Altered gray matter volume and school age anxiety in children born late preterm

Amygdala structure and function and its associations with social-emotional outcomes in a low-risk preterm sample

Amygdala atypical volume development and functional connectivity (FC) at small gestational ages (GA) have been found across childhood. This adult-oriented study assesses whether altered amygdala structure and function is present following low-risk preterm birth. T1-weighted and resting-state functional MRI images of 33 low-risk preterm (30-36 weeks' GA) and 29 full-term (37-42 weeks' GA) young adults of both sexes, aged between 20 and 32 years old, were analyzed using FreeSurfer (v6.0.0) and Coon Toolbox (v21.a). The social-emotional assessment included Happé's Strange Stories Test, the Moral Judgment Test, Delay-Discounting Test, Adult Self Report, and Emotion Regulation Questionnaire. No differences were found in social-emotional outcomes or amygdala volumes between the groups. Low-risk preterm young adults showed increased FC between the left amygdala, right amygdala and medial frontal cortex (MedFC) (F = 9.89, p-FWE = 0.009) at cluster level compared to their full-term peers. However, significant results at connection level were not observed between left and right amygdala. Lastly, increased FC at cluster level between the right amygdala and MedFC, and left amygdala and MedFC, was related to better social-emotional outcomes only in low-risk preterm young adults (F = 6.60, p-FWE = 0.036) at cluster level. At connection level, in contrast, only right amygdala-MedFC increased FC was significantly associated with better social-emotional outcomes. This study reveals that low-risk prematurity does not have an effect on social-emotional outcomes or structural amygdala volumes during young adulthood. However, individuals who were considered to be at a lower risk of exhibiting neurodevelopmental alterations following preterm birth demonstrated increased FC between the left and right amygdala and MedFC.

Growth of prefrontal and limbic brain regions and anxiety disorders in children born very preterm

BACKGROUND

Children born very preterm (VP) display altered growth in corticolimbic structures compared with full-term peers. Given the association between the cortiocolimbic system and anxiety, this study aimed to compare developmental trajectories of corticolimbic regions in VP children with and without anxiety diagnosis at 13 years.

METHODS

MRI data from 124 VP children were used to calculate whole brain and corticolimbic region volumes at term-equivalent age (TEA), 7 and 13 years. The presence of an anxiety disorder was assessed at 13 years using a structured clinical interview.

RESULTS

VP children who met criteria for an anxiety disorder at 13 years (n = 16) displayed altered trajectories for intracranial volume (ICV, p < 0.0001), total brain volume (TBV, p = 0.029), the right amygdala (p = 0.0009) and left hippocampus (p = 0.029) compared with VP children without anxiety (n = 108), with trends in the right hippocampus (p = 0.062) and left medial orbitofrontal cortex (p = 0.079). Altered trajectories predominantly reflected slower growth in early childhood (0-7 years) for ICV (β = -0.461, p = 0.020), TBV (β = -0.503, p = 0.021), left (β = -0.518, p = 0.020) and right hippocampi (β = -0.469, p = 0.020) and left medial orbitofrontal cortex (β = -0.761, p = 0.020) and did not persist after adjusting for TBV and social risk.

CONCLUSIONS

Region- and time-specific alterations in the development of the corticolimbic system in children born VP may help to explain an increase in anxiety disorders observed in this population.

Large-scale brain network dynamics in very preterm children and relationship with socio-emotional outcomes: an exploratory study

BACKGROUND

Children born very preterm (VPT; <32 weeks' gestation) are at high risk of neurodevelopmental and behavioural difficulties associated with atypical brain maturation, including socio-emotional difficulties. The analysis of large-scale brain network dynamics during rest allows us to investigate brain functional connectivity and its association with behavioural outcomes.

METHODS

Dynamic functional connectivity was extracted by using the innovation-driven co-activation patterns framework in VPT and full-term children aged 6-9 to explore changes in spatial organisation, laterality and temporal dynamics of spontaneous large-scale brain activity (VPT, n = 28; full-term, n = 12). Multivariate analysis was used to explore potential biomarkers for socio-emotional difficulties in VPT children.

