematurely is necessary to determine neurodevelopmental outcomes, particularly with the expansion of interest from major disabilities to high prevalence/low severity dysfunctions. Models of pathogenesis include changes due to developmental disruptions and to injury, the magnitude and type of change influenced by the infant's age, and central nervous system recovery and reorganization. Alterations in neurogenesis, migration, myelination, cell death, and synaptogenesis occur even in the absence of insult. Despite increased knowledge regarding these processes, the functional significance of brain abnormalities is unclear. Because of methodologic problems in follow-up studies, it is difficult to characterize outcome definitively. Nonetheless, an acceptable degree of agreement across studies is found with regard to specific neurodevelopmental outcomes: motor/neurologic function, visuomotor integrative skills, IQ, academic achievement, language, executive function, and attention-deficit hyperactivity disorder/behavioral issues. In general, children born prematurely have more problems in these areas than do their normal birth weight counterparts. Suggestions for improved analyses and clarification of outcomes include use of cluster analysis, structural equation modeling, growth curve analysis, developmental epidemiologic approaches, and better control of background variables using risk indexes and factor scores. Better assessment techniques measuring functions documented to be at higher risk of problems are discussed.

Long-term neurobiological consequences of early postnatal hCMV-infection in former preterms: a functional MRI study

Early postnatal infection with human cytomegalovirus (hCMV) may contribute to an adverse cognitive outcome in early preterm-born children (PT). We here set out to explore whether long-term neurobiological consequences of such an infection are detectable using fMRI in children and adolescents who were born very preterm and who either did (PThCMV+ ) or did not (PT(hCMV-)) suffer from an early postnatal hCMV-infection, when compared with typically developing healthy control (HC) subjects. Overall, data from 71 children and adolescents could be included, 34 PT (of which 15 were PT(hCMV+) and 19 were PT(hCMV-)) and 37 HC. Using a recently established "dual use" fMRI task, we investigated language and visuospatial functions. There were significant activation differences in the left hippocampus (PT > HC and PT(hCMV+) > HC), and in the right anterior cingulate cortex (PT(hCMV-) > PT(hCMV+)) when performing the language task. Surprisingly, only a small region in the occipital cortex showed a significant activation difference (HC > PT(HCMV-)) when performing the visuospatial task. Targeted analyses revealed differences in gray matter volume, but not density, in several brain regions. Our results suggest that long-term neurobiological consequences of an early postnatal hCMV infection are detectable even in older children and adolescents formerly born very preterm, compatible with a higher effort when performing a cognitive task. This suggests that measures to prevent such an infection are warranted. Furthermore, an interrelation of brain structure and function was detected that may constitute a severe confound when using fMRI to compare structurally differing groups.

Localization of a major susceptibility locus influencing preterm birth

Preterm birth (PTB) is a complex trait, but little is known regarding its major genetic determinants. The objective of this study is to localize genes that influence susceptibility to PTB in Mexican Americans (MAs), a minority population in the USA, using predominantly microfilmed birth certificate-based data obtained from the San Antonio Family Birth Weight Study. Only 1302 singleton births from 288 families with information on PTB and significant covariates were considered for genetic analysis. PTB is defined as a childbirth that occurs at <37 completed weeks of gestation, and the prevalence of PTB in this sample was 6.4%. An ∼10 cM genetic map was used to conduct a genome-wide linkage analysis using the program SOLAR. The heritability of PTB was high (h(2) ± SE: 0.75 ± 0.20) and significant (P = 4.5 × 10(-5)), after adjusting for the significant effects of birthweight and birth order. We found significant evidence for linkage of PTB (LOD = 3.6; nominal P = 2.3 × 10(-5); empirical P = 1.0 × 10(-5)) on chromosome 18q between markers D18S1364 and D18S541. Several other chromosomal regions (2q, 9p, 16q and 20q) were also potentially linked with PTB. A strong positional candidate gene in the 18q linked region is SERPINB2 or PAI-2, a member of the plasminogen activator system that is associated with various reproductive processes. In conclusion, to our knowledge, perhaps for the first time in MAs or US populations, we have localized a major susceptibility locus for PTB on chromosome 18q21.33-q23.

