Moderate and late preterm infants exhibit widespread brain white matter microstructure alterations at term-equivalent age relative to term-born controls

Alteration of fractional anisotropy in preterm-born individuals: a systematic review and meta-analysis

BACKGROUD

Neurological disorders are common in preterm (PT) born individuals. Diffusion tensor imaging (DTI) studies using tract-based spatial statistics (TBSS) effectively detect microstructural white matter (WM) abnormalities in the brain. We conducted this systematic review to integrate the findings of TBSS studies to determine the most consistent WM alterations in PT born individuals.

METHODS

PubMed, Embase, Web of Science and Science Direct were searched. DTI studies using TBSS in PT born individuals were screened up to October 2022. The systematic review included studies reporting alterations in FA values for the entire brain in a stereotactic space, with three coordinates (x, y, z), according to the seed-based d mapping method.

RESULTS

The search strategy identified seventeen studies that fulfilled our inclusion criteria, with a total of 911 PT-born individuals and 563 matched controls were analysed. Of the seventeen studies, eight were dedicated to 650 adults, five to 411 children and four to 413 infants. Ten studies recruited 812 individuals born very prematurely (GA <29 weeks), six studies recruited 386 moderately premature individuals (GA = 29-32 weeks) and one study recruited 276 individuals born late prematurely (GA >32 weeks). This meta-analysis of six studies including 388 individuals highlighted four brain regions in which fractional anisotropy (FA) was lower in PT group than in people born at term. The quantitative meta-analysis found that the most robust WM alterations were located in the corpus callosum (CC), the bilateral thalamus and the left superior longitudinal fasciculus (SLF) II. Significant changes in FA reflect WM abnormalities in PT born individuals from infant to young adulthood.

CONCLUSIONS

Significant changes in FA reflect WM abnormalities in individuals born PT from infancy to young adulthood. The abnormal development of the CC, bilateral thalamus and left SLF may play a vital role in the neurodevelopment of PT individuals.

Assessing Neonatal Intensive Care Unit (NICU) Graduates Across Varied Settings: A Study on the Feasibility of the Baby Moves App

We assessed the feasibility of obtaining parent-collected General Movement Assessment videos using the Baby Moves app. Among 261 participants from 4 Chicago NICUs, 70% submitted videos. Families living in higher areas of childhood opportunity used the app more than those from areas of lower opportunity.

Structural Changes in the Brain on Magnetic Resonance Imaging in Malnourished Children: A Scoping Review of the Literature

BACKGROUND

This review was conducted to summarize the current evidence on the structural findings seen in brain magnetic resonance imaging (MRI) in malnourished children and the effect of optimized nutritional supplementation on brain development as studied through MRI.

METHODS

A systematic search was carried out in PubMed, Embase, The Cochrane Library, Web of Science (Clarivate Analytics), WHO ICTRP Clinical Trials in Children, and ClinicalTrials.gov using a predefined search criterion for relevant literature from inception to January 2022. The primary outcome of the study was structural changes observed in the brain on MRI.

RESULTS

The most common abnormal findings on MRI in malnourished infants were cerebral atrophy and dilated ventricles. Furthermore, a higher proportion of breast milk, calorie, and lipid intake in the diet was significantly associated with increased brain volumes; this also increased the likelihood of normal MRI scores at term. When followed till adolescence, it was observed that these infants had increased neonatal weight gain and a higher intelligence quotient when compared with the group.

CONCLUSIONS

In conclusion, most children with moderate/severe malnutrition had abnormal MRI findings, mostly cerebral atrophy with or without ventricular dilatation. Since none of the studies measured the degree of atrophy or ventricular dilatation, it was not possible to assess the effect of the severity of malnutrition on brain atrophy. A universal measurement or scoring system for assessing the degree of brain atrophy is needed to help correlate the severity of malnutrition with the degree of brain atrophy and monitor the effects of nutritional rehabilitation over time.

Immuno-epigenetic signature derived in saliva associates with the encephalopathy of prematurity and perinatal inflammatory disorders

BACKGROUND

Preterm birth is closely associated with a phenotype that includes brain dysmaturation and neurocognitive impairment, commonly termed Encephalopathy of Prematurity (EoP), of which systemic inflammation is considered a key driver. DNA methylation (DNAm) signatures of inflammation from peripheral blood associate with poor brain imaging outcomes in adult cohorts. However, the robustness of DNAm inflammatory scores in infancy, their relation to comorbidities of preterm birth characterised by inflammation, neonatal neuroimaging metrics of EoP, and saliva cross-tissue applicability are unknown.

METHODS

Using salivary DNAm from 258 neonates (n = 155 preterm, gestational age at birth 23.28 - 34.84 weeks, n = 103 term, gestational age at birth 37.00 - 42.14 weeks), we investigated the impact of a DNAm surrogate for C-reactive protein (DNAm CRP) on brain structure and other clinically defined inflammatory exposures. We assessed i) if DNAm CRP estimates varied between preterm infants at term equivalent age and term infants, ii) how DNAm CRP related to different types of inflammatory exposure (maternal, fetal and postnatal) and iii) whether elevated DNAm CRP associated with poorer measures of neonatal brain volume and white matter connectivity.

RESULTS

Higher DNAm CRP was linked to preterm status (-0.0107 ± 0.0008, compared with -0.0118 ± 0.0006 among term infants; p < 0.001), as well as perinatal inflammatory diseases, including histologic chorioamnionitis, sepsis, bronchopulmonary dysplasia, and necrotising enterocolitis (OR range |2.00 | to |4.71|, p < 0.01). Preterm infants with higher DNAm CRP scores had lower brain volume in deep grey matter, white matter, and hippocampi and amygdalae (β range |0.185| to |0.218|). No such associations were observed for term infants. Association magnitudes were largest for measures of white matter microstructure among preterms, where elevated epigenetic inflammation associated with poorer global measures of white matter integrity (β range |0.206| to |0.371|), independent of other confounding exposures.

CONCLUSIONS

Inflammatory-related DNAm captures the allostatic load of inflammatory burden in preterm infants. Such DNAm measures complement biological and clinical metrics when investigating the determinants of neurodevelopmental differences.

Detailed anatomic segmentations of a fetal brain diffusion tensor imaging atlas between 23 and 30 weeks of gestation

This work presents detailed anatomic labels for a spatiotemporal atlas of fetal brain Diffusion Tensor Imaging (DTI) between 23 and 30 weeks of post-conceptional age. Additionally, we examined developmental trajectories in fractional anisotropy (FA) and mean diffusivity (MD) across gestational ages (GA). We performed manual segmentations on a fetal brain DTI atlas. We labeled 14 regions of interest (ROIs): cortical plate (CP), subplate (SP), Intermediate zone-subventricular zone-ventricular zone (IZ/SVZ/VZ), Ganglionic Eminence (GE), anterior and posterior limbs of the internal capsule (ALIC, PLIC), genu (GCC), body (BCC), and splenium (SCC) of the corpus callosum (CC), hippocampus, lentiform Nucleus, thalamus, brainstem, and cerebellum. A series of linear regressions were used to assess GA as a predictor of FA and MD for each ROI. The combination of MD and FA allowed the identification of all ROIs. Increasing GA was significantly associated with decreasing FA in the CP, SP, IZ/SVZ/IZ, GE, ALIC, hippocampus, and BCC (p < .03, for all), and with increasing FA in the PLIC and SCC (p < .002, for both). Increasing GA was significantly associated with increasing MD in the CP, SP, IZ/SVZ/IZ, GE, ALIC, and CC (p < .03, for all). We developed a set of expert-annotated labels for a DTI spatiotemporal atlas of the fetal brain and presented a pilot analysis of developmental changes in cerebral microstructure between 23 and 30 weeks of GA.

