Deep grey matter growth predicts neurodevelopmental outcomes in very preterm children

Subcortical Brain Volumes and Neurocognitive Function in Children With Perinatal HIV Exposure: A Population-Based Cohort Study in South Africa

Background

Children who are HIV-exposed and uninfected (HEU) are at risk for early neurodevelopmental impairment. Smaller basal ganglia nuclei have been reported in neonates who are HEU compared to HIV-unexposed (HU); however, neuroimaging studies outside infancy are scarce. We examined subcortical brain structures and associations with neurocognition in children who are HEU.

Methods

This neuroimaging study was nested within the Drakenstein Child Health Study birth cohort in South Africa. We compared (T1-weighted) magnetic resonance imaging-derived subcortical brain volumes between children who were HEU (n = 70) and HU (n = 92) at age 2-3 years using linear regression. Brain volumes were correlated with neurodevelopmental outcomes measured with the Bayley Scales of Infant and Toddler Development III.

Results

Compared to HU children, on average children who were HEU had 3% lower subcortical grey matter volumes. Analyses of individual structures found smaller volume of the putamen nucleus in the basal ganglia (-5% difference, P = .016) and the hippocampus (-3% difference, P = .044), which held on adjustment for potential confounders (P < .05). Maternal viremia and lower CD4 count in pregnancy were associated with smaller child putamen volumes. Children who were HEU had lower language scores than HU; putamen and hippocampus volumes were positively correlated with language outcomes.

Conclusions

Overall, children who are HEU had a pattern of smaller subcortical volumes in the basal ganglia and hippocampal regions compared to HU children, which correlated with language function. Findings suggest that optimizing maternal perinatal HIV care is important for child brain development. Further studies are needed to investigate underlying mechanisms and long-term outcomes.

Cognitive outcome and its neural correlates after cardiorespiratory arrest in childhood

Hypoxia-ischaemia (HI) can result in structural brain abnormalities, which in turn can lead to behavioural deficits in various cognitive and motor domains, in both adult and paediatric populations. Cardiorespiratory arrest (CA) is a major cause of hypoxia-ischaemia in adults, but it is relatively rare in infants and children. While the effects of adult CA on brain and cognition have been widely studied, to date, there are no studies examining the neurodevelopmental outcome of children who suffered CA early in life. Here, we studied the long-term outcome of 28 children who suffered early CA (i.e., before age 16). They were compared to a group of control participants (n = 28) matched for age, sex and socio-economic status. The patient group had impairments in the domains of memory, language and academic attainment (measured using standardised tests). Individual scores within the impaired range were most commonly found within the memory domain (79%), followed by academic attainment (50%), and language (36%). The patient group also had reduced whole brain grey matter volume, and reduced volume and fractional anisotropy of the white matter. In addition, lower performance on memory tests was correlated with bilaterally reduced volume of the hippocampi, thalami, and striatum, while lower attainment scores were correlated with bilateral reduction of fractional anisotropy in the superior cerebellar peduncle, the main output tract of the cerebellum. We conclude that patients who suffered early CA are at risk of developing specific cognitive deficits associated with structural brain abnormalities. RESEARCH HIGHLIGHTS: Our data shed light on the long-term outcome and associated neural mechanisms after paediatric hypoxia-ischaemia as a result of cardiorespiratory arrest. Patients had impaired scores on memory, language and academic attainment. Memory impairments were associated with smaller hippocampi, thalami, and striatum. Lower academic attainment correlated with reduced fractional anisotropy of the superior cerebellar peduncle.

Pain Exposure and Brain Connectivity in Preterm Infants

Importance

Early-life exposure to painful procedures has been associated with altered brain maturation and neurodevelopmental outcomes in preterm infants, although sex-specific differences are largely unknown.

Objective

To examine sex-specific associations among early-life pain exposure, alterations in neonatal structural connectivity, and 18-month neurodevelopment in preterm infants.

Design, Setting, and Participants

This prospective cohort study recruited 193 very preterm infants from April 1, 2015, to April 1, 2019, across 2 tertiary neonatal intensive care units in Toronto, Canada. Structural connectivity data were available for 150 infants; neurodevelopmental outcomes were available for 123 infants. Data were analyzed from January 1, 2022, to December 31, 2023.

Exposure

Pain was quantified in the initial weeks after birth as the total number of invasive procedures.

Main Outcome and Measure

Infants underwent early-life and/or term-equivalent-age magnetic resonance imaging with diffusion tensor imaging to quantify structural connectivity using graph theory measures and regional connection strength. Eighteen-month neurodevelopmental outcomes were assessed with the Bayley Scales of Infant and Toddler Development, Third Edition. Stratifying by sex, generalized estimating equations were used to assess whether pain exposure modified the maturation of structural connectivity using an interaction term (early-life pain exposure × postmenstrual age [PMA] at scan). Generalized estimating equations were used to assess associations between structural connectivity and neurodevelopmental outcomes, adjusting for extreme prematurity and maternal education.

Results

A total of 150 infants (80 [53%] male; median [IQR] gestational age at birth, 27.1 [25.4-29.0] weeks) with structural connectivity data were analyzed. Sex-specific associations were found between early-life pain and neonatal brain connectivity in female infants only, with greater early-life pain exposure associated with slower maturation in global efficiency (pain × PMA at scan interaction P = .002) and local efficiency (pain × PMA at scan interaction P = .005). In the full cohort, greater pain exposure was associated with lower global efficiency (coefficient, -0.46; 95% CI, -0.78, to -0.15; P = .004) and local efficiency (coefficient, -0.57; 95% CI, -1.04 to -0.10; P = .02) and regional connection strength. Local efficiency (coefficient, 0.003; 95% CI, 0.001-0.004; P = .005) and regional connection strength in the striatum were associated with cognitive outcomes.

Conclusions and Relevance

In this cohort study of very preterm infants, greater exposure to early-life pain was associated with altered maturation of neonatal structural connectivity, particularly in female infants. Alterations in structural connectivity were associated with neurodevelopmental outcomes, with potential regional specificities.

Neurodevelopmental Correlates of Brain Magnetic Resonance Imaging Abnormalities in Extremely Low-birth-weight Infants

OBJECTIVE

To evaluate the relationship between impaired brain growth and structural brain abnormalities at term-equivalent age (TEA) and neurodevelopment in extremely low-birth-weight (ELBW) infants over the first 2 years.

METHODS

ELBW infants born from 2009 through 2018 and undergoing brain magnetic resonance imaging (MRI) at TEA were enrolled in this retrospective cohort study. MRI scans were reviewed using a validated quali-quantitative score, including several white and gray matter items. Neurodevelopment was assessed at 6, 12, 18, and 24 months using the Griffiths scales. The independent associations between MRI subscores and the trajectories of general and specific neurodevelopmental functions were analyzed by generalized estimating equations.

RESULTS

One hundred-nine ELBW infants were included. White matter volume reduction and delayed myelination were associated with worse general development (b = -2.33, P = .040; b = -6.88, P = .049 respectively), social skills (b = -3.13, P = .019; b = -4.79, P = .049), and eye-hand coordination (b = -3.48, P = .009; b = -7.21, P = .045). Cystic white matter lesions were associated with poorer motor outcomes (b = -4.99, P = .027), while white matter signal abnormalities and corpus callosum thinning were associated with worse nonverbal cognitive performances (b = -6.42, P = .010; b = -6.72, P = .021, respectively). Deep gray matter volume reduction correlated with worse developmental trajectories.

CONCLUSIONS

Distinctive MRI abnormalities correlate with specific later developmental skills. This finding may suggest that TEA brain MRI may assist with neurodevelopmental prediction, counseling of families, and development of targeted supportive interventions to improve neurodevelopment in ELBW neonates.

Relationship between early nutrition and deep gray matter and lateral ventricular volumes of preterm infants at term-equivalent age

BACKGROUND

The survival of preterm infants has improved over the last decade, but impaired brain development leading to poor neurological outcomes is still a major comorbidity associated with prematurity. The aim of this study was to evaluate the effect of nutrition on neurodevelopment in preterm infants and identify markers for improved outcomes.