Preterm birth and unintentional injuries: risks to children, adolescents and young adults show no consistent pattern

AIM

Preterm birth is associated with a number of physical and mental health issues. The aim of this study was to find out whether there was also any association between individuals born preterm in Sweden between 1984 and 2006 and the risk of unintentional injuries during childhood, adolescence and young adulthood.

METHODS

The study followed 2 297 134 individuals, including 5.9% born preterm, from 1985 to 2007 for unintentional injuries leading to hospitalization or death (n = 244 021). The males and females were divided into four age groups: 1-5 years, 6-12 years, 13-18 years and 19-23 years. Hazard ratios were calculated for falls, transport injuries and other injuries.

RESULTS

After adjusting for a comprehensive set of covariates, some of the preterm subgroups demonstrated slightly increased risks of unintentional injuries, while others showed slightly decreased risks. However, most of the estimates were borderline or non-significant in both males and females. In addition, the absolute risk differences between individuals born preterm and full term were small.

CONCLUSION

Despite the association between preterm birth and a variety of physical and mental health consequences, this study shows that there is no consistent risk pattern between preterm birth and unintentional injuries in childhood, adolescence and young adulthood.

Executive function and IQ predict mathematical and attention problems in very preterm children

Objective of this study was to examine the impact of executive function (EF) on mathematical and attention problems in very preterm (gestational age ≤ 30 weeks) children. Participants were 200 very preterm (mean age 8.2 ± 2.5 years) and 230 term children (mean age 8.3 ± 2.3 years) without severe disabilities, born between 1996 and 2004. EFs assessed included verbal fluency, verbal working memory, visuospatial span, planning, and impulse control. Mathematics was assessed with the Dutch Pupil Monitoring System and parents and teachers rated attention problems using standardized behavior questionnaires. The impact of EF was calculated over and above processing speed indices and IQ. Interactions with group (very preterm versus term birth status) were examined. Analyses were conducted separately for two subsamples: children in preschool and children in primary school. Very preterm children performed poorer on tests for mathematics and had more parent and teacher rated attention problems than term controls (ß(s)>.11, P(s)<.01). IQ contributed unique variance to mathematics in preschool and in primary school (ß(s)>.16, P(s)<.007). A significant interaction of group with IQ (ß = -. 24, P = .02) showed that IQ contributed unique variance to attention problems as rated by teachers, but that effects were stronger for very preterm than for term infants. Over and above IQ, EF contributed unique variance to mathematics in primary school (ß = .13, P<.001), to parent rated inattention in preschool and in primary school (ß(s)>-.16, P(s)<.04), and to teacher rated inattention in primary school (ß = -.19; ß = .19, P(s)<.009). In conclusion, impaired EF is, over and above impaired IQ, an important predictor for poor mathematics and attention problems following very preterm birth.

17-year outcome of preterm infants with diverse neonatal morbidities: Part 1--Impact on physical, neurological, and psychological health status

PURPOSE

The purpose of this study was to comprehensively examine physical, neurological, and psychological health in a U.S. sample of 180 infants at age 17.

DESIGN AND METHODS

The World Health Organization International Classification of Functioning, Disability and Health model framed the health-related domains and contextual factors. Assessments included growth, chronic conditions, neurological status, and psychological health.

RESULTS

Physical health, growth, and neurological outcomes were poorer in the preterm groups. Minor neurological impairment was related to integrative function. Preterm survivors reported higher rates of depression, anxiety, and inattention/hyperactivity.

PRACTICE IMPLICATIONS

Complex health challenges confront preterm survivors at late adolescence, suggesting the necessity of continued health surveillance.