RESULTS

The spatial organisation of the 13 retrieved functional networks was comparable across groups. Dynamic features and lateralisation of network brain activity were also comparable for all brain networks. Multivariate analysis unveiled group differences in associations between dynamical functional connectivity parameters with socio-emotional abilities.

CONCLUSION

In this exploratory study, the group differences observed might reflect reduced degrees of maturation of functional architecture in the VPT group in regard to socio-emotional abilities. Dynamic features of functional connectivity could represent relevant neuroimaging markers and inform on potential mechanisms through which preterm birth leads to neurodevelopmental and behavioural disorders.

IMPACT

Spatial organisation of the retrieved resting-state networks was comparable between school-aged very preterm and full-term children. Dynamic features and lateralisation of network brain activity were also comparable across groups. Multivariate pattern analysis revealed different patterns of association between dynamical functional connectivity parameters and socio-emotional abilities in the very preterm and full-term groups. Findings suggest a reduced degree of maturation of the functional architecture in the very preterm group in association with socio-emotional abilities.

Lower gestational age is associated with lower cortical volume and cognitive and educational performance in adolescence

BACKGROUND

Gestational age (GA) is associated with later cognition and behavior. However, it is unclear how specific cognitive domains and brain structural development varies with the stepwise change of gestational duration.

METHODS

This large-scale longitudinal cohort study analyzed 11,878 early adolescents' brain volume maps at 9-10 years (baseline) and 5685 at 11-12 years (a 2-year follow-up) from the Adolescent Brain Cognitive Development (ABCD) study. According to gestational age, adolescents were divided into five categorical groups: ≤ 33 weeks, 34-35 weeks, 36 weeks, 37-39 weeks, and ≥ 40 weeks. The NIH Toolbox was used to estimate neurocognitive performance, including crystallized and fluid intelligence, which was measured for 11,878 adolescents at baseline with crystallized intelligence and relevant subscales obtained at 2-year follow-up (with participant numbers ranging from 6185 to 6310 depending on the cognitive domain). An additional large population-based cohort of 618,070 middle adolescents at ninth-grade (15-16 years) from the Danish national register was utilized to validate the association between gestational age and academic achievements. A linear mixed model was used to examine the group differences between gestational age and neurocognitive performance, school achievements, and grey matter volume. A mediation analysis was performed to examine whether brain structural volumes mediated the association between GA and neurocognition, followed with a longitudinal analysis to track the changes.

RESULTS

Significant group differences were found in all neurocognitive scores, school achievements, and twenty-five cortical regional volumes (P < 0.05, Bonferroni corrected). Specifically, lower gestational ages were associated with graded lower cognition and school achievements and with smaller brain volumes of the fronto-parieto-temporal, fusiform, cingulate, insula, postcentral, hippocampal, thalamic, and pallidal regions. These lower brain volumes mediated the association between gestational age and cognitive function (P = 1 × 10^-8, β = 0.017, 95% CI: 0.007-0.028). Longitudinal analysis showed that compared to full term adolescents, preterm adolescents still had smaller brain volumes and crystallized intelligence scores at 11-12 years.

CONCLUSIONS

These results emphasize the relationships between gestational age at birth and adolescents' lower brain volume, and lower cognitive and educational performance, measured many years later when 9-10 and 11-12 years old. The study indicates the importance of early screening and close follow-up for neurocognitive and behavioral development for children and adolescents born with gestational ages that are even a little lower than full term.

Anxiety, Depression, and Behavioral and/or Conduct Disorder in Adolescence Among Former Preterm and Term Infants of Different Race and Ethnicities

OBJECTIVE

To compare parental reports of recent diagnoses of anxiety, depression, and/or behavioral/conduct disorder among former preterm (PT) and term adolescents by race/ethnicity and evaluate receipt of mental healthcare within the past year among those adolescents with any of these conditions.