METHODS

Totally 67 premature infants with a gestational age of 24-34 weeks and a birth weight of 450-2085 g were included. Clinical parameters and documented diet were collected from medical records. The nutritional analysis comprised the protein, fat, carbohydrate, and energy intake during different time spans. Brain development was assessed by determining deep gray matter (DGM; basal ganglia and thalamus) and lateral ventricular (LV) volumes as measured on cerebral magnetic resonance imaging scans obtained at term-equivalent age (TEA), and potential associations between nutrition and brain volumetrics were detected by regression analysis.

RESULTS

We observed a negative correlation between mean daily protein intake in the third postnatal week and MRI-measured DGM volume at TEA (P = 0.007). In contrast, head circumference at a corrected age of 35 weeks gestation (P < 0.001) and mean daily fat intake in the fourth postnatal week (P = 0.004) were positively correlated with DGM volume. Moreover, mean daily carbohydrate intake in the first postnatal week (P = 0.010) and intraventricular hemorrhage (P = 0.003) were revealed as independent predictors of LV volume.

CONCLUSION

The study emphasizes the importance of nutrition for brain development following preterm birth.

The Pull-to-Sit Task: Examining Infant Postural Development in Autism Spectrum Disorder

OBJECTIVE

To evaluate the predictive relationship between early trajectories of postural and head control during a pull-to-sit task and later autism diagnostic and developmental outcomes.

STUDY DESIGN

Using a prospective longitudinal design, postural skills of 100 infants at elevated and low familial likelihood of autism spectrum disorder (ASD) were evaluated using a pull-to-sit task monthly from age 1 month to 6 months. At age 24 months, infants were seen for a developmental and diagnostic evaluation completed by examiners masked to participant group. Latent growth curve models were used to compare early trajectories of pull-to-sit performance in infants later diagnosed with ASD and typically developing infants and to predict developmental outcomes.

RESULTS

Pull-to-sit trajectories did not differ in infants with an elevated likelihood of ASD or infants with ASD compared with low-likelihood and typically developing infants, but infants with ASD were more likely to exhibit a head lag by age 4 months. In addition, pull-to-sit trajectories were predictive of social and speech skills 2 years later.

CONCLUSIONS

These findings highlight the link between very early pull-to-sit skills and later social and language outcomes. Atypical postural development and persistent presence of head lag may be important early indicators of social and language vulnerabilities, including ASD.

Brain structural parameters correlate with University Selection Test outcomes in Chilean high school graduates

How well students learn and perform in academic contexts is a focus of interest for the students, their families, and the entire educational system. Although evidence has shown that several neurobiological factors are involved in scholastic achievement (SA), specific brain measures associated with academic outcomes and whether such associations are independent of other factors remain unclear. This study attempts to identify the relationship between brain structural parameters, and the Chilean national University Selection Test (PSU) results in high school graduates within a multidimensional approach that considers socio-economic, intellectual, nutritional, and demographic variables. To this end, the brain morphology of a sample of 102 students who took the PSU test was estimated using Magnetic Resonance Imaging. Anthropometric parameters, intellectual ability (IA), and socioeconomic status (SES) were also measured. The results revealed that, independently of sex, IA, gray matter volume, right inferior frontal gyrus thickness, and SES were significantly associated with SA. These findings highlight the role of nutrition, health, and socioeconomic variables in academic success.

Montelukast reduces grey matter abnormalities and functional deficits in a mouse model of inflammation-induced encephalopathy of prematurity

Encephalopathy of prematurity (EoP) affects approximately 30% of infants born < 32 weeks gestation and is highly associated with inflammation in the foetus. Here we evaluated the efficacy of montelukast, a cysteinyl leukotriene receptor antagonist widely used to treat asthma in children, to ameliorate peripheral and central inflammation, and subsequent grey matter neuropathology and behaviour deficits in a mouse model of EoP. Male CD-1 mice were treated with intraperitoneal (i.p.) saline or interleukin-1beta (IL-1β, 40 μg/kg, 5 μL/g body weight) from postnatal day (P)1-5 ± concomitant montelukast (1-30 mg/kg). Saline or montelukast treatment was continued for a further 5 days post-injury. Assessment of systemic and central inflammation and short-term neuropathology was performed from 4 h following treatment through to P10. Behavioural testing, MRI and neuropathological assessments were made on a second cohort of animals from P36 to 54. Montelukast was found to attenuate both peripheral and central inflammation, reducing the expression of pro-inflammatory molecules (IL-1β, IL-6, TNF) in the brain. Inflammation induced a reduction in parvalbumin-positive interneuron density in the cortex, which was normalised with high-dose montelukast. The lowest effective dose, 3 mg/kg, was able to improve anxiety and spatial learning deficits in this model of inflammatory injury, and alterations in cortical mean diffusivity were not present in animals that received this dose of montelukast. Repurposed montelukast administered early after preterm birth may, therefore, improve grey matter development and outcome in EoP.

Early Ultrasonic Monitoring of Brain Growth and Later Neurodevelopmental Outcome in Very Preterm Infants

BACKGROUND AND PURPOSE

In infants born very preterm, monitoring of early brain growth could contribute to prediction of later neurodevelopment. Therefore, our aim was to investigate associations between 2 early cranial ultrasound markers (corpus callosum-fastigium and corpus callosum length) and neurodevelopmental outcome and the added value of both markers in the prediction of neurodevelopmental outcome based on neonatal risk factors and head circumference in very preterm infants.

MATERIALS AND METHODS

This prospective observational study included 225 infants born at <30 weeks' gestational age, of whom 153 were without any brain injury on cranial ultrasound. Corpus callosum-fastigium and corpus callosum length and head circumference were measured at birth, 29 weeks' gestational age, transfer from the neonatal intensive care unit to a level II hospital, and 2 months' corrected age. We analyzed associations of brain markers and their growth with cognitive, motor, language, and behavioral outcome at 2 years' corrected age.

RESULTS

In infants without brain injury, greater corpus callosum-fastigium length at 2 months was associated with better cognitive outcome. Corpus callosum length at 2 months was positively associated with cognitive, motor, and language outcome. Faster growth of the corpus callosum length between birth and 2 months was associated with better cognitive and motor function. Prediction of neurodevelopmental outcome based on neonatal risk factors with or without head circumference was significantly improved by adding corpus callosum length.

CONCLUSIONS

Both corpus callosum-fastigium and corpus callosum length on cranial ultrasound are associated with neurodevelopmental outcome of very preterm infants without brain injury at 2 years, but only corpus callosum length shows the added clinical utility in predicting neurodevelopmental outcome.

Associations between neonatal hypoglycaemia and brain volumes, cortical thickness and white matter microstructure in mid-childhood: An MRI study

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Neonatal hypoglycaemia is associated with damage to the brain in the acute phase.

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In mid-childhood, neonatal hypoglycaemia is associated with smaller brain regions.

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Deep grey matter regions such as the caudate and thalamus are implicated.

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Children with neonatal hypoglycemia had smaller occipital lobe cortical thickness.

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Grey matter may be especially vulnerable to long-term effects of neonatal hypoglycemia.

Neonatal hypoglycaemia is a common metabolic disorder that may cause brain damage, most visible in parieto-occipital regions on MRI in the acute phase. However, the long term effects of neonatal hypoglycaemia on the brain are not well understood. We investigated the association between neonatal hypoglycaemia and brain volumes, cortical thickness and white matter microstructure at 9–10 years.

Children born at risk of neonatal hypoglycaemia at ≥ 36 weeks’ gestation who took part in a prospective cohort study underwent brain MRI at 9–10 years. Neonatal hypoglycaemia was defined as at least one hypoglycaemic episode (at least one consecutive blood glucose concentration < 2.6 mmol/L) or interstitial episode (at least 10 min of interstitial glucose concentrations < 2.6 mmol/L). Brain volumes and cortical thickness were computed using Freesurfer. White matter microstructure was assessed using tract-based spatial statistics.