Outcome of extremely low birth weight infants: what's new in the third millennium? Neuropsychological profiles at four years

BACKGROUND

Extremely low birth weight (ELBW) infants, even those not presenting severe neuromotor sequelae, continue to be at risk of developing multiple, complex disorders involving the cognitive, emotional and behavioural domains. Follow-up protocols are able, in the short term, to identify subjects at risk of developing major sequelae, however they fail to identify all children at risk of developing disorders.

AIMS

To investigate the cognitive, neuropsychological and behavioural outcomes of a sample of ELBW children at the age of four years in order to identify characteristic profiles.

STUDY DESIGN

Longitudinal study.

SUBJECTS

16 healthy ELBW children born in 2005 and followed up until the age of four.

OUTCOME MEASURE

Performances on standardised tests evaluating intelligence, memory, cognitive visual functions, attention, and executive functions.

RESULTS

General intelligence was within normal range. Cognitive profile showed mild or moderate deficits with different levels of involvement in many of the examined functions, in particular executive functions, attention and naming.

CONCLUSION

There emerged a wide-ranging spectrum of weaknesses and deficits involving all the functions examined, which together give rise to a dysexecutive syndrome. Analysis of cognitive profiles showed that the sample could be divided into two subgroups of subjects that differ in the quality of their global cognitive and behavioural functioning. Our results confirm the need to continue follow up of ELBW children until school age, as this will allow early detection of at-risk children and the planning of timely preventive interventions.

Characteristic Processes in Close Peer Friendships of Preterm Infants at Age 12

Close friendships become important at middle-school age and are unexplored in adolescents born prematurely. The study aimed to characterize friendship behaviors of formerly preterm infants at age 12 and explore similarities and differences between preterm and full-term peers on dyadic friendship types. From the full sample of N=186, one hundred sixty-six 12-year-old adolescents (40 born full term, 126 born preterm) invited a close friend to a 1.5 hour videotaped laboratory play session. Twenty adolescents were unable to participate due to scheduling conflicts or developmental disability. Characteristic friendship behaviors were identified by Q-sort followed by Q-factoring analysis. Friendship duration, age, and contact differed between the full-term and preterm groups but friendship activities, behaviors, and quality were similar despite school service use. Three Q-factors, leadership, distancing, and mutual playfulness, were most characteristic of all dyads, regardless of prematurity. These prospective, longitudinal findings demonstrate diminished prematurity effects at adolescence in peer friendship behavior and reveal interpersonal dyadic processes that are important to peer group affiliation and other areas of competence.

High prevalence/low severity language delay in preschool children born very preterm

OBJECTIVE

To examine the language development at corrected age 4 years of a regionally representative cohort of children born very preterm (VPT). Of particular interest was the identification of biological and socioenvironmental risk and protective factors that influence VPT children's early language development.

METHOD

Data were collected as part of a prospective longitudinal study of 110 VPT (VPT: ≤ 33 weeks gestation) and 113 full-term children (full term: 37-41 weeks gestation) born in Canterbury, New Zealand from 1998 to 2000. At corrected age 4 years, all children were assessed with the preschool version of the Clinical Evaluation of Language Fundamentals. Extensive information was also collected about children's family social background, perinatal health, childrearing environment, education/intervention exposures, and neurodevelopmental progress from birth to age 4.

RESULTS

At the age of 4 years, VPT children were characterized by poorer receptive and expressive language development than full-term children. These differences persisted after exclusion of children with neurosensory impairment as well as statistical adjustment for the effects of social risk. Within the VPT group, the key predictors of children's overall language development were family social risk at birth (p =.05), severity of white matter abnormalities on neonatal magnetic resonance imaging (p =.49), observed parent-child synchrony (p =.001), and concurrent child cognitive ability (p =.001). Together, these factors accounted for 45% of the variance in children's total Clinical Evaluation of Language Fundamentals-Preschool scores.