Preterm birth and neonatal white matter microstructure in in-vivo reconstructed fiber tracts among audiovisual integration brain regions

Individuals born preterm are at risk of developing a variety of sequelae. Audiovisual integration (AVI) has received little attention despite its facilitating role in the development of socio-cognitive abilities. The present study assessed the association between prematurity and in-vivo reconstructed fiber bundles among brain regions relevant for AVI. We retrieved data from 63 preterm neonates enrolled in the Developing Human Connectome Project (http://www.developingconnectome.org/) and matched them with 63 term-born neonates from the same study by means of propensity score matching. We performed probabilistic tractography, DTI and NODDI analysis on the traced fibers. We found that specific DTI and NODDI metrics are significantly associated with prematurity in neonates matched for postmenstrual age at scan. We investigated the spatial overlap and developmental order of the reconstructed tractograms between preterm and full-term neonates. Permutation-based analysis revealed significant differences in dice similarity coefficients and developmental order between preterm and full term neonates at the group level. Contrarily, no group differences in the amount of interindividual variability of DTI and NODDI metrics were observed. We conclude that microstructural detriment in the reconstructed fiber bundles along with developmental and morphological differences are likely to contribute to disadvantages in AVI in preterm individuals.

Associations between neurological examination at term-equivalent age and cerebral hemodynamics and oxygen metabolism in infants born preterm

Background

Infants born at 29-36 weeks gestational age (GA) are at risk of experiencing neurodevelopmental challenges. We hypothesize that cerebral hemodynamics and oxygen metabolism measured by bedside optical brain monitoring are potential biomarkers of brain development and are associated with neurological examination at term-equivalent age (TEA).

Methods

Preterm infants (N = 133) born 29-36 weeks GA and admitted in the neonatal intensive care unit were enrolled in this prospective cohort study. Combined frequency-domain near infrared spectroscopy (FDNIRS) and diffuse correlation spectroscopy (DCS) were used from birth to TEA to measure cerebral hemoglobin oxygen saturation and an index of microvascular cerebral blood flow (CBF _i ) along with peripheral arterial oxygen saturation (SpO₂). In combination with hemoglobin concentration in the blood, these parameters were used to derive cerebral oxygen extraction fraction (OEF) and an index of cerebral oxygen metabolism (CMRO_2i ). The Amiel-Tison and Gosselin Neurological Assessment was performed at TEA. Linear regression models were used to assess the associations between changes in FDNIRS-DCS parameters from birth to TEA and GA at birth. Logistic regression models were used to assess the associations between changes in FDNIRS-DCS parameters from birth to TEA and neurological examination at TEA.

Results

Steeper increases in CBF _i (p < 0.0001) and CMRO_2i (p = 0.0003) were associated with higher GA at birth. Changes in OEF, CBF _i , and CMRO_2i from birth to TEA were not associated with neurological examination at TEA.

Conclusion

In this population, cerebral FDNIRS-DCS parameters were not associated with neurological examination at TEA. Larger increases in CBF _i and CMRO_2i from birth to TEA were associated with higher GA. Non-invasive bedside FDNIRS-DCS monitoring provides cerebral hemodynamic and metabolic parameters that may complement neurological examination to assess brain development in preterm infants.

Early structural connectivity within the sensorimotor network: Deviations related to prematurity and association to neurodevelopmental outcome

Consisting of distributed and interconnected structures that interact through cortico-cortical connections and cortico-subcortical loops, the sensorimotor (SM) network undergoes rapid maturation during the perinatal period and is thus particularly vulnerable to preterm birth. However, the impact of prematurity on the development and integrity of the emerging SM connections and their relationship to later motor and global impairments are still poorly understood. In this study we aimed to explore to which extent the early microstructural maturation of SM white matter (WM) connections at term-equivalent age (TEA) is modulated by prematurity and related with neurodevelopmental outcome at 18 months corrected age. We analyzed 118 diffusion MRI datasets from the developing Human Connectome Project (dHCP) database: 59 preterm (PT) low-risk infants scanned near TEA and a control group of full-term (FT) neonates paired for age at MRI and sex. We delineated WM connections between the primary SM cortices (S1, M1 and paracentral region) and subcortical structures using probabilistic tractography, and evaluated their microstructure with diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) models. To go beyond tract-specific univariate analyses, we computed a maturational distance related to prematurity based on the multi-parametric Mahalanobis distance of each PT infant relative to the FT group. Our results confirmed the presence of microstructural differences in SM tracts between PT and FT infants, with effects increasing with lower gestational age at birth. Maturational distance analyses highlighted that prematurity has a differential effect on SM tracts with higher distances and thus impact on (i) cortico-cortical than cortico-subcortical connections; (ii) projections involving S1 than M1 and paracentral region; and (iii) the most rostral cortico-subcortical tracts, involving the lenticular nucleus. These different alterations at TEA suggested that vulnerability follows a specific pattern coherent with the established WM caudo-rostral progression of maturation. Finally, we highlighted some relationships between NODDI-derived maturational distances of specific tracts and fine motor and cognitive outcomes at 18 months. As a whole, our results expand understanding of the significant impact of premature birth and early alterations on the emerging SM network even in low-risk infants, with possible relationship with neurodevelopmental outcomes. This encourages further exploration of these potential neuroimaging markers for prediction of neurodevelopmental disorders, with special interest for subtle neuromotor impairments frequently observed in preterm-born children.

Adult outcome of preterm birth: Implications for neurodevelopmental theories of psychosis

Preterm birth is associated with an elevated risk of developmental and adult psychiatric disorders, including psychosis. In this review, we evaluate the implications of neurodevelopmental, cognitive, motor, and social sequelae of preterm birth for developing psychosis, with an emphasis on outcomes observed in adulthood. Abnormal brain development precipitated by early exposure to the extra-uterine environment, and exacerbated by neuroinflammation, neonatal brain injury, and genetic vulnerability, can result in alterations of brain structure and function persisting into adulthood. These alterations, including abnormal regional brain volumes and white matter macro- and micro-structure, can critically impair functional (e.g. frontoparietal and thalamocortical) network connectivity in a manner characteristic of psychotic illness. The resulting executive, social, and motor dysfunctions may constitute the basis for behavioural vulnerability ultimately giving rise to psychotic symptomatology. There are many pathways to psychosis, but elucidating more precisely the mechanisms whereby preterm birth increases risk may shed light on that route consequent upon early neurodevelopmental insult.

The Signature of Moderate Perinatal Hypoxia on Cortical Organization and Behavior: Altered PNN-Parvalbumin Interneuron Connectivity of the Cingulate Circuitries

This study was designed in a rat model to determine the hallmarks of possible permanent behavioral and structural brain alterations after a single moderate hypoxic insult. Eighty-two Wistar Han (RccHan: WIST) rats were randomly subjected to hypoxia (pO2 73 mmHg/2 h) or normoxia at the first postnatal day. The substantially increased blood lactate, a significantly decreased cytochrome-C-oxygenase expression in the brain, and depleted subventricular zone suggested a high vulnerability of subset of cell populations to oxidative stress and consequent tissue response even after a single, moderate, hypoxic event. The results of behavioral tests (open-field, hole-board, social-choice, and T-maze) applied at the 30–45th and 70–85th postnatal days revealed significant hyperactivity and a slower pace of learning in rats subjected to perinatal hypoxia. At 3.5 months after hypoxic insult, the histochemical examination demonstrated a significantly increased number of specific extracellular matrix—perineuronal nets and increased parvalbumin expression in a subpopulation of interneurons in the medial and retrosplenial cingulate cortex of these animals. Conclusively, moderate perinatal hypoxia in rats causes a long-lasting reorganization of the connectivity in the cingulate cortex and consequent alterations of related behavioral and cognitive abilities. This non-invasive hypoxia model in the rat successfully and complementarily models the moderate perinatal hypoxic injury in fetuses and prematurely born human babies and may enhance future research into new diagnostic and therapeutic strategies for perinatal medicine.

