Preterm birth and neurodevelopment: a review of outcomes and recommendations for early identification and cost-effective interventions

The INTERGROWTH-21st Project Neurodevelopment Package: a novel method for the multi-dimensional assessment of neurodevelopment in pre-school age children

BACKGROUND

The International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st) Project is a population-based, longitudinal study describing early growth and development in an optimally healthy cohort of 4607 mothers and newborns. At 24 months, children are assessed for neurodevelopmental outcomes with the INTERGROWTH-21st Neurodevelopment Package. This paper describes neurodevelopment tools for preschoolers and the systematic approach leading to the development of the Package.

METHODS

An advisory panel shortlisted project-specific criteria (such as multi-dimensional assessments and suitability for international populations) to be fulfilled by a neurodevelopment instrument. A literature review of well-established tools for preschoolers revealed 47 candidates, none of which fulfilled all the project's criteria. A multi-dimensional assessment was, therefore, compiled using a package-based approach by: (i) categorizing desired outcomes into domains, (ii) devising domain-specific criteria for tool selection, and (iii) selecting the most appropriate measure for each domain.

RESULTS

The Package measures vision (Cardiff tests); cortical auditory processing (auditory evoked potentials to a novelty oddball paradigm); and cognition, language skills, behavior, motor skills and attention (the INTERGROWTH-21st Neurodevelopment Assessment) in 35-45 minutes. Sleep-wake patterns (actigraphy) are also assessed. Tablet-based applications with integrated quality checks and automated, wireless electroencephalography make the Package easy to administer in the field by non-specialist staff. The Package is in use in Brazil, India, Italy, Kenya and the United Kingdom.

CONCLUSIONS

The INTERGROWTH-21st Neurodevelopment Package is a multi-dimensional instrument measuring early child development (ECD). Its developmental approach may be useful to those involved in large-scale ECD research and surveillance efforts.

Hospital admissions and gestational age at birth: 18 years of follow up in Western Australia

BACKGROUND

Infants born moderate to late preterm are twice as likely to be rehospitalised within the first few weeks following discharge from the birth admission. It is not understood how rehospitalisation risk changes with age or how risks have changed over time.

METHODS

A retrospective birth cohort study of all live, singleton births in Western Australia 1 January 1980-31 December 2010, without congenital anomalies, followed to 18 years of age. Rehospitalisation rates for gestational age categories (<28, 28-31, 32-33, 34-36, 37-38 and ≥42 weeks) were compared with term births (39-41 weeks) using negative binomial regression. To assess whether rehospitalisation risk changed with age or over time, analyses were conducted for different age intervals and for 5-year birth cohorts.

RESULTS

Rehospitalisation rates were higher up to 18 years for all preterm and early term categories including early term (37-38 weeks) [130.2/1000 person-years at risk (pyr); 95% confidence interval 129.1, 131.4]; late preterm (34-36 weeks) (164.2/1000 pyr; 161.1, 167.4), and post-term (≥42 weeks) (115.3/1000 pyr; 111.7, 119.0) compared with term births (109.1/1000 pyr; 108.5, 109.7). The effect of gestational age on rehospitalisation was highest during the first year of life and declined by adolescence [e.g. 34-36 weeks: rate ratio = 2.10 (2.04, 2.15) for 29 days-1 year; 1.14 (1.11, 1.18) for 12-18 years]. The risk of rehospitalisation up to 1 year of age has declined since 1980, except for those born <32 weeks.

CONCLUSIONS

Rehospitalisation risk is greater for singleton children born at all gestational ages compared with those born full term. This effect of gestational age on rehospitalisation is highest in the first year post-discharge, but has almost disappeared by adolescence.

The common antitussive agent dextromethorphan protects against hyperoxia-induced cell death in established in vivo and in vitro models of neonatal brain injury

Preterm infants are prematurely subjected to relatively high oxygen concentrations, even when supplemental oxygen is not administered. There is increasing evidence to show that an excess of oxygen is toxic to the developing brain. Dextromethorphan (DM), a frequently used antitussive agent with pleiotropic mechanisms of action, has been shown to be neuroprotective in various models of central nervous system pathology. Due to its numerous beneficial properties, it might also be able to counteract detrimental effects of a neonatal oxygen insult. The aim of the current study was to evaluate its therapeutic potential in established cell culture and rodent models of hyperoxia-induced neonatal brain injury. For in vitro studies pre- and immature oligodendroglial (OLN-93) cells were subjected to hyperoxic conditions for 48 h after pre-treatment with increasing doses of DM. For in vivo studies 6-day-old Wistar rat pups received a single intraperitoneal injection of DM in two different dosages prior to being exposed to hyperoxia for 24h. Cell viability and caspase-3 activation were assessed as outcome parameters at the end of exposure. DM significantly increased cell viability in immature oligodendroglial cells subjected to hyperoxia. In pre-oligodendroglial cells cell viability was not significantly affected by DM treatment. In vivo caspase-3 activation induced by hyperoxic exposure was significantly lower after administration of DM in gray and white matter areas. In control animals kept under normoxic conditions DM did not significantly influence caspase-3-dependent apoptosis. The present results indicate that DM is a promising and safe treatment strategy for neonatal hyperoxia-induced brain injury that merits further investigation.