CONCLUSION

By preschool age, children born VPT show early emerging mild to moderate language delays that are likely to affect their school success and longer-term developmental progress. Findings highlight the importance of potentially modifiable factors such as early brain injury and parenting quality in predicting the language outcomes of children born VPT.

Variations of NICU sound by location and time of day

PURPOSE/AIMS

The primary aim of this study was to identify time periods of sound levels >45 decibels (dB) in a large Level III NICU. The second aim was to determine whether there were differences in decibel levels across the five bays of the NICU, the four quadrants within each bay, and two 12-hour shifts.

DESIGN

A repeated measures design was used. Bay, quadrant, and shift were randomly selected for sampling. Staff and visitors were blinded to the location of the sound meter, which was placed in one of five identical wooden boxes and was preset to record for 12 hours.

SAMPLE

Sound levels were recorded every 60 seconds over 40 12-hour periods, 20 during the day shift and 20 during the night shift. Total hours measured were 480. Data were collected every other day during a three-month period. Covariates of staffing, infant census, infant acuity, and medical equipment were collected.

MAIN OUTCOME VARIABLE

The main outcome variable was sound levels in decibels, with units of measurement of energy equivalent sound level (Leq), peak instantaneous sound pressure level, and maximum sound pressure level during each interval for a total of 480 hours.

RESULTS

All sound levels were >45 dB, with average readings ranging from 49.5 to 89.5 dB. The middle bay had the highest levels, with an Leq of 85.74 dB. Quadrants at the back of a bay were louder than quadrants at the front of a bay. The day shift had higher decibel levels than the night shift. Covariates did not differ across bays or shifts.

Improvement of short- and long-term outcomes for very low birth weight infants: Edmonton NIDCAP trial

OBJECTIVE

Our objective was to determine the impact of Newborn Individualized Developmental Care and Assessment Program (NIDCAP)-based care on length of stay of very low birth weight (VLBW) infants. Secondary outcome measures were days of ventilation, incidence of chronic lung disease, and 18-month neurodevelopmental outcomes.

METHODS

This cluster-randomized, controlled trial took place in a large NICU in Canada, with follow-up evaluation at 18 months of age, from September 1999 to September 2004. One hundred VLBW singleton infants and 10 VLBW twin sets were assigned randomly to NIDCAP-based or control care, and 90% participated in follow-up assessments. The intervention was NIDCAP-based care (N = 56), that is, care by NIDCAP-educated staff members and behavioral observations. The control group (N = 55) received standard NICU care. Statistical analyses were adjusted for cluster randomization. Although the intervention was not blinded, the pediatricians making the decisions to discharge the infants were not involved in the study, and the follow-up staff members were blinded with respect to group.

RESULTS

NIDCAP group infants had reduced length of stay (median: NIDCAP: 74 days; control: 84 days; P = .003) and incidence of chronic lung disease (NIDCAP: 29%; control: 49%; odds ratio: 0.42 [95% confidence interval: 0.18-0.95]; P = .035). At 18 months of adjusted age, NIDCAP group infants had less disability, specifically mental delay (NIDCAP: 10%; control: 30%; odds ratio: 0.25 [95% confidence interval: 0.08-0.82]; P = .017).

CONCLUSION

NIDCAP-based care for VLBW infants improved short- and long-term outcomes significantly.

Developmental origins theory from prematurity to adult disease

Developmental Origins Theory has received little coverage in the nursing literature, even though it has received much attention in other sciences. The theory proposes that prenatal stress provokes adaptive changes in endocrine and metabolic processes that become permanently programmed and impact later adult health. This paper reviews the theory and describes the primary neuroendocrine mechanism of hypothalamic-pituitary-adrenal axis function. Supporting research evidence in preterm infant and adult samples is presented. Through knowledge of the theory and the long-term sequelae for preterm infants, nurses will have a different theoretical perspective and growing evidence to consider in their care for pregnant women and infants.