Children who had (n = 75) and had not (n = 26) experienced neonatal hypoglycaemia had similar combined parietal and occipital lobe volumes and no differences in white matter microstructure at nine years of age. However, those who had experienced neonatal hypoglycaemia had smaller caudate volumes (mean difference: −557 mm³, 95% confidence interval (CI), −933 to −182, p = 0.004) and smaller thalamus (−0.03%, 95%CI, −0.06 to 0.00; p = 0.05) and subcortical grey matter (−0.10%, 95%CI −0.20 to 0.00, p = 0.05) volumes as percentage of total brain volume, and thinner occipital lobe cortex (−0.05 mm, 95%CI −0.10 to 0.00, p = 0.05) than those who had not. The finding of smaller caudate volumes after neonatal hypoglycaemia was consistent across analyses of pre-specified severity groups, clinically detected hypoglycaemic episodes, and severity and frequency of hypoglycaemic events.

Neonatal hypoglycaemia is associated with smaller deep grey matter brain regions and thinner occipital lobe cortex but not altered white matter microstructure in mid-childhood.

Head circumference, total cerebral volume and neurodevelopment in preterm neonates

OBJECTIVES

To assess the association of head circumference (HC) <10th percentile at birth and discharge from the neonatal intensive care unit (NICU) with neurodevelopment in very preterm (24-32 weeks' gestational age) neonates, and to compare the association of HC and total cerebral volume (TCV) with neurodevelopmental outcomes.

DESIGN

In a prospective cohort, semiautomatically segmented TCV and manually segmented white matter injury (WMI) volumes were obtained. Multivariable regressions were used to study the association of HC and TCV with neurodevelopmental outcomes, accounting for birth gestational age, WMI and postnatal illness.

SETTING

Participants born in 2006-2013 at British Columbia Women's Hospital were recruited.

PATIENTS

168 neonates had HC measurements at birth and discharge and MRI at term-equivalent age (TEA). 143 children were assessed at 4.5 years.

MAIN OUTCOME MEASURES

Motor, cognitive and language outcomes at 4.5 years were assessed using the Movement Assessment Battery for Children Second Edition (M-ABC) and Wechsler Preschool and Primary Scale of Intelligence Third Edition Full Scale IQ (FSIQ) and Verbal IQ (VIQ).

RESULTS

Small birth HC was associated with lower M-ABC and FSIQ scores. In children with small birth HC, small discharge HC was associated with lower M-ABC, FSIQ and VIQ scores, while normal HC at discharge was no longer associated with adverse outcomes. HC strongly correlated with TCV at TEA. TCV did not correlate with outcomes.

CONCLUSIONS

Small birth HC is associated with poorer neurodevelopment, independent of postnatal illness and WMI. Normalisation of HC during NICU care appears to moderate this risk.

Early structural brain development in infants exposed to HIV and antiretroviral therapy in utero in a South African birth cohort

Introduction

There is a growing population of children who are HIV‐exposed and uninfected (HEU) with the successful expansion of antiretroviral therapy (ART) use in pregnancy. Children who are HEU are at risk of delayed neurodevelopment; however, there is limited research on early brain growth and maturation. We aimed to investigate the effects of in utero exposure to HIV/ART on brain structure of infants who are HEU compared to HIV‐unexposed (HU).

Methods

Magnetic resonance imaging using a T2‐weighted sequence was undertaken in a subgroup of infants aged 2–6 weeks enrolled in the Drakenstein Child Health Study birth cohort, South Africa, between 2012 and 2015. Mother–child pairs received antenatal and postnatal HIV testing and ART per local guidelines. We compared subcortical and total grey matter volumes between HEU and HU groups using multivariable linear regression adjusting for infant age, sex, intracranial volume and socio‐economic variables. We further assessed associations between brain volumes with maternal CD4 cell count and ART exposure.

Results

One hundred forty‐six infants (40 HEU; 106 HU) with high‐resolution images were included in this analysis (mean age 3 weeks; 50.7% male). All infants who were HEU were exposed to ART (88% maternal triple ART). Infants who were HEU had smaller caudate volumes bilaterally (5.4% reduction, p < 0.05) compared to HU infants. There were no group differences in other subcortical volumes (all p > 0.2). Total grey matter volume was also reduced in infants who were HEU (2.1% reduction, p < 0.05). Exploratory analyses showed that low maternal CD4 cell count (<350 cells/mm³) was associated with decreased infant grey matter volumes. There was no relationship between timing of ART exposure and grey matter volumes.

Conclusions

Lower caudate and total grey matter volumes were found in infants who were HEU compared to HU in the first weeks of life, and maternal immunosuppression was associated with reduced volumes. These findings suggest that antenatal HIV exposure may impact early structural brain development and improved antenatal HIV management may have the potential to optimize neurodevelopmental outcomes of children who are HEU.

Association between early-term birth and delayed neurodevelopment at the age of 2 years: results from a cohort study in China

A growing body of evidence indicates that early-term births (37-38 weeks of gestational age) have an increased risk of short-term and long-term complications. Here, we sought to explore the association between early-term births and the risk of delayed neurodevelopment at age 2 years. Pregnant women and their live singleton birth were recruited from a single tertiary hospital between October 2013 and February 2017. Mental and Psychomotor Development Indexes (MDI and PDI) were assessed using the Bayley Scales of Infant Development (BSID). Delayed neurodevelopment was defined as scores of PDI or MDI less than -1SD relative to the mean score of the study population. In total, 1678 full-term infants and 727 early-term infants were assessed when they were 2 years old. After adjustment for potential confounders, early-term birth was related to 43% increased odds of neurodevelopmental delay in the PDI domain as compared with full-term birth (OR: 1.43; 95% CI: 1.12, 1.82). The observed associations were more prominent among those infants born by cesarean (OR: 1.44; 95% CI: 1.03, 2.00) and among males (OR: 1.66; 95% CI: 1.20, 2.28). No statistical difference in the MDI domain was found between early-term and full-term births.Conclusions: Our findings suggest that early-term birth was associated with increased odds of delayed neurodevelopment in the PDI domain as measured by BSID assessments at age 2 years. Health professionals should be aware of the influence of early-term birth on the risk of delayed neurodevelopment. What is Known: • Evidence indicates that early-term births have an increased risk of short-term and long-term complications. • The association between early-term births and delayed neurodevelopment at their early childhood has not been widely studied. What is New: • Early-term birth was associated with increased odds of delayed neurodevelopment in PDI domain as measured by BSID assessments at age 2 years. • The observed associations were more prominent among infants born by cesarean section and among male infants.

Interaction between Preterm White Matter Injury and Childhood Thalamic Growth

OBJECTIVE

The purpose of this study was to determine how preterm white matter injury (WMI) and long-term thalamic growth interact to predict 8-year neurodevelopmental outcomes.

METHODS

A prospective cohort of 114 children born at 24 to 32 weeks' gestational age (GA) underwent structural and diffusion tensor magnetic resonance imaging early in life (median 32 weeks), at term-equivalent age and at 8 years. Manual segmentation of neonatal WMI was performed on T1-weighted images and thalamic volumes were obtained using the MAGeT brain segmentation pipeline. Cognitive, motor, and visual-motor outcomes were evaluated at 8 years of age. Multivariable regression was used to examine the relationship among neonatal WMI volume, school-age thalamic volume, and neurodevelopmental outcomes.

RESULTS

School-age thalamic volumes were predicted by neonatal thalamic growth rate, GA, sex, and neonatal WMI volume (p < 0.0001). After accounting for total cerebral volume, WMI volume remained associated with school-age thalamic volume (β = -0.31, p = 0.005). In thalamocortical tracts, fractional anisotropy (FA) at term-equivalent age interacted with early WMI volume to predict school-age thalamic volumes (all p < 0.02). School-age thalamic volumes and neonatal WMI interacted to predict full-scale IQ (p = 0.002) and adverse motor scores among those with significant WMI (p = 0.01). Visual-motor scores were predicted by thalamic volumes (p = 0.04).