STUDY DESIGN

A total of 20,871 Non-Hispanic white (NHW), Non-Hispanic black (NHB), and Hispanic adolescents were evaluated using data from the 2017/2018 National Survey of Children's Health. PT birth and race/ethnicity disparity in the diagnosis of these emotional/behavioral problems and receipt of mental healthcare among adolescents with any of these diagnoses were analyzed using logistic regression.

RESULTS

The unadjusted prevalence (95% CI) of these diagnoses was significantly higher among former PT (0.19 [0.17-0.22]) compared to term (0.15 [0.14-0.16]) adolescents. Despite having higher rates of adverse socioeconomic measures, former PT and term NHBs and Hispanics had lower unadjusted prevalence of these diagnoses in comparison to NHWs. After adjusting for differences in demographic, clinical, and socioeconomic characteristics, NHBs (0.47 [0.36-0.64]) and Hispanics (0.40 [0.30-0.54]) remain at lower odds of the composite measure of the emotional and/or behavioral problems compared to NHWs, while PT birth did not have a significant impact on this outcome measure. Only 53% of adolescents with these diagnoses received recent mental healthcare. No significant differences in the adjusted odds of receipt of mental healthcare were noted across the groups based on PT birth or race/ethnicity.

CONCLUSIONS

In contrast to PT birth, race/ethnicity had a significant impact on the adjusted odds of emotional/behavioral disorders during adolescence. Among adolescents with these diagnoses, PT birth and race/ethnicity did not significantly influence the adjusted odds of receipt of mental healthcare.

Cortical Morphometry and Its Relationship with Cognitive Functions in Children after non-CNS Cancer

Background: Childhood cancer survivors (Ccs) are at risk for cognitive late-effects, which might result from cortical alterations, even if cancer does not affect the brain. The study aimed to examine gray and white matter volume and its relationship to cognition. Methods: Forty-three Ccs of non-central nervous system cancers and 43 healthy controls, aged 7-16 years, were examined. Cognitive functions and fine motor coordination were assessed and T1-weighted images were collected for voxel-based morphometry. Results: Executive functions (p = .024, d = .31) were poorer in Ccs than controls, however still within the normal range. The volume of the amygdala (p = .011, ŋ² = .117) and the striatum (p = .03, ŋ² = .102) was reduced in Ccs. No significant structure-function correlations were found, neither in patients nor controls. Conclusion: Non-CNS childhood cancer and its treatment impacts on brain structures relevant to emotion processing.

Decreased amygdala volume in adults after premature birth

Premature-born infants have impaired amygdala structure, presumably due to increased stress levels of premature birth mediated by the amygdala. However, accounting for lifelong plasticity of amygdala, it is unclear whether such structural changes persist into adulthood. To address this problem, we stated the following questions: first, are whole amygdala volumes reduced in premature-born adults? And second, as adult anxiety traits are often increased after prematurity and linked with amygdala structure, are alterations in amygdala associated with adults' anxiety traits after premature birth? We addressed these questions by automated amygdala segmentation of MRI volumes in 101 very premature-born adults (< 32 weeks of gestation and/or birth weight below 1500 g) and 108 full-term controls at 26 years of age of a prospectively and longitudinally collected cohort. We found significantly lower whole amygdala volumes in premature-born adults. While premature-born adults had significantly higher T score for avoidant personality reflecting increased social anxiety trait, this trait was not correlated with amygdala volume alterations. Results demonstrate reduced amygdala volumes in premature born adults. Data suggest lasting effects of prematurity on amygdala structure.

Anxiety and Depressive Disorders in Children Born Preterm: A Meta-Analysis

OBJECTIVE

Preterm birth is associated with a high prevalence of psychiatric disorders including internalizing problems. However, there is a lack of consensus on the risk for depression and on specific diagnostic profiles. This meta-analysis investigates the independent pooled odds of Diagnostic and Statistical Manual of Mental Disorders Fourth Edition anxiety and depressive disorders in children between 3 and 19 years of age born preterm compared with their term-born peers.