A decade comparison of preterm motor performance at age 4

This was a prospective longitudinal study of two cohorts comprised of one full term and three premature infant groups born 10 years apart. Birth cohort, perinatal morbidity, and birth weight effects were investigated at age 4. Cohort 1 (1985-1989) had longer gestation, higher birth weight, and better Apgar scores than Cohort 2 (1996-1999), which had more intraventricular hemorrhage and bronchopulmonary dysplasia. Cohort and perinatal morbidity group, but not birth weight, predicted motor scores. Preterm Cohort 2 children had better oral motor, fine motor, and total motor scores, but lower visual motor integration scores than Cohort 1. Motor problems continue to affect preterm children at age 4, in particular those who experience perinatal morbidity, despite a decade of neonatal intensive care advancements.

Risk factors associated with developmental abnormalities among high-risk children attended at a multidisciplinary clinic

CONTEXT AND OBJECTIVE

Knowledge of risk factors associated with child development disorders is essential for delivering high-quality childcare. The objective here was to evaluate the relationships between risk factors and occurrences of developmental abnormalities among children attended at a reference clinic for children at risk of developmental abnormalities.

DESIGN AND SETTING

Retrospective study at a multidisciplinary reference center, Embu, São Paulo.

METHODS

All cases followed up for more than three months between 1995 and 2003 were reviewed. The risk factors assessed were low birth weight, gestational age, length of stay in neonatal ward, perinatal asphyxia, mothers age < 18 years, congenital infections, malformations and low mothers education level. Developmental abnormalities were defined according to developmental tests and assessments by the clinics professionals. The statistical analysis consisted of the chi-squared test for comparing categorical variables and a logistic regression model for multivariate analysis.

RESULTS

211 children were followed up for more than three months. Developmental abnormalities occurred in 111 (52.6%). Univariate analysis showed significant relationships between developmental abnormality and low birth weight, perinatal asphyxia, length of stay > 5 days, prematurity and mothers age 18 years and older. Low birth weight, history of perinatal asphyxia and mothers age continued to be significant in multivariate analysis.

CONCLUSIONS

Special attention must be paid to the development of low birth weight infants and/or infants with histories of neonatal complications. Low birth weight is easily assessed and should be considered to be an important marker when defining guidelines for following up child development.

Outcome Monitoring in Preterm Populations

Routine neurodevelopmental follow-up is crucial in high-risk populations, such as those born very preterm. Even in the absence of severe neurosensory impairment, very preterm children are at risk for a range of long-term cognitive, motor, and learning deficits. Infant developmental assessments are typically carried out at 2 years of age for both clinical and research purposes, and they are crucial for outcome monitoring. We review psychometric tests of infant developmental functioning most widely used as outcome measures for very preterm infants and other high-risk populations. We also consider parent-based assessments and methodological issues pertaining to the use of these tools in large-scale research studies and in outcome monitoring in this population.

Brain maturation of preterm newborn babies: new insights

Preterm birth still results in a high number of neurodevelopmental sequelae, although major forms of brain lesions--such as periventricular leukomalacia and intraventricular hemorrhage--are significantly reduced in this population of babies compared with a few years ago. This paper focuses on the possible reasons for this phenomenon. Some brain lesions, such as those affecting the periventricular white matter and the cerebellum, may be underestimated if magnetic resonance imaging is not used. In addition, a functional neurological consequence is not necessarily due to a recognized brain lesion, but may simply derive from an abnormally or suboptimally developed brain structure. The quality of nutrition given to a preterm baby could play a crucial role in such cases. In fact, nutrition is known to affect brain function; a case in point is the improvement in visual function resulting from dietary essential fatty acids. Finally, research in this area should aim at both reducing potential hazards and improving the quality of perinatal care, including the quality of nutrition.