INTERPRETATION

In very preterm-born children, neonatal thalamic growth and WMI volume predict school-age thalamic volumes. The emergence at term of an interaction between FA and WMI to impact school-age thalamic volume indicates dysmaturation as a mechanism of thalamic growth failure. Cognition is predicted by the interaction of WMI and thalamic growth, highlighting the need to consider multiple dimensions of brain injury in these children. ANN NEUROL 2021;90:584-594.

On the potential for mapping apparent neural soma density via a clinically viable diffusion MRI protocol

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B-tensor encoding enables estimation of spherical cellular structures in the brain.

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Spherical compartments may provide markers for apparent neural soma density.

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Model parameters can be estimated in a fast and robust way using deep learning.

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Practical acquisition times are achievable on widely available clinical scanners.

Diffusion MRI is a valuable tool for probing tissue microstructure in the brain noninvasively. Today, model-based techniques are widely available and used for white matter characterisation where their development is relatively mature. Conversely, tissue modelling in grey matter is more challenging, and no generally accepted models exist. With advances in measurement technology and modelling efforts, a clinically viable technique that reveals salient features of grey matter microstructure, such as the density of quasi-spherical cell bodies and quasi-cylindrical cell projections, is an exciting prospect. As a step towards capturing the microscopic architecture of grey matter in clinically feasible settings, this work uses a biophysical model that is designed to disentangle the diffusion signatures of spherical and cylindrical structures in the presence of orientation heterogeneity, and takes advantage of B-tensor encoding measurements, which provide additional sensitivity compared to standard single diffusion encoding sequences. For the fast and robust estimation of microstructural parameters, we leverage recent advances in machine learning and replace conventional fitting techniques with an artificial neural network that fits complex biophysical models within seconds. Our results demonstrate apparent markers of spherical and cylindrical geometries in healthy human subjects, and in particular an increased volume fraction of spherical compartments in grey matter compared to white matter. We evaluate the extent to which spherical and cylindrical geometries may be interpreted as correlates of neural soma and neural projections, respectively, and quantify parameter estimation errors in the presence of various departures from the modelling assumptions. While further work is necessary to translate the ideas presented in this work to the clinic, we suggest that biomarkers focussing on quasi-spherical cellular geometries may be valuable for the enhanced assessment of neurodevelopmental disorders and neurodegenerative diseases.

Individualized brain development and cognitive outcome in infants with congenital heart disease

Infants with congenital heart disease are at risk of neurodevelopmental impairments, the origins of which are currently unclear. This study aimed to characterize the relationship between neonatal brain development, cerebral oxygen delivery and neurodevelopmental outcome in infants with congenital heart disease. A cohort of infants with serious or critical congenital heart disease (N = 66; N = 62 born ≥37 weeks) underwent brain MRI before surgery on a 3T scanner situated on the neonatal unit. T2-weighted images were segmented into brain regions using a neonatal-specific algorithm. We generated normative curves of typical volumetric brain development using a data-driven technique applied to 219 healthy infants from the Developing Human Connectome Project (dHCP). Atypicality indices, representing the degree of positive or negative deviation of a regional volume from the normative mean for a given gestational age, sex and postnatal age, were calculated for each infant with congenital heart disease. Phase contrast angiography was acquired in 53 infants with congenital heart disease and cerebral oxygen delivery was calculated. Cognitive and motor abilities were assessed at 22 months (N = 46) using the Bayley scales of Infant and Toddler Development-Third Edition. We assessed the relationship between atypicality indices, cerebral oxygen delivery and cognitive and motor outcome. Additionally, we examined whether cerebral oxygen delivery was associated with neurodevelopmental outcome through the mediating effect of brain volume. Negative atypicality indices in deep grey matter were associated with both reduced neonatal cerebral oxygen delivery and poorer cognitive abilities at 22 months across the whole sample. In infants with congenital heart disease born ≥37 weeks, negative cortical grey matter and total tissue volume atypicality indices, in addition to deep grey matter structures, were associated with poorer cognition. There was a significant indirect relationship between cerebral oxygen delivery and cognition through the mediating effect of negative deep grey matter atypicality indices across the whole sample. In infants born ≥37 weeks, cortical grey matter and total tissue volume atypicality indices were also mediators of this relationship. In summary, lower cognitive abilities in toddlers with congenital heart disease were associated with smaller grey matter volumes before cardiac surgery. The aetiology of poor cognition may encompass poor cerebral oxygen delivery leading to impaired grey matter growth. Interventions to improve cerebral oxygen delivery may promote early brain growth and improve cognitive outcomes in infants with congenital heart disease.

The effects of the functional interplay between the Default Mode and Executive Control Resting State Networks on cognitive outcome in preterm born infants at 6 months of age

Preterm birth can affect cognitive functions, such as attention or more generally executive control mechanisms, with severity in impairments proportional to prematurity. The functional cross-talk between the Default Mode (DMN) and Executive Control (ECN) networks mirrors the integrity of cognitive processing and is directly related to brain development. In this study, a cohort of 20 preterm-born infants was investigated using rs-fMRI. First, we addressed biological maturity of the DMN per se and its interplay with the ECN in terms of patterns of increased functional connectivity. Second, we assessed the impact of the degree of prematurity on the DMN-ECN functional interplay development in relation to cognitive outcome at six months. Our results highlighted the emergence of DMN in preterm neonates, with connectivity strength and synchronization between the anterior DMN hub and frontal areas increasing as a function of biological maturity. Further, cognitive scores at 6 months were predicted by mPFC-ECN connectivity strength with degree of prematurity impacting on mPFC-ECN connectivity and triggering differential patterns of functional maturation of the ECN for very early/early and moderate/late preterm neonates. Our findings suggest that the prematurity window allows to observe precursors of functional plasticity that may underlie different developmental trajectories in preterm children.

Automated brain MRI metrics in the EPIRMEX cohort of preterm newborns: Correlation with the neurodevelopmental outcome at 2 years

PURPOSE

The purpose of this study was to identify in the EPIRMEX cohort the correlations between MRI brain metrics, including diffuse excessive high signal intensities (DEHSI) obtained with an automated quantitative method and neurodevelopmental outcomes at 2 years.

MATERIALS AND METHODS

A total of 390 very preterm infants (gestational age at birth≤32 weeks) who underwent brain MRI at term equivalent age at 1.5T (n=338) or 3T (n=52) were prospectively included. Using a validated algorithm, automated metrics of the main brain surfaces (cortical and deep gray matter, white matter, cerebrospinal fluid) and DEHSI with three thresholds were obtained. Linear adjust regressions were performed to assess the correlation between brain metrics with the ages and stages questionnaire (ASQ) score at 2 years.

RESULTS

Basal ganglia and thalami, cortex and white matter surfaces positively and significantly correlated with the global ASQ score. For all ASQ sub-domains, basal ganglia and thalami surfaces significantly correlated with the scores. DEHSI was present in 289 premature newborns (74%) without any correlation with the ASQ score. Metrics of DEHSI were greater at 3T than at 1.5T.

CONCLUSION

Brain MRI metrics obtained in our multicentric cohort correlate with the neurodevelopmental outcome at 2 years of age. The quantitative detection of DEHSI is not predictive of adverse outcomes. Our automated algorithm might easily provide useful predictive information in daily practice.