Relationship between the Quantitative Indicators of Cranial MRI and the Early Neurodevelopment of Preterm Infants

Aim

To explore the relationship between the quantitative indicators (biparietal width, interhemispheric distance) of the cranial MRI for preterm infants at 37 weeks of postmenstrual age (PMA) and neurodevelopment at 6 months of corrected age.

Methods

A total of 113 preterm infants (gestational age < 37 weeks) delivered in the Obstetrics Department of the First People's Hospital of Lianyungang from September 2018 to February 2020 and directly transferred to the Neonatology Department for treatment were enrolled in this study. Based on their development quotient (DQ), the patients were divided into the normal (DQ ≥ 85, n = 76) group and the abnormal (DQ < 85, n = 37) group. Routine cranial MRI (cMRI) was performed at 37 weeks of PMA to measure the biparietal width (BPW) and interhemispheric distance (IHD). At the corrected age of 6 months, Development Screening Test (for children under six) was used to assess the participants' neurodevelopment.

Results

Univariate analysis showed statistically significant differences in BPW, IHD, and the incidence of bronchopulmonary dysplasia between the normal and the abnormal groups (P < 0.05), while no statistically significant differences were found in maternal complications and other clinical conditions between the two groups (P > 0.05). Binary logistic regression analysis demonstrated statistically significant differences in IHD and BPW between the normal and the abnormal groups (95% CI: 1.629-12.651 and 0.570-0.805, respectively; P = 0.004 and P < 0.001, respectively), while no significant differences were found in the incidence of bronchopulmonary dysplasia between the two groups (95% CI: 0.669-77.227, P = 0.104). Receiver operating characteristic curve revealed that the area under the curve of BPW, IHD, and the joint predictor (BPW + IHD) were 0.867, 0.805, and 0.881, respectively (95% CI: 0.800-0.933, 0.710-0.900, and 0.819-0.943, respectively; all P values < 0.001).

Conclusion

BPW and IHD, the two quantitative indicators acquired by cMRI, could predict the neurodevelopmental outcome of preterm infants at the corrected age of 6 months. The combination of the two indicators showed an even higher predictive value.

Structural and functional brain connectivity in moderate-late preterm infants with low-grade intraventricular hemorrhage

PURPOSE

Brain functional connectivity (FC) changes and microstructural abnormalities are reported in infants born moderate and late preterm (MLPT). We evaluated the effect of low-grade (grades I, II) intraventricular hemorrhage (IVH) in MLPT babies on brain structural connectivity (SC) and FC.

METHODS

Babies born MLPT between January 2014 and May 2017 underwent brain ultrasound (US) at 72 h and 7 days after birth, and MRI at around term equivalent. The MRI protocol comprised T1- and T2-weighted sequences, diffusion tensor imaging (DTI), and resting-state functional MRI (fMRI). SC and FC were assessed using graph analysis.

RESULTS

Of 350 MLPT neonates, 15 showed low-grade IVH on US at 72 h, for which brain MRI was available in 10. These 10 infants, with mean gestational age (GA) 34.0 ± 0.8 weeks, comprised the study group, and 10 MLPT infants of mean GA 33.9 ± 1.1 weeks, with no abnormalities on brain US and MRI, were control subjects. All study subjects presented modularity, small world topology, and rich club organization for both SC and FC. The patients with low-grade IVH had lower FC rich club coefficient and lower SC betweenness centrality in the left frontoparietal operculum, and lower SC rich club coefficient in the right superior orbitofrontal cortex than the control subjects.

CONCLUSIONS

Topological and functional properties of mature brain connectivity are present in MLPT infants. IVH in these infants was associated with structural and functional abnormalities in the left frontoparietal operculum and right orbitofrontal cortex, regions related to language and cognition.

Diffusion Tensor Imaging in Very Preterm, Moderate-Late Preterm and Term-Born Neonates: A Systematic Review

OBJECTIVE

To examine white matter abnormalities, measured by diffusion tensor imaging, in very preterm (<32 weeks) and moderate-late preterm neonates (32-37 weeks) at term-equivalent age, compared with healthy full-term controls (≥37 weeks).

STUDY DESIGN

A search of Medline (PubMed) was conducted to identify studies with diffusion data collected on very preterm, moderate-late preterm and full-term neonates, using the guidelines from the Meta-analysis of Observational Studies in Epidemiology and PRISMA statements.

RESULTS

Eleven studies were included with diffusion tensor imaging data from 554 very preterm, 575 moderate-late preterm, and 318 full-term neonates. Widespread statistically significant diffusion measures were found in all preterm subgroups at term-equivalent age compared with full-term neonates, and this difference was more marked for the very preterm group. These abnormalities are suggestive of changes in the white matter microstructure in the preterm groups. The corpus callosum was a region of interest in both early and moderate-late preterm groups, which showed statistically significant diffusion measures in all 11 studies.

CONCLUSIONS

Microstructural white matter changes may underpin the increased risk of neurodevelopmental disability seen in preterm infants in later life. diffusion tensor imaging may therefore be a useful prognostic tool for neuro-disability in preterm neonates.

Predictors of persistent and changing developmental problems of preterm children

BACKGROUND

Accurate prediction of persistent and emerging developmental problems in preterm-born children may lead to targeted interventions.

AIMS

To determine whether specific perinatal and social factors were associated with persistent, emerging, and resolving developmental problems of early-preterm (EPs) and moderately-and-late-preterm children (MLPs) from before to after school entry.

STUDY DESIGN

Observational longitudinal cohort study, part of the LOLLIPOP cohort-study.

SUBJECTS

341 EPs and 565 MLPs.

OUTCOME MEASURES

Developmental problems using the Ages and Stages Questionnaire at ages 4 and 5. We collected data on perinatal and social factors from medical records. Using logistic regression analyses we assessed associations between 48 factors and persistent, emerging, and resolving problems.

RESULTS

Of EPs, 8.7% had persistent and 5.1% emerging problems; this was 4.3% and 1.9% for MLPs, respectively. Predictors for persistent problems included chronic mental illness of the mother, odds ratio (95% confidence interval) 8.01 (1.85-34.60), male sex 4.96 (2.28-10.82), being born small-for-gestational age (SGA) 2.39 (1.15-4.99), and multiparity 3.56 (1.87-6.76). Predictors for emerging problems included MLP birth with prolonged premature rupture of membranes (PPROM) 5.01 (1.38-18.14). Including all predictors in a single prediction model, the explained variance (Nagelkerke R²) was 21.9%, whereas this was 3.0% with only EP/MLP birth as predictor.

CONCLUSIONS

Only few perinatal and social factors had associations with persistent and emerging developmental problems for both EPs and MLPs. For children with specific neonatal conditions such as SGA, and PPROM in MLPs, problems may persist. Insight in risk factors largely improved the prediction of developmental problems among preterm children.