Cognitive and behavioural outcomes following very preterm birth

This paper provides a review of the cognitive and behavioural outcomes of very preterm children in middle childhood. Case-controlled studies have shown that very preterm children have intelligence quotient (IQ) scores significantly lower than term peers, even for those who are free of severe disability. Authors have noted a gestational age-related gradient in IQ for those born before 33 weeks and studies have revealed particular problems in non-verbal reasoning and simultaneous information processing. Very preterm children are also at risk for behavioural problems. There is little consensus regarding the presence of internalising or externalising behaviours, but most studies show an increased risk of attentional and social problems. Studies have also shown a greater prevalence of psychiatric disorders and, specifically, an increased risk for ADHD. Methodological issues are discussed and suggestions are made for improving the reporting of outcomes to facilitate cross-study comparisons.

The association of early blood oxygenation with child development in preterm infants with acute respiratory disorders

The potential negative impact of early blood oxygenation on development of specific cognitive and motor outcomes in children born at very low birth weight (VLBW; 1000-1500g) has not been examined even though these infants are exposed to varying durations and amounts of oxygen as part of their neonatal care. While this is the largest group of preterm infants, they receive much less research attention than extremely low birth weight infants (ELBW<1000g). Although neonatologists are questioning the routine use of oxygen therapy for all neonates, research has focused primarily on the more medically fragile ELBW infants. To date there are no systematic studies available to guide decision making for oxygen supplementation for a large segment of the preterm infant population. The aim of the present study was to determine if there is an association between blood oxygenation in the first 4h of life and specific cognitive and motor skills in preterm infants with acute respiratory disorders but no severe intracranial insult using a selected cohort from a longitudinal study children recruited in 1991 and 1992 designed to examine the role of biological immaturity as defined by gestational age and parenting in development. From this cohort, 55 children had acute respiratory disorders without severe intracranial insult. Of these, 35 children had at least one partial pressure of oxygen obtained from arterial blood (PaO2) during the first 4h of life as part of their clinical care. Higher early PaO2 values were associated with lower impulse control and attention skills in the elementary school age period. Models that were examined for relations between PaO2 values that also included birth weight and parenting quality across the first year of life revealed that higher PaO2 remained associated with impulse control but not attention skills. Birth weight was not associated with any outcomes. These results suggest that hyperoxia may be a risk factor for developmental problems that are not expressed until school age.

A validation study of the Norwegian version of the Ages and Stages Questionnaires

AIM

To explore the construct validity of the ASQ in relation to premature birth; maternal age, completeness of the family and level of education; and the child's gender.

METHODS

Norwegian mothers' evaluations of 1172 children who completed age appropriate ASQs twice were statistically analysed by means of univariate and multivariate methods.

RESULTS

The developmental level of girls is on average higher than that of boys at both assessments and there is a substantial increase between follow-up assessments in all ASQ scores except for gross motor skills. The mother's level of education; whether the child was born prematurely or at full-term; and the interaction between the child's gender and his/her mother's level of education are important factors relating to the child's developmental status in both assessments.

CONCLUSION

The results that were derived by means of the Ages and Stages Questionnaires concerning the impact of maternal socio-demographical factors, the child's gender, and premature birth upon early childhood development largely confirm the findings in the literature supporting the construct validity of the ASQ. The ASQ was found to be an effective diagnostic tool of developmental delay and/or disturbances. The development of gender dependent norms is recommended.

Pediatric in-intensive-care-unit cardiac arrest: incidence, survival, and predictive factors

OBJECTIVE

To describe the incidence, survival, and neurologic outcome of in-intensive-care-unit (ICU) cardiac arrest and to identify factors predictive of survival to hospital discharge.

METHODS

We performed a retrospective cohort study. Eligible patients were <18 yrs of age and experienced a cardiac arrest during their admission to a multidisciplinary pediatric intensive care unit in the 5.5-yr period ending June 2002. Cardiac arrest was defined as the administration of chest compressions or defibrillation for a nonperfusing cardiac rhythm. Mortality and the Paediatric Cerebral Performance Score were measured and presented according to the Utstein style. Factors predictive of survival to hospital discharge were identified by univariate analysis and independent predictors were identified by multivariate analysis.