Cognitive and language outcomes in HIV-uninfected infants exposed to combined antiretroviral therapy in utero and through extended breast-feeding

OBJECTIVE

To determine whether there is a higher risk for cognitive or language delay among HIV-exposed uninfected (HEU) children exposed to cART (zidovudine/lamivudine/lopinavir/ritonavir) in utero and through 1 year of breast-feeding (World health Organization Option B+), compared with the control children born to HIV-uninfected mothers.

DESIGN

This is a double cohort study from Lusaka, Zambia.

METHODS

HEU (n = 97) and control (n = 103) children aged 15-36 months were assessed on their early nonverbal problem-solving and language skills using the standardized Capute Scales. A score of less than 85 on the Capute Full-Scale Developmental Quotient (FSDQ) was considered indicative of developmental delay and was the primary outcome of interest.

RESULTS

An FSDQ of less than 85 was found in eight (8.3%) of HEU participants and 15 (14.6%) of controls. In univariate logistic regressions, lower income [odds ratio (OR) = 0.93, P = 0.02], older infant age (OR = 1.08, P = 0.03), lower birth weight (OR = 0.16, P < 0.001), and less maternal education (OR = 0.41, P = 0.047) were associated with the probability of FSDQ less than 85, whereas Group (control/HEU) was not (OR = 1.88, P = 0.16). In the multivariable analysis, only lower birth weight (OR = 0.15, P < 0.001) remained associated with FSDQ less than 85.

CONCLUSIONS

Our study did not support the presence of an adverse effect on cognitive and language development with prolonged antepartum and postpartum cART e/xposure. Larger studies and studies of older HEU children will be required to confirm these reassuring findings.

Perinatal biomarkers in prematurity: early identification of neurologic injury

Over the past few decades, biomarkers have become increasingly utilized as non-invasive tools in the early diagnosis and management of various clinical conditions. In perinatal medicine, the improved survival of extremely premature infants who are at high risk for adverse neurologic outcomes has increased the demand for the discovery of biomarkers in detecting and predicting the prognosis of infants with neonatal brain injury. By enabling the clinician to recognize potential brain damage early, biomarkers could allow clinicians to intervene at the early stages of disease, and to monitor the efficacy of those interventions. This review will first examine the potential perinatal biomarkers for neurologic complications of prematurity, specifically, intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL) and posthemorrhagic hydrocephalus (PHH). It will also evaluate knowledge gained from animal models regarding the pathogenesis of perinatal brain injury in prematurity.

Brain MRI measurements at a term-equivalent age and their relationship to neurodevelopmental outcomes

BACKGROUND AND PURPOSE

An increased prevalence of disabilities is being observed as more preterm infants survive. This study was conducted to evaluate correlations between brain MR imaging measurements taken at a term-equivalent age and neurodevelopmental outcome at 2 years' corrected age among very low-birth-weight infants.

MATERIALS AND METHODS

Of the various brain MR imaging measurements obtained at term-equivalent ages, reproducible measurements of the transcerebellar diameter and anteroposterior length of the corpus callosum on sagittal images were compared with neurodevelopmental outcomes evaluated by the Bayley Scales of Infant Development (II) at 2 years' corrected age (mean ± standard deviation, 16.1 ± 6.4 months of age).

RESULTS

Ninety infants were enrolled. The mean gestational age at birth was 27 weeks and the mean birth weight was 805.5 g. A short corpus callosal length was associated with a Mental Developmental Index <70 (P = .047) and high-risk or diagnosed cerebral palsy (P = .049). A small transcerebellar diameter was associated with a Psychomotor Developmental Index <70 (P = .003), Mental Developmental Index <70 (P = .004), and major neurologic disability (P = .006).

CONCLUSIONS

A small transcerebellar diameter and short corpus callosal length on brain MR imaging at a term-equivalent age are related to adverse neurodevelopmental outcomes at a corrected age of 2 years and could be a useful adjunctive tool for counseling parents about future developmental outcomes.