Correlation of lateral ventricular size and deep gray matter volume in MRI at term equivalent age with neurodevelopmental outcome at a corrected age of 24 months and with handedness in preterm infants

The aim of this study was to correlate ventricular size and volumes of deep gray matter (DGM) in MRI at term equivalent age (TEA) with outcome at a corrected age of 24 months in preterm infants and with handedness. Seventy-three infants born before 32 weeks of gestation or with birth weight < 1500 g  were included in this retrospective analysis and measurement of lateral ventricles, and DGM was performed on MRI scans. The left lateral ventricle was significantly larger than the right lateral ventricle (p = 0.001). There was no correlation between volumes of the right and left ventricles and the DGM volume (p = 0.207 and p = 0.597, respectively), nor with the head circumference at TEA (p = 0.177 and p = 0.976, respectively). The total volume of both lateral ventricles did not correlate with Mental Develomental Index (MDI, p = 0.336) or Psychomotor Developmental Index (PDI, p = 0.650) score (Bayley Scales of Infant Development, BSID II). However, a correlation of total DGM volume with birth weight (p = 0.0001; r = 0.437), head circumference at TEA (p < 0.0001; r = 0.640), MDI (p = 0.029; r = 0.310), and PDI (p = 0.002; r = 0.456) was observed. No significant difference between right- and left-handed infants was seen in relation to volumes of both lateral ventricles and of DGM.Conclusion: DGM volume at TEA was significantly associated with the outcome at a corrected age of 24 months. Handedness did not correlate with DGM or lateral ventricle size.What is Known:• White matter injury as well as altered development of deep gray matter is associated with neurodevelopmental disability in preterm infants.• No study analyzed the association between deep gray matter volume or volumes of lateral ventricle and handedness in former preterm infants so far.What is New:• Volume of deep gray matter, but not lateral ventricular size was significantly associated with outcome at a corrected age of 24 months in preterm infants.• There was no correlation of handedness with volumes of lateral ventricular size or with deep gray matter volumes.

Language Skills in Children Born Preterm (<30 Wks' Gestation) Throughout Childhood: Associations With Biological and Socioenvironmental Factors

OBJECTIVE

To examine the individual and collective contribution of biological and socioenvironmental factors associated with language function at 2, 5, 7, and 13 years in children born preterm (<30 weeks' gestation or <1250 g birth weight).

METHODS

Language function was assessed as part of a prospective longitudinal study of 224 children born preterm at 2, 5, 7, and 13 years using age-appropriate tools. Language Z-scores were generated based on a contemporaneous term-born control group. A selection of biological factors (sex, small for gestational age, bronchopulmonary dysplasia, infection, and qualitatively defined brain injury) and early socioenvironmental factors at age 2 years (primary income earner employment status and type, primary caregiver education level, English as a second language, parental mental health history, parent sensitivity and facilitation, and parent-child synchrony) was chosen a priori. Associations were assessed using univariable and multivariable linear regression models applied to outcomes at each time point.

RESULTS

Higher primary caregiver education level, greater parent-child synchrony, and parent sensitivity were independently associated with better language function across childhood. Socioenvironmental factors together explained an increasing percentage of the variance (9%-18%) in language function from 2 to 13 years of age. In comparison, there was little evidence for associations between biological factors and language function, even during early childhood years.

CONCLUSION

This study highlights the importance of socioenvironmental factors over biological factors for language development throughout childhood. Some of these socioenvironmental factors are potentially modifiable, and parent-based interventions addressing parenting practices and education may benefit preterm children's language development.

A machine learning investigation of volumetric and functional MRI abnormalities in adults born preterm

Imaging studies have characterized functional and structural brain abnormalities in adults after premature birth, but these investigations have mostly used univariate methods that do not account for hypothesized interdependencies between brain regions or quantify accuracy in identifying individuals. To overcome these limitations, we used multivariate machine learning to identify gray matter volume (GMV) and amplitude of low frequency fluctuations (ALFF) brain patterns that best classify young adults born very preterm/very low birth weight (VP/VLBW; n = 94) from those born full-term (FT; n = 92). We then compared the spatial maps of the structural and functional brain signatures and validated them by assessing associations with clinical birth history and basic cognitive variables. Premature birth could be predicted with a balanced accuracy of 80.7% using GMV and 77.4% using ALFF. GMV predictions were mediated by a pattern of subcortical and middle temporal reductions and volumetric increases of the lateral prefrontal, medial prefrontal, and superior temporal gyrus regions. ALFF predictions were characterized by a pattern including increases in the thalamus, pre- and post-central gyri, and parietal lobes, in addition to decreases in the superior temporal gyri bilaterally. Decision scores from each classification, assessing the degree to which an individual was classified as a VP/VLBW case, were predicted by the number of days in neonatal hospitalization and birth weight. ALFF decision scores also contributed to the prediction of general IQ, which highlighted their potential clinical significance. Combined, the results clarified previous research and suggested that primary subcortical and temporal damage may be accompanied by disrupted neurodevelopment of the cortex.

Exploration of gray matter correlates of cognitive training benefit in adolescents with chronic traumatic brain injury

Sustaining a traumatic brain injury (TBI) during adolescence has a profound effect on brain development and can result in persistent executive functioning deficits in daily life. Cognitive recovery from pediatric-TBI relies on the potential of neuroplasticity, which can be fostered by restorative training-programs. However the structural mechanisms underlying cognitive recovery in the immature brain are poorly understood. This study investigated gray matter plasticity following 2 months of cognitive training in young patients with TBI. Sixteen adolescents in the chronic stage of moderate-severe-TBI (9 male, mean age = 15y8m ± 1y7m) were enrolled in a cognitive computerized training program for 8 weeks (5 times/week, 40 min/session). Pre-and post-intervention, and 6 months after completion of the training, participants underwent a comprehensive neurocognitive test-battery and anatomical Magnetic Resonance Imaging scans. We selected 9 cortical-subcortical Regions-Of-Interest associated with Executive Functioning (EF-ROIs) and 3 control regions from the Desikan-Killiany atlas. Baseline analyses showed significant decreased gray matter density in the superior frontal gyri p = 0.033, superior parietal gyri p = 0.015 and thalamus p = 0.006 in adolescents with TBI compared to age and gender matched controls. Linear mixed model analyses of longitudinal volumetric data of the EF-ROI revealed no strong evidence of training-related changes in the group with TBI. However, compared to the change over time in the control regions between post-intervention and 6 months follow-up, the change in the EF-ROIs showed a significant difference. Exploratory analyses revealed a negative correlation between the change on the Digit Symbol Substitution test and the change in volume of the putamen (r = -0.596, p = 0.015). This preliminary study contributes to the insights of training-related plasticity mechanisms after pediatric-TBI.

Head circumference and child ADHD symptoms and cognitive functioning: results from a large population-based cohort study

The aim of this study is to understand the association between prenatal, newborn and postnatal head circumference (HC) and preschool neurodevelopment in a large population-based birth cohort. The INMA project followed 1795 children from 12 weeks of pregnancy to preschool years. HC measurements were carried out prospectively, and following a standardized protocol during pregnancy (12, 20 and 34 weeks), birth, and child ages of 1-1.5 and 4 years old; and z-scores were further estimated. Prenatal head growth was assessed using conditional z-scores between weeks 12-20 and 20-34. Several neuropsychological tests [MSCA (cognition), CPT (attention)] and behavioral rating scales [DSM-IV-ADHD, CAST (autism), CPSCS (social competence)] were carried out during the last follow-up (5 years old). Multivariable models adjusted for family and child characteristics were applied to analyze associations between HC and neurodevelopment. In fully adjusted models, prenatal HC and head growth showed little or no associations with the neurodevelopment outcomes. Independent associations were observed between HC z-scores at birth, 1-1.5 years and 4 years and MSCA global cognitive scores and DSM-IV inattention symptoms. Specifically, z-score at birth was positively associated with general cognitive scores [β 1.22, 95% confidence interval (CI) 0.59, 1.85], and we observed a protective association with ADHD-DSM-IV total symptoms, mean ratio (MR) 0.85 (0.75, 0.96). Prenatal HC and head growth measurements gave little information about child cognitive abilities and behavior at preschool years. However, HC at birth and early childhood was positively associated with a range of neuropsychological outcomes, including protective associations with ADHD symptoms.