MAIN MEASUREMENTS AND RESULTS

Ninety-one children had cardiac arrest, yielding an incidence of 0.94 cardiac arrests per 100 admissions. Resuscitation was successful in 75 (82%) children, 61 (67%) survived 24 hrs, 25 (27%) children survived to ICU discharge and 23 (25%) to hospital discharge. At hospital discharge, the median Pediatric Cerebral Performance Category score was 2 (range, 1-3) and the median Pediatric Overall Performance Category score was 3 (range, 1-4). No child was assessed as normal on both scores. The independent positive predictors of hospital mortality were the presence of renal failure before cardiac arrest (odds ratio [OR], 6.1; 95% confidence interval [CI], 1.8-31), being on epinephrine infusion at time of cardiac arrest (OR, 9.5; 95% CI, 1.5-62), and the administration of one or more calcium boluses during resuscitation (OR, 5.4; 95% CI, 1.1-25). The use of extracorporeal membrane oxygenation (ECMO) within 24 hrs after cardiac arrest was associated with reduced hospital mortality (OR, 0.18; 95% CI, 0.04-0.76).

CONCLUSIONS

In-ICU cardiac arrest is associated with high in-hospital mortality and subsequent morbidity in survivors. Prearrest renal dysfunction and epinephrine infusion were associated with increased in-hospital mortality. The use of post-arrest ECMO within 24 hrs was associated with reduced mortality. Rigorous prospective evaluation of the role of ECMO following cardiac arrest is needed.

Outcome of extreme prematurity: as information increases so do the dilemmas

Application of technology in neonatal intensive care has been very successful in reducing mortality, particularly in extremely low birthweight infants. As survival has improved, the need for accurate studies of long term outcome has increased. This need has been met by studies that are larger, more inclusive, and address a wider variety of later outcomes. Rather than a comprehensive quantitative review of these studies, this article uses a smaller number of studies that focus on infants of borderline viability, to illustrate current dilemmas and challenges in interpretation, and the actions, both individual and societal, that may be prompted by these interpretations.

Developmental screen or developmental testing?

Given the high risk for residual disability in preterm infants, outcome monitoring is a crucial function of neonatal care. Provision of neurodevelopmental follow-up to at least 2 years of age corrected for prematurity forms part of national recommendations for neonatal services. This should include a developmental assessment at 2 years to identify disability. Although screening tools are cost and time efficient measures, they are not diagnostic and have less utility in high-risk populations. In contrast, standardised developmental tests are ideally suited for follow-up purposes and have become widely accepted as outcome measures. We highlight the properties of standardised tests and review the most commonly used tools for assessment in infancy. We also outline a number of practical issues in the use of standardised tests with preterm infants in identifying morbidity and predicting later impairment. Parental reports are also discussed and key guidelines for developmental testing at 2 years are provided.

Neurodevelopmental outcomes of infants born prematurely

Long-term follow-up of infants born prematurely is necessary to determine neurodevelopmental outcomes, particularly with the expansion of interest from major disabilities to high prevalence/low severity dysfunctions. Models of pathogenesis include changes due to developmental disruptions and to injury, the magnitude and type of change influenced by the infant's age, and central nervous system recovery and reorganization. Alterations in neurogenesis, migration, myelination, cell death, and synaptogenesis occur even in the absence of insult. Despite increased knowledge regarding these processes, the functional significance of brain abnormalities is unclear. Because of methodologic problems in follow-up studies, it is difficult to characterize outcome definitively. Nonetheless, an acceptable degree of agreement across studies is found with regard to specific neurodevelopmental outcomes: motor/neurologic function, visuomotor integrative skills, IQ, academic achievement, language, executive function, and attention-deficit hyperactivity disorder/behavioral issues. In general, children born prematurely have more problems in these areas than do their normal birth weight counterparts. Suggestions for improved analyses and clarification of outcomes include use of cluster analysis, structural equation modeling, growth curve analysis, developmental epidemiologic approaches, and better control of background variables using risk indexes and factor scores. Better assessment techniques measuring functions documented to be at higher risk of problems are discussed.