Stability of Executive Functioning of Moderately-Late Preterm and Full-Term Born Children at Ages 11 and 19: The TRAILS Cohort Study

Moderately-late preterm-born children (MLPs, 32-36 weeks gestational age, GA) have poorer executive functioning (EF) at primary school age than full-term children (FTs). Evidence is lacking on their EF in adolescence, but for early preterm-born children, this has been shown to be much poorer. We, therefore, compared EF of MLPs and FTs at ages 11 and 19 and assessed development between these ages. We obtained data from TRAILS, a community-based prospective cohort study in the northern Netherlands, on 98 MLPs and 1832 FTs. We assessed EF by the Amsterdam Neuropsychological Tasks (ANT) at ages 11 and 19 years and computed gender-specific z-scores on reaction time and accuracy. We compared baseline speed, pattern search, working memory, sustained attention, inhibition, and attentional flexibility of MLPs and FTs crude, and adjusted for small-for-GA status, socioeconomic status, and estimated intelligence. MLPs and FTs performed similarly on all EF components at ages 11 and 19, except for the speed, but not the accuracy measure of attentional flexibility. This was slightly poorer for MLPs than FTs at age 19 (adjusted B 0.25; 95% confidence interval: 0.00 to 0.50; p = 0.047), but not at age 11 (adjusted B -0.02; -0.19 to 0.22; p = 0.87). Differences in EF between MLPs and FTs did not change significantly from age 11 to 19. MLPs had comparable EF on most components as FTs, with only attentional flexibility at age 19 developing slightly poorer for MLPs than for FTs. These findings suggest the effects of MLP birth on long-term EF to be small.

Moderately and Late Preterm Infants: Short- and Long-Term Outcomes From a Registry-Based Cohort

Background: While most studies on the association of preterm birth and cerebral palsy (CP) have focused on very preterm infants, lately, attention has been paid to moderately preterm [32 to <34 weeks gestational age (GA)] and late preterm infants (34 to <37 weeks GA).

Methods: In order to report on the outcomes of a cohort of moderately and late preterm infants, derived from a population-based CP Registry, a comparative analysis of data on 95 moderately preterm infants and 96 late preterm infants out of 1,016 with CP, was performed.

Results: Moderately preterm neonates with CP were more likely to have a history of N-ICU admission (p = 0.001) and require respiratory support (p < 0.001) than late preterm neonates. Birth weight was significantly related to early neonatal outcome with children with lower birth weight being more likely to have a history of N-ICU admission [moderately preterm infants (p = 0.006)/late preterm infants (p < 0.001)], to require ventilator support [moderately preterm infants (p = 0.025)/late preterm infants (p = 0.014)] and not to have neonatal seizures [moderately preterm infants (p = 0.044)/late preterm infants (p = 0.263)]. In both subgroups, the majority of children had bilateral spastic CP with moderately preterm infants being more likely to have bilateral spastic CP and less likely to have ataxic CP as compared to late preterm infants (p = 0.006). The prevailing imaging findings were white matter lesions in both subgroups, with statistically significant difference between moderately preterm infants who required ventilator support and mainly presented with this type of lesion vs. those who did not and presented with gray matter lesions, maldevelopments or miscellaneous findings. Gross motor function was also assessed in both subgroups without significant difference. Among late preterm infants, those who needed N-ICU admission and ventilator support as neonates achieved worse fine motor outcomes than those who did not.

Conclusions: Low birth weight is associated with early neonatal problems in both moderately and late preterm infants with CP. The majority of children had bilateral spastic CP and white matter lesions in neuroimaging. GMFCS levels were comparable in both subgroups while BFMF was worse in late preterm infants with a history of N-ICU admission and ventilator support.

Impact of moderate and late preterm birth on neurodevelopment, brain development and respiratory health at school age: protocol for a longitudinal cohort study (LaPrem study)

INTRODUCTION

Children born moderate to late preterm (MLP, 32-36 weeks' gestation) account for approximately 85% of all preterm births globally. Compared with children born at term, children born MLP are at increased risk of poor neurodevelopmental outcomes. Despite making up the largest group of preterm children, developmental outcomes of children born MLP are less well studied than in other preterm groups. This study aimed to (1) compare neurodevelopmental, respiratory health and brain magnetic resonance imaging (MRI) outcomes between children born MLP and term at 9 years of age; (2) examine the differences in brain growth trajectory from infancy to 9 years between children born MLP and term; and in children born MLP; (3) examine the relationship between brain development and neurodevelopment at 9 years; and (4) identify risk factors for poorer outcomes at 9 years.

METHODS AND ANALYSIS

The "LaPrem" (Late Preterm MRI Study) study is a longitudinal cohort study of children born MLP and term controls, born at the Royal Women's Hospital in Melbourne, Australia, between 2010 and 2013. Participants were recruited in the neonatal period and were previously followed up at 2 and 5 years. This 9-year school-age follow-up includes neuropsychology, motor and physical activities, and lung function assessments, as well as brain MRI. Outcomes at 9 years will be compared between birth groups using linear and logistic regressions. Trajectories of brain development will be compared between birth groups using mixed effects models. The relationships between MRI and neurodevelopmental outcomes, as well as other early predictors of poor 9-year outcomes, will be explored using linear and logistic regression.

ETHICS AND DISSEMINATION

This study was approved by the human research ethics committee at the Royal Children's Hospital, Melbourne, Australia. Study outcomes will be disseminated through peer-reviewed publications, conference presentations and social media.

Cognitive and Learning Outcomes in Late Preterm Infants at School Age: A Systematic Review

Late preterm children born between 34^0/7 and 36^6/7 weeks’ gestation account for ≈70% of prematurely born infants. There is growing concern about this population at risk of mild neurodevelopmental problems, learning disabilities and lower academic performance. Following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement, this paper analyzes recent published evidence from 16selected studies involving late preterm children and control group assessments at preschool and/or school age, mainly focusing on cognitive functioning, language learning and academic achievement. The review identifies the assessment tools used in these studies (standardized tests, parental questionnaires and laboratory tasks) and the areas being evaluated from preschool (age 3 years) to primary school levels. Results reveal the presence of mild difficulties, pointing to suboptimal outcomes in areas such as executive function, short term verbal memory, literacy skills, attention and processing speed. Some difficulties are transient, but others persist, possibly compromising academic achievement, as suggested by the few studies reporting on higher risk for poor school performance. Given the increasing number of late preterm children in our society the review highlights the need to implement screening strategies to facilitate early risk detection and minimize the negative effects of this morbidity in childhood.

Neonatal brain metabolite concentrations: Associations with age, sex, and developmental outcomes

Age and sex differences in brain metabolite concentrations in early life are not well understood. We examined the associations of age and sex with brain metabolite levels in healthy neonates, and investigated the associations between neonatal brain metabolite concentrations and developmental outcomes. Forty-one infants (36–42 gestational weeks at birth; 39% female) of predominantly Hispanic/Latina mothers (mean 18 years of age) underwent MRI scanning approximately two weeks after birth. Multiplanar chemical shift imaging was used to obtain voxel-wise maps of N-acetylaspartate (NAA), creatine, and choline concentrations across the brain. The Bayley Scales of Infant and Toddler Development, a measure of cognitive, language, and motor skills, and mobile conjugate reinforcement paradigm, a measure of learning and memory, were administered at 4 months of age. Findings indicated that postmenstrual age correlated positively with NAA concentrations in multiple subcortical and white matter regions. Creatine and choline concentrations showed similar but less pronounced age related increases. Females compared with males had higher metabolite levels in white matter and subcortical gray matter. Neonatal NAA concentrations were positively associated with learning and negatively associated with memory at 4 months. Age-related increases in NAA, creatine, and choline suggest rapid development of neuronal viability, cellular energy metabolism, and cell membrane turnover, respectively, during early life. Females may undergo earlier and more rapid regional developmental increases in the density of viable neurons compared to males.

Regional brain volumes, microstructure and neurodevelopment in moderate-late preterm children

OBJECTIVE

To explore whether regional brain volume and white matter microstructure at term-equivalent age (TEA) are associated with development at 2 years of age in children born moderate-late preterm (MLPT).

STUDY DESIGN

A cohort of MLPT infants had brain MRI at approximately TEA (38-44 weeks' postmenstrual age) and had a developmental assessment (Bayley Scales of Infant and Toddler Development and Infant Toddler Social Emotional Assessment) at 2 years' corrected age. Relationships between cortical grey matter and white matter volumes and 2-year developmental outcomes were explored using voxel-based morphometry. Relationships between diffusion tensor measures of white matter microstructure (fractional anisotropy (FA) and axial (AD), radial (RD) and mean (MD) diffusivities) and 2-year developmental outcomes were explored using tract-based spatial statistics.