METHOD

PubMed/MEDLINE, PsycINFO, and Cumulative Index to Nursing and Allied Health Literature electronic databases were searched (last updated in September 2019) using population ("child"), exposure ("preterm birth"), and outcome ("anxiety") terms for English peer-reviewed publications. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed with the risk of bias assessed using the Newcastle-Ottawa Quality Assessment Scale. Pooled odds ratio (OR) with 95% confidence intervals (CIs) was estimated using fixed-effects models.

RESULTS

Eleven independent studies met the inclusion criteria. The pooled sample comprised 1294 preterm and 1274 term-born children with anxiety outcomes and 777 preterm and 784 term-born children with depressive outcomes between 3 and 19 years of age. Children born preterm had significantly greater odds for anxiety (OR: 2.17; 95% CI, 1.43-3.29), generalized anxiety (OR: 2.20; 95% CI, 1.26-3.84), and specific phobia (OR: 1.93; 95% CI, 1.05-3.52) relative to their term-born peers. There were no significant between-group differences for reported depressive disorders.

CONCLUSION

Preterm birth is associated with a higher prevalence of anxiety, but not depressive disorders, from 3 to 19 years of age, suggesting distinct etiological pathways in this high-risk population. The findings support variation in the rates of specific anxiety diagnoses, indicating the need to extend neurodevelopmental surveillance to encompass a holistic emotional screening approach.

Association of Gestational Age at Birth With Brain Morphometry

IMPORTANCE

Preterm and postterm births are associated with adverse neuropsychiatric outcomes. However, it remains unclear whether variation of gestational age within the 37- to 42-week range of term deliveries is associated with neurodevelopment.

OBJECTIVE

To investigate the association of gestational age at birth (GAB) with structural brain morphometry in children aged 10 years.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study included pregnant women living in Rotterdam, the Netherlands, with an expected delivery date between April 1, 2002, and January 31, 2006. The study evaluated 3079 singleton children with GAB ranging from 26.3 to 43.3 weeks and structural neuroimaging at 10 years of age from the Generation R Study, a longitudinal, population-based prospective birth cohort from early pregnancy onward in Rotterdam. Data analysis was performed from March 1, 2019, to February 28, 2020, and at the time of the revision based on reviewer suggestions.

EXPOSURES

The GAB was calculated based on ultrasonographic assessment of crown-rump length (<12 weeks 5 days) or biparietal diameter (≥12 weeks 5 days) in dedicated research centers.

MAIN OUTCOMES AND MEASURES

Brain structure, including global and regional brain volumes and surface-based cortical measures (thickness, surface area, and gyrification), was quantified by magnetic resonance imaging.

RESULTS

In the 3079 children (1546 [50.2%] female) evaluated at 10 years of age, GAB was linearly associated with global and regional brain volumes. Longer gestational duration was associated with larger brain volumes; for example, every 1-week-longer gestational duration corresponded to an additional 4.5 cm3/wk (95% CI, 2.7-6.3 cm3/wk) larger total brain volume. These associations persisted when the sample was restricted to children born at term (GAB of 37-42 weeks: 4.8 cm3/wk; 95% CI, 1.8-7.7 cm3/wk). No evidence of nonlinear associations between GA and brain morphometry was observed.

CONCLUSIONS AND RELEVANCE

In this cohort study, gestational duration was linearly associated with brain morphometry during childhood, including within the window of term delivery. These findings may have marked clinical importance, particularly given the prevalence of elective cesarean deliveries.

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.

Trajectories of Overprotective Parenting and Hyperactivity-Impulsivity and Inattention Among Moderate-Late Preterm Children: A Population-Based Study