Methylxanthine Therapy for Apnea of Prematurity: Evaluation of Treatment Benefits and Risks at Age 5 Years in the International Caffeine for Apnea of Prematurity (CAP) Trial

Methylxanthine therapy reduces the frequency of apnea and the need for mechanical ventilation. Recent research has raised concerns about the safety of methylxanthines in very preterm infants. Possible adverse effects include poor growth, worsening of hypoxic-ischemic brain damage and abnormal childhood behavior. Over 2,000 infants with birth weights 500-1,250 g have been randomized in the international placebo-controlled Caffeine for Apnea of Prematurity (CAP) trial to examine the long-term efficacy and safety of methylxanthine therapy for the management of apnea of prematurity. Additional therapies such as continuous positive airway pressure were used as necessary to control apneic attacks. At 18 months we measure the combined rate of death or survival with one or more of the following impairments: cerebral palsy, cognitive deficit, blindness and deafness. This outcome was chosen because of the need to evaluate the impact of common neonatal therapies beyond discharge from the intensive care unit. However, several potential long-term consequences of methylxanthine therapy may not become apparent until the study cohort reaches pre-school age. We will therefore extend the follow-up to age 5 years. The main outcome at 5 years will be a composite of death or survival with severe disability in at least one of six domains: cognition, neuromotor function, vision, hearing, behavior, and general health. Once this project is completed, caffeine will be one of the most rigorously evaluated neonatal therapies.

Preterm birth: a cost benefit analysis

Advances in prenatal and perinatal treatment of preterm and VLBW infants have dramatically increased the survival rate of these infants. Some interventions decrease long term sequelae associated with preterm birth, making them more cost-effective than other treatments. This paper reviews the cost-effectiveness of therapies targeted to protect the preterm brain. Birth in a center with a NICU improves survival and decreases the rate of severe neurologic disability. Administration of antenatal steroids increases survival and decreases rates of periventricular hemorrhage, periventricular leukomalacia, necrotizing enterocolitis, respiratory distress syndrome, and severe disability. Administration of antenatal steroids decreases costs per additional survivor. Addition of surfactant to the treatment of PT infants has also decreased treatment costs. Administration of surfactant is beneficial for symptomatic RDS but recognizes a greater benefit when given to infants younger than 30 weeks gestation prophylactically. Treatment with prophylactic indomethacin decreases the rate of intraventricular hemorrhage and results in cost savings in survivors. Postnatal administration of dexamethasone can lead to severe disability when administered before 7 to 10 days of life. Postnatal dexamethasone does not increase survival or decrease rates of chronic lung disease.

Les troubles du développement des enfants grands prématurés mesurés à l’âge scolaire

Advances in perinatal care have lead to the survival of an increasing number of children born very premature. The purpose of this review is to discuss findings in the literature regarding long term developmental outcome of infants born prematurely especially for studies with children at least 5 years old, born in the 80's or after, in a context of care with increased use of antenatal corticoids, in utero transfer, and surfactant therapy. Developmental sequelae, which are seen in children older than those presenting severe deficiencies, concerns a greater number of very premature children. They have poorer outcomes than term children or normal birth weight controls for cognitive-neuropsychological skills, school performances and behavior. Long term follow up of these children shows that consequences are still present for adolescents or young adults. There is a gradient of developmental sequelae in children that is inversely related to decreasing gestational age or birth weight. Developmental sequelae are related to neonatal medical complications and social risks factors. Research should be conducted in order to better understand etiology and neuropathological basis of sequelae, and the long term developmental implication of being born very premature and the type of care or intervention which could improve their development. An early and regular follow up by a team specialized in child development should be proposed in order to detect developmental sequelae and propose early intervention.