RESULTS

189 MLPT children had data from at least one MRI modality (volumetric or diffusion) and data for at least one developmental domain. Larger cortical grey and white matter volumes in many brain regions, and higher FA and lower AD, RD and MD in several major white matter regions, were associated with better cognitive and language scores. There was little evidence that cortical grey matter and white matter volumes and white matter microstructure were associated with motor and behavioural outcomes.

CONCLUSIONS

Regional cortical grey matter and white matter volumes and white matter microstructure are associated with cognitive and language development at 2 years of age in MLPT children. Thus, early alterations to brain volumes and microstructure may contribute to some of the developmental deficits described in MLPT children.

Mental development is associated with cortical connectivity of the ventral and nonspecific thalamus of preterm newborns

INTRODUCTION

The thalamus is a key hub for regulating cortical connectivity. Dysmaturation of thalamocortical networks that accompany white matter injury has been hypothesized as neuroanatomical correlate of late life neurocognitive impairment following preterm birth. Our objective was to find a link between thalamocortical connectivity measures at term equivalent age and two-year neurodevelopmental outcome in preterm infants.

METHODS

Diffusion tensor MRI data of 58 preterm infants (postmenstrual age at birth, mean (SD), 29.71 (1.47) weeks) were used in the study. We utilized probabilistic diffusion tractography to trace connections between the cortex and thalami. Possible associations between connectivity strength, the length of the probabilistic fiber pathways, and developmental scores (Bayley Scales of Infant Development, Second Edition) were analyzed using multivariate linear regression models.

RESULTS

We found strong correlation between mental developmental index and two complementary measures of thalamocortical networks: Connectivity strength projected to a cortical skeleton and pathway length emerging from thalamic voxels (partial correlation, R = .552 and R = .535, respectively, threshold-free cluster enhancement, corrected p-value < .05), while psychomotor development was not associated with thalamocortical connectivity. Post hoc stepwise linear regression analysis revealed that parental socioeconomic scale, postmenstrual age, and the duration of mechanical ventilation at the intensive care unit contribute to the variability of outcome.

CONCLUSIONS

Our findings independently validated previous observations in preterm infants, providing additional evidence injury or dysmaturation of tracts emerging from ventral-specific and various nonspecific thalamus projecting to late-maturing cortical regions are predictive of mental, but not psychomotor developmental outcomes.

A systematic review on brain injury and altered brain development in moderate-late preterm infants

OBJECTIVES

To provide a systematic review of brain injury and altered brain development in moderate-late preterm (MLPT) infants as compared to very preterm and term infants.

STUDY DESIGN

A systematic search in five databases was performed in January 2020. Original research papers on incidence of brain injury and papers using quantitative data on brain development in MLPT infants were selected. The Johanna Briggs Institute 'Critical Appraisal Checklist for Studies Reporting Prevalence Data' was used for quality appraisal. Data extraction included: imaging modality, incidences of brain injury, brain volumes, 2D-measurements and diffusivity values.

RESULTS

In total, 24 studies were eligible. Most studies had a moderate quality. Twenty studies reported on the incidence of brain injury in MLPT infants. The incidence of intraventricular hemorrhage (IVH) ranged from 0.0% to 23.5% and of white matter injury (WMI) from 0.5% to 10.8%. One study reported the incidence of arterial infarction (0.3%) and none of cerebellar hemorrhage. Eleven studies compared incidences of brain injury between MLPT infants and very preterm or term infants. Five studies reported signs of altered brain development in MLPT infants.

CONCLUSIONS

The incidences of IVH and WMI in MLPT infants varied widely between studies. Other abnormalities were sparsely reported. Evidence regarding a higher or lower incidence of brain injury in MLPT infants compared to very preterm or term infants is weak due to moderate methodological quality of reported studies. There is limited evidence suggesting a difference in brain development between MLPT and term infants.

Late preterm infants - Changing trends and continuing challenges

Late preterm infants, defined as newborns born between 340/7-366/7 weeks of gestational age, constitute a unique group among all premature neonates. Often overlooked because of their size when compared to very premature infants, this population is still vulnerable because of physiological and structural immaturity. Comprising nearly 75% of babies born less than 37 weeks of gestation, late preterm infants are at increased risk for morbidities involving nearly every organ system as well as higher risk of mortality when compared to term neonates. Neurodevelopmental impairment has especially been a concern for these infants. Due to various reasons, the rate of late preterm births continue to rise worldwide. Caring for this high risk population contributes a significant financial burden to health systems. This article reviews recent trends in regarding rate of late preterm births, common morbidities and long term outcomes with special attention to neurodevelopmental outcomes.

Relationship between moderate to late preterm, diet types and developmental delay in less-developed rural China

Aim: To measure the development of moderate to late preterm children by Ages and Stages Questionnaires (ASQ) and explore the relationship between moderate to late preterm, diet types and development delay in less-developed rural China.Methods: Data were collected from a cross-sectional community-based survey, which recruited 1748 children aged 1-59 months in eight counties of China. Caregivers of these children completed the Chinese version of ASQ-3 (ASQ-C) while physical examination and questionnaires on socio-demographic characteristics were conducted. Multivariate logistic regressions were used to analyze the association between moderate to late preterm and suspected developmental delay, as well as the association between diet types and suspected developmental delay. Consumption of certain food types was compared between moderate to late preterm and full-term children.Results: The prevalence of suspected overall developmental delay was 31.3% in the moderate to the late preterm group, compared with 21.6% in the full-term group. Moderate to late preterm birth was not associated with total suspected developmental delay and developmental delay in all the domains of ASQ, except for fine motor (OR = 2.43 95% C.I.: 1.04-5.56). The intake of vegetables and fruits had a protective influence on developmental delay in fine motor function, and moderate to late preterm children had lower relative consumption of fruits and vegetables than full-term children.Conclusion: Moderate to late preterm children in rural China showed an increased likelihood of developmental delay in fine motor function. Future interventions to improve the intake of vegetables and fruits in moderate to late preterm children are recommended.

Assessment of the executive functions of moderate preterm children in preschool age

This study assesses EF and socioemotional development in 30 MPT children between 4 and 6 years, comparing them with 31 FT children. Working Memory was assessed with Digit Span and Corsi Block, verbal inhibitory control and cognitive flexibility with The Shape School Test, visuomotor inhibition with Go/No-Go and socioemotional development with SDQ for parents. In our study, MPT preschoolers had a poorer working memory, inhibitory control and verbal cognitive flexibility, and more emotional problems compared. Our results suggest that there is no safe gestational age in prematurity, for this reason, EF of preterm children should be evaluated at an early age, so early intervention plans can be implemented, preventing preterm from entering primary education in disadvantage.

Feasibility of fast brain diffusion MRI to quantify white matter injury in pediatric hydrocephalus

OBJECTIVE

Traditionally, diffusion MRI (dMRI) has been performed in parallel with high-resolution conventional MRI, which requires long scan times and may require sedation or general anesthesia in infants and young children. Conversely, fast brain MRI permits image acquisition without the need for sedation, although its short pulse sequences, susceptibility to motion artifact, and contrast resolution have limited its use to assessing ventricular size or major structural variations. Here, the authors demonstrate the feasibility of leveraging a 3-direction fast brain MRI protocol to obtain reliable dMRI measures.

METHODS

Fast brain MRI with 3-direction dMRI was performed in infants and children before and after hydrocephalus treatment. Regions of interest in the posterior limbs of the internal capsules (PLICs) and the genu of the corpus callosum (gCC) were drawn on diffusion-weighted images, and mean diffusivity (MD) data were extracted. Ventricular size was determined by the frontal occipital horn ratio (FOHR). Differences between and within groups pre- and posttreatment, and FOHR-MD correlations were assessed.