Language Network Function in Young Children Born Very Preterm

Language deficits are reported in preterm born children across development. Recent neuroimaging studies have found functional alterations in large-scale brain networks underlying these language deficits, but the early childhood development of the language network has not been investigated. Here, we compared intrinsic language network connectivity in 4-year-old children born VPT and term-born controls, using defined language regions (Broca's area, Wernicke's areas, and their homologues in the right hemisphere). Resting-state functional magnetic resonance imaging (fMRI) was obtained, and the group differences in whole-brain connectivity were examined from each seed as well as correlations with language outcomes. We found significantly decreased functional connectivity in almost all language regions in children born VPT compared to their term controls. Notably, Broca's area homologue in the right hemisphere emerged as a functional hub of decreased connectivity in VPT group, specifically to bilateral inferior frontal and supramarginal gyri; connectivity strength between Broca's area homologue with the right supramarginal and the left inferior frontal gyri was associated with better language outcomes at 4 years of age. Wernicke's area and its homologue also showed decreased inter-hemispheric connections to bilateral supramarginal gyri in the VPT group. Decreased intra- and inter-hemispheric connectivity among primary language regions suggests immature and altered function in the language network in children born VPT.

Altered functional network connectivity relates to motor development in children born very preterm

Individuals born very preterm (<32 weeks gestation) are at increased risk for neuromotor impairments. The ability to characterize the structural and functional mechanisms underlying these impairments remains limited using existing neuroimaging techniques. Resting state-functional magnetic resonance imaging (rs-fMRI) holds promise for defining the functional network architecture of the developing brain in relation to typical and aberrant neurodevelopment. In 58 very preterm and 65 term-born children studied from birth to age 12 years, we examined relations between functional connectivity measures from low-motion rs-fMRI data and motor skills assessed using the Movement Assessment Battery for Children, 2nd edition. Across all subscales, motor performance was better in term than very preterm children. Examination of relations between functional connectivity and motor measures using enrichment analysis revealed between-group differences within cerebellar, frontoparietal, and default mode networks, and between basal ganglia-motor, thalamus-motor, basal ganglia-auditory, and dorsal attention-default mode networks. Specifically, very preterm children exhibited weaker associations between motor scores and thalamus-motor and basal ganglia-motor network connectivity. These findings highlight key functional brain systems underlying motor development. They also demonstrate persisting developmental effects of preterm birth on functional connectivity and motor performance in childhood, providing evidence for an alternative network architecture supporting motor function in preterm children.

Preterm Birth/Low Birth Weight and Markers Reflective of Wealth in Adulthood: A Meta-analysis

CONTEXT

Preterm birth and/or low birth weight (PT/LBW) increases the risk of cognitive deficits, which suggests an association between PT/LBW and lower wealth in adulthood. Nevertheless, studies have revealed inconsistent findings so far.

OBJECTIVE

To systematically investigate whether PT/LBW is associated with markers of adulthood wealth.

DATA SOURCES

We searched Medline, PubMed, PsycINFO, Web of Science, and Embase.

STUDY SELECTION

Prospective longitudinal and registry studies containing reports on selected wealth-related outcomes in PT/LBW-born adults compared with term-born controls.

DATA EXTRACTION

Two independent reviewers extracted data on educational qualifications, employment rates, social benefits, and independent living.

RESULTS

Of 1347 articles screened, 23 studies met the inclusion criteria. PT/LBW was associated with decreased likelihood of attainment of higher education qualifications (odds ratio [OR] = 0.74; 95% confidence interval [CI] = 0.69-0.80), lower employment rate (OR = 0.83; 95% CI = 0.74-0.92), and increased likelihood of receiving social benefits (OR = 1.25; 95% CI = 1.09-1.42). A dose-response relationship according to gestational age was only found for education qualifications. PT/LBW-born adults did not differ significantly from those born at term in independent living.

LIMITATIONS

There was high heterogeneity between studies. There were unequal numbers of studies from different regions in the world.

CONCLUSIONS

PT/LBW is associated with lower educational qualifications, decreased rate of employment, and an increased rate of receipt of social benefits in adulthood. Low educational qualifications were most prevalent in those born very preterm and consistent across geographic regions. However, the findings are less clear for independent living.

Longitudinal Study of White Matter Development and Outcomes in Children Born Very Preterm

Identifying trajectories of early white matter development is important for understanding atypical brain development and impaired functional outcomes in children born very preterm (<32 weeks gestational age [GA]). In this study, 161 diffusion images were acquired in children born very preterm (median GA: 29 weeks) shortly following birth (75), term-equivalent (39), 2 years (18), and 4 years of age (29). Diffusion tensors were computed to obtain measures of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD), which were aligned and averaged. A paediatric atlas was applied to obtain diffusion metrics within 12 white matter tracts. Developmental trajectories across time points demonstrated age-related changes which plateaued between term-equivalent and 2 years of age in the majority of posterior tracts and between 2 and 4 years of age in anterior tracts. Between preterm and term-equivalent scans, FA rates of change were slower in anterior than posterior tracts. Partial least squares analyses revealed associations between slower MD and RD rates of change within the external and internal capsule with lower intelligence quotients and language scores at 4 years of age. These results uniquely demonstrate early white matter development and its linkage to cognitive functions.

Brain growth in the NICU: critical periods of tissue-specific expansion

ObjectiveTo examine, using serial magnetic resonance imaging (MRI), total and tissue-specific brain growth in very-preterm (VPT) infants during the period that coincides with the early and late stages of the third trimester.MethodsStructural MRI scans were collected from two prospective cohorts of VPT infants (≤30 weeks of gestation). A total of 51 MRI scans from 18 VPT subjects were available for volumetric analysis. Brain tissue was classified into cerebrospinal fluid, cortical gray matter, myelinated and unmyelinated white matter, deep nuclear gray matter, and cerebellum. Nine infants had sufficient serial scans to allow comparison of tissue growth during the periods corresponding to the early and late stages of the third trimester.ResultsTissue-specific differences in ex utero brain growth trajectories were observed in the period corresponding to the third trimester. Most notably, there was a marked increase in cortical gray matter expansion from 34 to 40 weeks of postmenstrual age, emphasizing this critical period of brain development.ConclusionUtilizing serial MRI to document early brain development in VPT infants, this study documents regional differences in brain growth trajectories ex utero during the period corresponding to the first and second half of the third trimester, providing novel insight into the maturational vulnerability of the rapidly expanding cortical gray matter in the NICU.

Visual-motor integration and fine motor skills at 6½ years of age and associations with neonatal brain volumes in children born extremely preterm in Sweden: a population-based cohort study

OBJECTIVES

This exploratory study aimed to investigate associations between neonatal brain volumes and visual-motor integration (VMI) and fine motor skills in children born extremely preterm (EPT) when they reached 6½ years of age.

SETTING

Prospective population-based cohort study in Stockholm, Sweden, during 3 years.

PARTICIPANTS

All children born before gestational age, 27 weeks, during 2004-2007 in Stockholm, without major morbidities and impairments, and who underwent MRI at term-equivalent age.

MAIN OUTCOME MEASURES

Brain volumes were calculated using morphometric analyses in regions known to be involved in VMI and fine motor functions. VMI was assessed with The Beery-Buktenica Developmental Test of Visual-Motor Integration-sixth edition and fine motor skills were assessed with the manual dexterity subtest from the Movement Assessment Battery for Children-second edition, at 6½ years. Associations between the brain volumes and VMI and fine motor skills were evaluated using partial correlation, adjusted for total cerebral parenchyma and sex.

RESULTS

Out of 107 children born at gestational age <27 weeks, 83 were assessed at 6½ years and 66/83 were without major brain lesions or cerebral palsy and included in the analyses. A representative subsample underwent morphometric analyses: automatic segmentation (n=34) and atlas-based segmentation (n=26). The precentral gyrus was associated with both VMI (r=0.54, P=0.007) and fine motor skills (r=0.54, P=0.01). Associations were also seen between fine motor skills and the volume of the cerebellum (r=0.42, P=0.02), brainstem (r=0.47, P=0.008) and grey matter (r=-0.38, P=0.04).