RESULTS

Of 40 patients who met inclusion criteria (median age 27.5 months), 15 (37.5%), 17 (42.5%), and 8 (20.0%) had posthemorrhagic hydrocephalus (PHH), congenital hydrocephalus (CH), or no intracranial abnormality (controls), respectively. A hydrocephalus group included both PHH and CH patients. Prior to treatment, the FOHR (p < 0.001) and PLIC MD (p = 0.027) were greater in the hydrocephalus group than in the controls. While the mean gCC MD in the hydrocephalus group (1.10 × 10-3 mm2/sec) was higher than that of the control group (0.98), the difference was not significant (p = 0.135). Following a median follow-up duration of 14 months, decreases in FOHR, PLIC MD, and gCC MD were observed in the hydrocephalus group and were similar to those in the control group (p = 0.107, p = 0.702, and p = 0.169, respectively). There were no correlations identified between FOHR and MDs at either time point.

CONCLUSIONS

The utility of fast brain MRI can be extended beyond anatomical assessments to obtain dMRI measures. A reduction in PLIC and gCC MD to levels similar to those of controls was observed within 14 months following shunt surgery for hydrocephalus in PHH and CH infants. Further studies are required to assess the role of fast brain dMRI for assessing clinical outcomes in pediatric hydrocephalus patients.

Brain structure and neurological and behavioural functioning in infants born preterm

AIM

To examine: (1) relationships between brain structure, and concurrently assessed neurological and behavioural functioning, in infants born preterm at term-equivalent age (TEA; approximately 38-44wks); and (2) whether brain structure-function relationships differ between infants born very (24-29wks) and moderate-late (32-36wks) preterm.

METHOD

A total of 257 infants (91 very preterm, 166 moderate-late preterm; 120 males, 137 females) had structural magnetic resonance imaging (MRI) and neurological and behavioural assessments (Prechtl's general movements assessment, Neonatal Intensive Care Unit Network Neurobehavioral Scale [NNNS] and Hammersmith Neonatal Neurological Examination [HNNE]). Two hundred and sixty-three infants (90 very preterm, 173 moderate-late preterm; 131 males, 132 females) had diffusion MRI and assessments. Associations were investigated between assessment scores and global brain volumes using linear regressions, regional brain volumes using Voxel-Based Morphometry, and white matter microstructure using Tract-Based Spatial Statistics.

RESULTS

Suboptimal scores on some assessments were associated with lower fractional anisotropy and/or higher axial, radial, and mean diffusivities in some tracts: NNNS attention and reflexes, and HNNE total score and tone, were associated with the corpus callosum and optic radiation; NNNS quality of movement with the corona radiata; HNNE abnormal signs with several major tracts. Brain structure-function associations generally did not differ between the very and moderate-late preterm groups.

INTERPRETATION

White matter microstructural alterations may be associated with suboptimal neurological and behavioural performance in some domains at TEA in infants born preterm. Brain structure-function relationships are similar for infants born very preterm and moderate-late preterm.

WHAT THIS PAPER ADDS

Brain volume is not related to neurological/behavioural function in infants born preterm at term. White matter microstructure is related to some neurological/behavioural domains at term. Brain-behaviour relationships are generally similar for infants born very preterm and moderate-late preterm.

Does intra-uterine language experience modulate word stress processing? An ERP study

BACKGROUND

Preterm birth is associated with various risks, including delayed or atypical language development. The prenatal start of prosodic tuning may affect the processing of word stress, an important suprasegmental feature of spoken utterances.

AIM

Our study focused on the expected contribution of intra-uterine experience to word stress processing. We aimed to demonstrate the hypothesized effect of intra-uterine sound exposition on stress sensitivity.

METHOD

We recorded ERP responses of 34 preterm infants elicited by bisyllabic pseudo-words in two oddball conditions by switching the stress pattern (legal vs. illegal) and role (standard vs. deviant).

RESULTS

The mismatch responses found were synchronized to each syllable of the illegally stressed stimuli with no difference between pre- and full-term infants. However, the clear role of the preterm status was demonstrated by the exaggerated processing of the native stress information. The impact of intra-uterine exposure to prosody was confirmed by our finding that moderate-late preterm infants outperformed the very preterm ones.

CONCLUSION

Intra-uterine exposition to prosodic features appears to contribute to the emergence of stable long-term stress representation. When this tuning is missing it is considered a risk for the language acquisition process.

Associations of gestational age and birth anthropometric indicators with brain white matter maturation in full-term neonates

Newborn assessments, including gestational age (GA) and anthropometric measurements (birth weight, crown-heel length, head circumference) are routinely performed in pediatric settings, being used as important indicators in assessing neonatal development. Close associations of these birth indicators with later cognitive abilities were also reported. However, specific associations of these indicators with white matter (WM) development during the neonatal period remain unclear, as well as the extent to which they influence WM maturation. To address this issue, 51 full-term neonates (GA range, 37-42 weeks) with no abnormalities on MRI were retrospectively recruited. Specific correlations between birth indicators and WM maturation, quantified by diffusion tensor imaging (DTI)-metrics (fractional anisotropy, mean diffusivity, axial diffusivity, radial diffusivity), were identified by using DTI tract-based spatial statistics and automated fiber-tract quantification. Our findings suggest that (a) higher GA, birth weight, and crown-heel length may indicate greater WM maturation in full-term neonates, while head circumference presented weak correlation with WM maturation during early newborn period; (b) among the four indicators examined, GA was the one most associated with WM maturation. We believe that this study advances our knowledge of specific correlations between birth indicators and neonatal brain development and provides a valuable reference for future neonatal studies.

Late preterm births: New insights from neonatal neuroimaging and neurobehaviour

With increasing evidence of neurodevelopmental problems faced by late preterm children, there is a need to explore possible underlying brain structural changes. The use of brain magnetic resonance imaging has provided insights of smaller and less mature brains in infants born late preterm, associated with developmental delay at 2 years. Another useful tool in the newborn period is neurobehavioural assessment, which has also been shown to be suboptimal in late preterm infants compared with tern infants. Suboptimal neurobehaviour is also associated with poorer 2-year neurodevelopment in late preterm infants. More research into these tools will provide a better understanding of the underlying processes of developmental deficits of late preterm children. The value of their role in clinical care remains to be determined.

Longitudinal growth and emotional and behavioral problems at age 7 in moderate and late preterms

Objectives

Moderately and late preterm children (MLPs, 32.0–36.9 weeks gestational age) have a greater risk of poorer growth. This seems to be associated with poorer neuropsychological functioning. Evidence is limited on whether this also holds for emotional and behavioral (EB) problems. Therefore, we assessed whether longitudinal growth from birth until age 7 was associated with EB problems at age 7 in MLPs.

Study design

This study was part of the Longitudinal Preterm Outcome Project, a prospective cohort study. Data on growth (height, weight, head circumference, and extent of catch-up growth) were obtained from assessments from birth until age 7. EB problems were assessed at age 7 with the Child Behavior Checklist. We assessed whether growth and EB problems were associated using logistic regression analyses, adjusting for multiple birth, parity, and socioeconomic status.

Results

We included 248 MLPs. Median gestational age was 34 weeks (interquartile range: 33–35 weeks). Mean birth weight was 2.2 kg (standard deviation: 0.5 kg). Postnatal growth measures were below the Dutch reference norm. EB problems were more prevalent in MLPs than in the general Dutch population. Generally, we found no associations between growth and EB problems; odds ratios ranged from 0.20 to 2.72.

Conclusions

In MLPs, postnatal growth from birth until age 7 was not associated with EB problems at age 7. Poorer growth thus seems to relate to neuropsychological problems, but not to EB problems. This suggests that the etiologies of these problems differ at least partially.