CONCLUSIONS

Neonatal brain volumes in areas known to be involved in VMI and fine motor skills were associated with scores for these two functions when children born EPT without major brain lesions or cerebral palsy were evaluated at 6½ years of age. Establishing clear associations between early brain volume alterations and later VMI and/or fine motor skills could make early interventions possible.

Neonatal basal ganglia and thalamic volumes: very preterm birth and 7-year neurodevelopmental outcomes

BackgroundThis study aims to (i) compare volumes of individual basal ganglia nuclei (caudate nucleus, pallidum, and putamen) and the thalamus between very preterm (VP) and term-born infants at term-equivalent age; (ii) explore neonatal basal ganglia and thalamic volume relationships with 7-year neurodevelopmental outcomes, and whether these relationships differed between VP and term-born children.Methods210 VP (<30 weeks' gestational age) and 39 term-born (≥37 weeks' gestational age) infants underwent brain magnetic resonance imaging at term-equivalent age, and deep gray matter volumes of interest were automatically generated. 186 VP and 37 term-born children were assessed for a range of neurodevelopmental measures at age 7 years.ResultsAll deep gray matter structures examined were smaller in VP infants compared with controls at term-equivalent age; ranging from (percentage mean difference (95% confidence intervals) -6.2% (-10.2%, -2.2%) for the putamen, to -9.5% (-13.9%, -5.1%) for the caudate nucleus. Neonatal basal ganglia and thalamic volumes were positively related to motor, intelligence quotient, and academic outcomes at age 7 years, with mostly similar relationships in the VP and control groups.ConclusionVP birth results in smaller basal ganglia and thalamic volumes at term-equivalent age, and these smaller volumes are related to a range of 7-year neurodevelopmental deficits in VP children.

Regional volumetric assessment of the brain in moderately preterm infants (30-35 gestational weeks) scanned at term-equivalent age on magnetic resonance imaging

BACKGROUND

Early volume analyses of the infantile brain may help predict neurodevelopmental outcome. However, brain volumes are not well understood in moderately preterm infants at term-equivalent age (TEA).

AIM

This study retrospectively investigated the relationship between regional brain volumes and infant gestational age (GA) at birth in moderately preterm infants (30-35weeks' GA) on magnetic resonance imaging (MRI) at TEA.

METHODS

Forty infants scanned at TEA were enrolled. Regional brain volumes were estimated by manual segmentation on MRI, and their relationship with GA at birth was assessed.

RESULTS

The regional volumes of the cerebral hemispheres and deep gray matter were larger (Spearman ρ=0.40, P=0.01, and Spearman ρ=0.48, P<0.01, respectively), and volumes of the lateral ventricles were smaller (Spearman ρ=-0.32, P=0.04) in infants born at a later GA. The volumes of the cerebral hemispheres of the infants born at 30weeks' GA were significantly smaller than those born at 33 and 35weeks' GA (P<0.05). No associations were found between the volume of the cerebellum and brainstem, and GA at birth (Spearman ρ=0.24, P=0.13, and Spearman ρ=0.24, P=0.14, respectively).

CONCLUSIONS

The volumes of the cerebral hemispheres at TEA may be smaller in infants born at 30weeks' GA, whereas those of the cerebellum and brainstem may not be correlated with GA among moderately preterm infants.

New Ultrasound Measurements to Bridge the Gap between Prenatal and Neonatal Brain Growth Assessment

BACKGROUND AND PURPOSE

Most ultrasound markers for monitoring brain growth can only be used in either the prenatal or the postnatal period. We investigated whether corpus callosum length and corpus callosum-fastigium length could be used as markers for both prenatal and postnatal brain growth.

MATERIALS AND METHODS

A 3D ultrasound study embedded in the prospective Rotterdam Periconception Cohort was performed at 22, 26 and 32 weeks' gestational age in fetuses with fetal growth restriction, congenital heart defects, and controls. Postnatally, cranial ultrasound was performed at 42 weeks' postmenstrual age. First, reliability was evaluated. Second, associations between prenatal and postnatal corpus callosum and corpus callosum-fastigium length were investigated. Third, we created reference curves and compared corpus callosum and corpus callosum-fastigium length growth trajectories of controls with growth trajectories of fetuses with fetal growth retardation and congenital heart defects.

RESULTS

We included 199 fetuses; 22 with fetal growth retardation, 20 with congenital heart defects, and 157 controls. Reliability of both measurements was excellent (intraclass correlation coefficient ≥ 0.97). Corpus callosum growth trajectories were significantly decreased in fetuses with fetal growth restriction and congenital heart defects (β = -2.295; 95% CI, -3.320-1.270; P < .01; β = -1.267; 95% CI, -0.972-0.562; P < .01, respectively) compared with growth trajectories of controls. Corpus callosum-fastigium growth trajectories were decreased in fetuses with fetal growth restriction (β = -1.295; 95% CI, -2.595-0.003; P = .05).

CONCLUSIONS

Corpus callosum and corpus callosum-fastigium length may serve as reliable markers for monitoring brain growth from the prenatal into the postnatal period. The clinical applicability of these markers was established by the significantly different corpus callosum and corpus callosum-fastigium growth trajectories in fetuses at risk for abnormal brain growth compared with those of controls.

A longitudinal study of associations between psychiatric symptoms and disorders and cerebral gray matter volumes in adolescents born very preterm

Background

Being born preterm with very low birthweight (VLBW ≤ 1500 g) poses a risk for cortical and subcortical gray matter (GM) abnormalities, as well as for having more psychiatric problems during childhood and adolescence than term-born individuals. The aim of this study was to investigate the relationship between cortical and subcortical GM volumes and the course of psychiatric disorders during adolescence in VLBW individuals.

Methods

We followed VLBW individuals and term-born controls (birth weight ≥10th percentile) from 15 (VLBW;controls n = 40;56) to 19 (n = 44;60) years of age. Of these, 30;37 individuals were examined longitudinally. Cortical and subcortical GM volumes were extracted from MRPRAGE images obtained with the same 1.5 T MRI scanner at both time points and analyzed at each time point with the longitudinal stream of the FreeSurfer software package 5.3.0. All participants underwent clinical interviews and were assessed for psychiatric symptoms and diagnosis (Schedule for Affective Disorders and Schizophrenia for School-age Children, Children’s Global Assessment Scale, Attention-Deficit/Hyperactivity Disorder Rating Scale-IV). VLBW adolescents were divided into two groups according to diagnostic status from 15 to 19 years of age: persisting/developing psychiatric diagnosis or healthy/becoming healthy.

Results

Reduction in subcortical GM volume at 15 and 19 years, not including the thalamus, was limited to VLBW adolescents with persisting/developing diagnosis during adolescence, whereas VLBW adolescents in the healthy/becoming healthy group had similar subcortical GM volumes to controls. Moreover, across the entire VLBW group, poorer psychosocial functioning was predicted by smaller subcortical GM volumes at both time points and with reduced GM volume in the thalamus and the parietal and occipital cortex at 15 years. Inattention problems were predicted by smaller GM volumes in the parietal and occipital cortex.

Conclusions

GM volume reductions in the parietal and occipital cortex as well as smaller thalamic and subcortical GM volumes were associated with the higher rates of psychiatric symptoms found across the entire VLBW group. Significantly smaller subcortical GM volumes in VLBW individuals compared with term-born peers might pose a risk for developing and maintaining psychiatric diagnoses during adolescence. Future research should explore the possible role of reduced cortical and subcortical GM volumes in the pathogenesis of psychiatric illness in VLBW adolescents.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-017-0793-0) contains supplementary material, which is available to authorized users.

Advanced neuroimaging and its role in predicting neurodevelopmental outcomes in very preterm infants

Up to 35% of very preterm infants survive with neurodevelopmental impairments (NDI) such as cognitive deficits, cerebral palsy, and attention deficit disorder. Advanced MRI quantitative tools such as brain morphometry, diffusion MRI, magnetic resonance spectroscopy, and functional MRI at term-equivalent age are ideally suited to improve current efforts to predict later development of disabilities. This would facilitate application of targeted early intervention therapies during the first few years of life when neuroplasticity is optimal. A systematic search and review identified 47 published studies of advanced MRI to predict NDI. Diffusion MRI and morphometry studies were the most commonly studied modalities. Despite several limitations, studies clearly showed that brain structural and metabolite biomarkers are promising independent predictors of NDI. Large representative multicenter studies are needed to validate these studies.

A New Ultrasound Marker for Bedside Monitoring of Preterm Brain Growth

BACKGROUND AND PURPOSE

Preterm neonates are at risk for neurodevelopmental impairment, but reliable, bedside-available markers to monitor preterm brain growth during hospital stay are still lacking. The aim of this study was to assess the feasibility of corpus callosum-fastigium length as a new cranial sonography marker for monitoring of preterm brain growth.

MATERIALS AND METHODS

In this longitudinal prospective cohort study, cranial ultrasound was planned on the day of birth, days 1, 2, 3, and 7 of life; and then weekly until discharge in preterm infants born before 29 weeks of gestational age. Reproducibility and associations between clinical variables and corpus callosum-fastigium growth trajectories were studied.

RESULTS

A series of 1-8 cranial ultrasounds was performed in 140 infants (median gestational age at birth, 27(+2) weeks (interquartile range, 26(+1) to 28(+1); 57.9% male infants). Corpus callosum-fastigium measurements showed good-to-excellent agreement for inter- and intraobserver reproducibility (intraclass correlation coefficient >0.89). Growth charts for preterm infants between 24 and 32 weeks of gestation were developed. Male sex and birth weight SD score were positively associated with corpus callosum-fastigium growth rate.

CONCLUSIONS

Corpus callosum-fastigium length measurement is a new reproducible marker applicable for bedside monitoring of preterm brain growth during neonatal intensive care stay.

Neurocognitive and Academic Outcomes at Age 10 Years of Extremely Preterm Newborns

BACKGROUND AND OBJECTIVE

Despite reductions in mortality and morbidity among children born extremely preterm, they remain at high risk of neurocognitive deficits, with up to 40% having significant cognitive deficits at school age. We assessed the rate of neurocognitive impairment in a contemporary US cohort of 873 children aged 10 years who were born <28 weeks' gestation.

METHODS

The families of 889 of 966 (92%) children enrolled from 2002 to 2004 at 14 sites in 5 states returned at age 10 years for a comprehensive assessment of IQ, language, attention, executive function, processing speed, visual perception, visual-motor function, and academic achievement.

RESULTS

A total of 873 children were assessed with well-validated tests of cognitive and academic function. Distributions of test scores were consistently and markedly shifted below normative expectation, with one-third to two-thirds of children performing >1 SD below age expectation. The most extreme downward shifts were on measures of executive control and processing speed. Multivariate analyses, adjusted for socioeconomic status, growth restriction, and other potential confounders, revealed that the risk of poor outcome was highest at the lowest gestational age across all 18 measures.

CONCLUSIONS

More than half of our extremely preterm cohort exhibited moderate or severe neurocognitive deficits at age 10 years, with the most extensive impairments found among those born at the lowest gestational age. Children born extremely preterm continue to be at significant risk of persistent impairments in neurocognitive function and academic achievement, underscoring the need for monitoring and remediating such outcomes beginning in early childhood.

Imaging the "At-Risk" Brain: Future Directions

OBJECTIVES

Clinical neuroscience is increasingly turning to imaging the human brain for answers to a range of questions and challenges. To date, the majority of studies have focused on the neural basis of current psychiatric symptoms, which can facilitate the identification of neurobiological markers for diagnosis. However, the increasing availability and feasibility of using imaging modalities, such as diffusion imaging and resting-state fMRI, enable longitudinal mapping of brain development. This shift in the field is opening the possibility of identifying predictive markers of risk or prognosis, and also represents a critical missing element for efforts to promote personalized or individualized medicine in psychiatry (i.e., stratified psychiatry).

METHODS

The present work provides a selective review of potentially high-yield populations for longitudinal examination with MRI, based upon our understanding of risk from epidemiologic studies and initial MRI findings.

RESULTS

Our discussion is organized into three topic areas: (1) practical considerations for establishing temporal precedence in psychiatric research; (2) readiness of the field for conducting longitudinal MRI, particularly for neurodevelopmental questions; and (3) illustrations of high-yield populations and time windows for examination that can be used to rapidly generate meaningful and useful data. Particular emphasis is placed on the implementation of time-appropriate, developmentally informed longitudinal designs, capable of facilitating the identification of biomarkers predictive of risk and prognosis.

CONCLUSIONS

Strategic longitudinal examination of the brain at-risk has the potential to bring the concepts of early intervention and prevention to psychiatry.

Diffusion tensor imaging-based assessment of white matter tracts and visual-motor outcomes in very preterm neonates

INTRODUCTION

The purpose of this study was to assess the impact of brain injury on white matter development and long-term outcomes in very preterm (VPT) neonates.

METHODS

Eighty-five VPT neonates (born <32/40 weeks gestational age (GA)) scanned within 2 weeks of birth were divided into three groups based on the presence of perinatal cerebral injury: (i) no injury, (ii) mild/moderate injury and (iii) severe injury. Diffusion tensor imaging (DTI) was acquired for each neonate and fractional anisotropy (FA), and diffusivity measures were calculated in the posterior limb of the internal capsule (PLIC) and optic radiation (OR). At 2 and 4 years of age, 41 and 44 children were assessed for motor and visual-motor abilities. Analyses determined the relation between GA and DTI measures, injury groups and DTI measures as well as developmental assessments.

RESULTS

GA was related to all DTI measures within the PLIC bilaterally, FA in the OR bilaterally and AD in the left OR. The severely injured group had significantly different DTI measures in the left PLIC compared to the other two groups, independent of lateralization of lesions. Group differences in the left OR were also found, due to higher incidence of the white matter injury in the left hemisphere. No differences were found between groups and outcome measures at 2 and 4 years, with the exception of destructive periventricular venous haemorrhagic infarction (PVHI).

CONCLUSIONS

DTI measures of the PLIC and OR were affected by injury in VPT neonates. These findings seen shortly after birth did not always translate into long-term motor and visual-motor impairments suggesting compensatory mechanisms.

Machine-learning to characterise neonatal functional connectivity in the preterm brain

Brain development is adversely affected by preterm birth. Magnetic resonance image analysis has revealed a complex fusion of structural alterations across all tissue compartments that are apparent by term-equivalent age, persistent into adolescence and adulthood, and associated with wide-ranging neurodevelopment disorders. Although functional MRI has revealed the relatively advanced organisational state of the neonatal brain, the full extent and nature of functional disruptions following preterm birth remain unclear.

In this study, we apply machine-learning methods to compare whole-brain functional connectivity in preterm infants at term-equivalent age and healthy term-born neonates in order to test the hypothesis that preterm birth results in specific alterations to functional connectivity by term-equivalent age.

Functional connectivity networks were estimated in 105 preterm infants and 26 term controls using group-independent component analysis and a graphical lasso model. A random forest–based feature selection method was used to identify discriminative edges within each network and a nonlinear support vector machine was used to classify subjects based on functional connectivity alone.

We achieved 80% cross-validated classification accuracy informed by a small set of discriminative edges. These edges connected a number of functional nodes in subcortical and cortical grey matter, and most were stronger in term neonates compared to those born preterm. Half of the discriminative edges connected one or more nodes within the basal ganglia.

These results demonstrate that functional connectivity in the preterm brain is significantly altered by term-equivalent age, confirming previous reports of altered connectivity between subcortical structures and higher-level association cortex following preterm birth.

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Robust classification of preterm and term-born neonates using functional connectivity patterns.

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Discriminative pattern of alterations in basal ganglia and frontal connections.

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Reflects system-wide disruption of subcortical–cortical connections following preterm birth.