Birth and Neonatal Transition in the Guinea Pig: Experimental Approaches to Prevent Preterm Birth and Protect the Premature Fetus

The guinea pig (Cavia porcellus) displays many features of gestational physiology that makes it the most translationally relevant rodent species. Progesterone production undergoes a luteal to placental shift as in human pregnancy with levels rising during gestation and with labor and delivery occurring without a precipitous decline in maternal progesterone levels. In contrast to other laboratory rodents, labor in guinea pigs is triggered by a functional progesterone withdrawal, which involves the loss of uterine sensitivity to progesterone like in women. In both species the amnion membrane is a major source of labor-inducing prostaglandins, which promote functional progesterone withdrawal by modifying myometrial progesterone receptor expression. These similar features appear to result from convergent evolution rather than closer evolutionally relationship to primates compared to other rodents. Nevertheless, the similarities in the production, metabolism and actions of progesterone and prostaglandins allow information gained in pregnant guinea pigs to be extended to pregnant women with confidence. This includes exploring the effects of pregnancy complications including growth restriction and the mechanisms by which stressful conditions increase the incidence of preterm labor. The relatively long gestation of the guinea pig and the maturity of the pups at birth particularly in brain development means that a greater proportion of brain development happens in utero. This allows adverse intrauterine conditions to make a sustained impact on the developing brain like in compromised human pregnancies. In addition, the brain is exposed to a protective neurosteroid environment in utero, which has been suggested to promote development in the guinea pig and the human. Moreover, in utero stresses that have been shown to adversely affect long term neurobehavioral outcomes in clinical studies, can be modeled successfully in guinea pigs. Overall, these parallels to the human have led to increasing interest in the guinea pig for translational studies of treatments and therapies that potentially improve outcomes following adverse events in pregnancy and after preterm birth.

Characterisation of brain volume and microstructure at term-equivalent age in infants born across the gestational age spectrum

BACKGROUND

Risk of morbidity differs between very preterm (VP; <32 weeks' gestational age (GA)), moderate preterm (MP; 32-33 weeks' GA), late preterm (LP; 34-36 weeks' GA), and full-term (FT; ≥37 weeks' GA) infants. However, brain structure at term-equivalent age (TEA; 38-44 weeks) remains to be characterised in all clinically important GA groups. We aimed to compare global and regional brain volumes, and regional white matter microstructure, between VP, MP, LP and FT groups at TEA, in order to establish the magnitude and anatomical locations of between-group differences.

METHODS

Structural images from 328 infants (91 VP, 63 MP, 104 LP and 70 FT) were segmented into white matter, cortical grey matter, cerebrospinal fluid (CSF), subcortical grey matter, brainstem and cerebellum. Global tissue volumes were analysed, and additionally, cortical grey matter and white matter volumes were analysed at the regional level using voxel-based morphometry. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) images from 361 infants (92 VP, 69 MP, 120 LP and 80 FT) were analysed using Tract-Based Spatial Statistics. Statistical analyses involved examining the overall effect of GA group on global volumes (using linear regressions) and regional volumes and microstructure (using non-parametric permutation testing), as well performing post-hoc comparisons between the GA sub-groups.

RESULTS

On global analysis, cerebrospinal fluid (CSF) volume was larger in all preterm sub-groups compared with the FT group. On regional analysis, volume was smaller in parts of the temporal cortical grey matter, and parts of the temporal white matter and corpus callosum, in all preterm sub-groups compared with the FT group. FA was lower, and RD and MD were higher in voxels located in much of the white matter in all preterm sub-groups compared with the FT group. The anatomical locations of group differences were similar for each preterm vs. FT comparison, but the magnitude and spatial extent of group differences was largest for the VP, followed by the MP, and then the LP comparison. Comparing within the preterm groups, the VP sub-group had smaller frontal and temporal grey and white matter volume, and lower FA and higher MD and RD within voxels in the approximate location of the corpus callosum compared with the MP sub-group. There were few volume and microstructural differences between the MP and LP sub-groups.

CONCLUSION

All preterm sub-groups had atypical brain volume and microstructure at TEA when compared with a FT group, particularly for the CSF, temporal grey and white matter, and corpus callosum. In general, the groups followed a gradient, where the differences were most pronounced for the VP group, less pronounced for the MP group, and least pronounced for the LP group. The VP sub-group was particularly vulnerable compared with the MP and LP sub-groups.

Individual differences in ERP measures of executive function in early childhood: Relation to low-risk preterm birth and parent-reported behavior

Although behavioral studies have demonstrated that executive function (EF) develops rapidly during early childhood, few studies have investigated neural systems supporting EF during the preschool years. These systems are sensitive to variations in children's early life experiences, including preterm birth. The current study collected behavioral and event related potential (ERP) data during an EF task (directional Stroop) in a sample of 150 full-term and low-risk preterm children aged 4-years. Children's IQ and processing speed (WPPSI-III), and parent report of EF (BRIEF-P), were also measured. Forty-nine children born full-term and 43 low-risk preterm children provided useable ERP data. Similar to prior studies with adults and older children, preschool-aged children showed modulation of ERP components (N2, P3) by cognitive conflict. Effects of trial type were also present for early attentional components (N1 and P2). Exploratory analyses demonstrated that ERP measures of EF were correlated with individual differences in cognitive and behavioral functioning in both full-term and low-risk preterm populations. Future research investigating the neural correlates of early measures of EF in low-risk preterm children and other at-risk groups is warranted to better understand how trajectories of EF development are altered in the first years of life.

Rapid Infant Prefrontal Cortex Development and Sensitivity to Early Environmental Experience

Over the last fifteen years, the emerging field of developmental cognitive neuroscience has described the relatively late development of prefrontal cortex in children and the relation between gradual structural changes and children's protracted development of prefrontal-dependent skills. Widespread recognition by the broader scientific community of the extended development of prefrontal cortex has led to the overwhelming perception of prefrontal cortex as a "late developing" region of the brain. However, despite its supposedly protracted development, multiple lines of research have converged to suggest that prefrontal cortex development may be particularly susceptible to individual differences in children's early environments. Recent studies demonstrate that the impacts of early adverse environments on prefrontal cortex are present very early in development: within the first year of life. This review provides a comprehensive overview of new neuroimaging evidence demonstrating that prefrontal cortex should be characterized as a "rapidly developing" region of the brain, discusses the converging impacts of early adversity on prefrontal circuits, and presents potential mechanisms via which adverse environments shape both concurrent and long-term measures of prefrontal cortex development. Given that environmentally-induced disparities are present in prefrontal cortex development within the first year of life, translational work in intervention and/or prevention science should focus on intervening early in development to take advantages of this early period of rapid prefrontal development and heightened plasticity.

17OHP-C in patients with spontaneous preterm labor and intact membranes: is there an effect according to the presence of intra-amniotic inflammation?

PROBLEM

It is not known whether 17-alpha-hydroxyprogesterone caproate (17OHP-C) is effective for preventing preterm delivery with an episode of preterm labor (PTL) with or without intra-amniotic inflammation/infection.

METHODS OF STUDY

This was a retrospective cohort study. One hundred and seven PTL patients were selected and divided into a 17OHP-C group (use of 17OHP-C: n = 53) and a no-treatment group (no use of 17OHP-C: n = 54). Moreover, the patients were divided into three subgroups (subgroup A: without intra-amniotic inflammation, B: with mild intra-amniotic inflammation, and C: with severe intra-amniotic inflammation) according to their level of amniotic interleukin (IL)-8, and perinatal prognosis was analyzed.

RESULTS

Interval from admission to delivery (days) in the 17OHP-C group (76 [13-126], n = 34) was significantly longer than that in the no-treatment group (50 [8-104], n = 33; P = .012) in subgroup B. In cases without intra-amniotic microbes in subgroup B, a significant prolongation of gestational days was associated with the 17OHP-C group (79 [13-126], n = 25) compared with the no-treatment group (50 [8-104], n = 29; P = .029). However, there were no significant differences in subgroups A or C.

CONCLUSION

17OHP-C could prolong gestational period in limited PTL cases with sterile mild intra-amniotic inflammation.

Antecedents and Outcomes of Abnormal Cranial Imaging in Moderately Preterm Infants

OBJECTIVES

To describe the frequency and findings of cranial imaging in moderately preterm infants (born at 290/7-336/7 weeks of gestation) across centers, and to examine the association between abnormal imaging and clinical characteristics.

STUDY DESIGN

We used data from the Neonatal Research Network Moderately Preterm Registry, including the most severe early (≤28 days) and late (>28 days) cranial imaging. Stepwise logistic regression and CART analysis were performed after adjustment for gestational age, antenatal steroid use, and center.

RESULTS

Among 7021 infants, 4184 (60%) underwent cranial imaging. These infants had lower gestational ages and birth weights and higher rates of small for gestational age, outborn birth, cesarean delivery, neonatal resuscitation, and treatment with surfactant, compared with those without imaging (P < .0001). Imaging abnormalities noted in 15% of the infants included any intracranial hemorrhage (13.2%), grades 3-4 intracranial hemorrhage (1.7%), cystic periventricular leukomalacia (2.6%), and ventriculomegaly (6.6%). Histologic chorioamnionitis (OR, 1.47; 95% CI, 1.19-1.83), gestational age (0.95; 95% CI, 0.94-0.97), antenatal steroids (OR, 0.55; 95% CI, 0.41-0.74), and cesarean delivery (OR, 0.66; 95% CI, 0.53-0.81) were associated with abnormal imaging. The center with the highest rate of cranial imaging, compared with the lowest, had a higher risk of abnormal imaging (OR, 2.08; 95% CI, 1.10-3.92). On the classification and regression-tree model, cesarean delivery, center, antenatal steroids, and chorioamnionitis, in that order, predicted abnormal imaging.

CONCLUSION

Among the 60% of moderately preterm infants with cranial imaging, 15% had intracranial hemorrhage, cystic periventricular leukomalacia or late ventriculomegaly. Further correlation of imaging and long-term neurodevelopmental outcomes in moderately preterm infants is needed.

Gestational Age at Birth and Brain White Matter Development in Term-Born Infants and Children

BACKGROUND AND PURPOSE

Studies on infants and children born preterm have shown that adequate gestational length is critical for brain white matter development. Less is known regarding how variations in gestational age at birth in term infants and children affect white matter development, which was evaluated in this study.

MATERIALS AND METHODS

Using DTI tract-based spatial statistics methods, we evaluated white matter microstructures in 2 groups of term-born (≥37 weeks of gestation) healthy subjects: 2-week-old infants (n = 44) and 8-year-old children (n = 63). DTI parameters including fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity were calculated by voxelwise and ROI methods and were correlated with gestational age at birth, with potential confounding factors such as postnatal age and sex controlled.

RESULTS

Fractional anisotropy values, which are markers for white matter microstructural integrity, positively correlated (P < .05, corrected) with gestational age at birth in most major white matter tracts/regions for the term infants. Mean diffusivity values, which are measures of water diffusivities in the brain, and axial and radial diffusivity values, which are markers for axonal growth and myelination, respectively, negatively correlated (P < .05, corrected) with gestational age at birth in all major white matter tracts/regions excluding the body and splenium of the corpus callosum for the term infants. No significant correlations with gestational age were observed for any tracts/regions for the term-born 8-year-old children.

CONCLUSIONS

Our results indicate that longer gestation during the normal term period is associated with significantly greater infant white matter development (as reflected by higher fractional anisotropy and lower mean diffusivity, axial diffusivity, and radial diffusivity values); however, similar associations were not observable in later childhood.

A quantitative method for microstructural analysis of myelinated axons in the injured rodent brain

MRI studies (e.g. using diffusion tensor imaging) revealed that injury to white matter tracts, as observed in for instance perinatal white matter injury and multiple sclerosis, leads to compromised microstructure of myelinated axonal tracts. Alterations in white matter microstructure are also present in a wide range of neurological disorders including autism-spectrum disorders, schizophrenia and ADHD. Whereas currently myelin quantity measures are often used in translational animal models of white matter disease, it can be an important valuable addition to study the microstructural organization of myelination patterns in greater detail. Here, we describe methods to extensively study the microstructure of cortical myelination by immunostaining for myelin. To validate these methods, we carefully analyzed the organization of myelinated axons running from the external capsule towards the outer layers of the cortex in three rodent models of neonatal brain injury and in an adult stroke model, that have all been associated with myelination impairments. This unique, relatively easy and sensitive methodology can be applied to study subtle differences in myelination patterns in animal models in which aberrations in myelination integrity are suspected. Importantly, the described methods can be applied to determine efficacy of novel experimental treatments on microstructural organization of cortical myelination.

[Late preterm infants in Spain: Experience of the 34-36 Neonatal Group]

INTRODUCTION

Late preterm (LP) infants (34 -36 weeks of gestation) are the largest group of preterm infants and also the least studied so far. In order to improve their care and reduce the impact of their increased morbidity and mortality, it is essential to know the current situation in Spain.

POPULATION AND METHOD

Clinical-epidemiological variables of the LP population of 34 participating hospitals were prospectively collected from 1 April 2011 to 31 March 2016, and were then compared with the Minimum Perinatal Data Set for term births in the database.

RESULTS

Of the 9,121 LP studied, 21.7% of 34, 30.8% of 35, and 47.5% of 36 weeks of gestation. The mortality rate was 2.8%. More than one-quarter (27.7%) were multiple pregnancies. Maternal disease were identified in 47.1% and 41.4% were pathological gestation. Just under half (47.9%) were by Caesarean section and 18.8% were of unknown origin or unjustified. No known cause of prematurity was found in 29%, and 3.1% were recognized as unjustified?caesarean?. Just under half (47%) of the LP were breastfed, and 58.6% required admission to neonatology, with 15.2% to Neonatal Intensive Care Unit. Coded diagnoses were recorded in 46.2%, with the most frequent being jaundice, 43.5%, hypoglycaemia, 30%, and respiratory disorders with 28.7%.

CONCLUSIONS

The large sample of LP studied helps us to highlight the higher neonatal mortality and morbidity that this population suffers and the unavoidable relationship of its incidence with multiparity, maternal aging, and the still numerous inductions of labour and unjustified elective caesareans.

Functional neural bases of numerosity judgments in healthy adults born preterm

High rates of mathematics learning disabilities among individuals born preterm (<37weeksGA) have spurred calls for a greater understanding of the nature of these weaknesses and their neural underpinnings. Groups of healthy, high functioning young adults born preterm and full term (n=20) completed a symbolic and non-symbolic magnitude comparison task while undergoing functional MRI scanning. Collectively, participants showed activation in superior and inferior frontal and parietal regions previously linked to numeric processing when comparing non-symbolic magnitude arrays separated by small numeric distances. Simultaneous deactivation of the default mode network also was evident during these trials. Individuals born preterm showed increased signal change relative to their full term peers in right inferior frontal and parietal regions when comparing the non-symbolic magnitude arrays. Elevated signal change during non-symbolic task blocks was associated with poorer performance on a calculation task administered outside of the scanner. These findings indicate that healthy, high-functioning adults born preterm may recruit fronto-parietal networks more extensively when processing non-symbolic magnitudes, suggesting that approximate number system training may be an inroad for early intervention to prevent mathematics difficulties in this population.