Parents of preterm children are more likely to adopt non-optimal parenting behaviors than parents of full-term (FT) children. However, there is a lack of studies on parents of children born moderate to late preterm (MLP; 32-36 gestational weeks). In this study, we aimed to examine: (1) the association between MLP birth status and the trajectory of parental overprotection throughout preschool years, and (2) the role of parental overprotection, MLP birth status, and their interaction in the prediction of the trajectories of hyperactivity-impulsivity and inattention throughout childhood. Data comes from a Canadian representative population-based cohort including 2028 FT, 100 MLP children, and their parents. Overprotective parenting was measured when children were 5, 17, and 29 months old. Hyperactivity-impulsivity and inattention symptoms were measured repeatedly from 4 to 8 years of age. Trajectories of parents' overprotectiveness and children's hyperactivity-impulsivity and inattention were modeled. MLP birth status was associated with an increase in parental overprotectiveness across the preschool period. MLP birth status and parental overprotection were both found to be associated with higher levels of hyperactivity-impulsivity symptoms across childhood. No interaction was found between birth status and parental overprotection. The results suggest that parents of MLP children become more overprotective across time compared to parents of FT children and that children born MLP and/or exposed to higher levels of parental overprotection demonstrated higher levels of hyperactivity-impulsivity symptoms across childhood.

Cortical Gray Matter Injury in Encephalopathy of Prematurity: Link to Neurodevelopmental Disorders

Preterm-born infants frequently suffer from an array of neurological damage, collectively termed encephalopathy of prematurity (EoP). They also have an increased risk of presenting with a neurodevelopmental disorder (e.g., autism spectrum disorder; attention deficit hyperactivity disorder) later in life. It is hypothesized that it is the gray matter injury to the cortex, in addition to white matter injury, in EoP that is responsible for the altered behavior and cognition in these individuals. However, although it is established that gray matter injury occurs in infants following preterm birth, the exact nature of these changes is not fully elucidated. Here we will review the current state of knowledge in this field, amalgamating data from both clinical and preclinical studies. This will be placed in the context of normal processes of developmental biology and the known pathophysiology of neurodevelopmental disorders. Novel diagnostic and therapeutic tactics required integration of this information so that in the future we can combine mechanism-based approaches with patient stratification to ensure the most efficacious and cost-effective clinical practice.

Sleep disturbance-related depressive symptom and brain volume reduction in shift-working nurses

Disturbed sleep is the most common effect of shift work. A large corpus of research indicates an association between sleep disturbance and depressive symptom in shift workers. In this study, we proposed the mediating role of grey matter (GM) structure in the relationship between sleep disturbance and depressive symptom. We collected structural MRI (sMRI) data as well as assessing the level of sleep disturbance and depressive symptom with the Pittsburgh Sleep disturbance Index and Zung Self-Rating Depression Scale, respectively, in 20 shift-working nurses and 19 day-working nurses. The shift-working nurses reported greater severity of sleep disturbance and depressive symptom, and furthermore, they exhibited reduced GM volume in the left postcentral gyrus (PostCG), right PostCG, right paracentral lobule, and left superior temporal gyrus (STG), compared to the day-working nurses. For each of the four brain regions, we formulated a mediation hypothesis by developing a mediation model that represents a causal chain between GM volume, sleep disturbance, and depressive symptom. Tests of the hypothesis on the mediation of GM volume revealed that inter-individual variations in left PostCG volume and left STG volume accounted for the influence of sleep disturbance on depressive symptom. These results suggest that structural alterations in PostCG and STG play an intervening role in the development of depressive symptom following sleep disturbance. We propose the need of considering neuroanatomical abnormalities in explaining and understanding symptomatic changes induced by sleep disturbance.

Environmental Influences on Infant Cortical Thickness and Surface Area

Cortical thickness (CT) and surface area (SA) vary widely between individuals and are associated with intellectual ability and risk for various psychiatric and neurodevelopmental conditions. Factors influencing this variability remain poorly understood, but the radial unit hypothesis, as well as the more recent supragranular cortex expansion hypothesis, suggests that prenatal and perinatal influences may be particularly important. In this report, we examine the impact of 17 major demographic and obstetric history variables on interindividual variation in CT and SA in a unique sample of 805 neonates who received MRI scans of the brain around 2 weeks of age. Birth weight, postnatal age at MRI, gestational age at birth, and sex emerged as important predictors of SA. Postnatal age at MRI, paternal education, and maternal ethnicity emerged as important predictors of CT. These findings suggest that individual variation in infant CT and SA is explained by different sets of environmental factors with neonatal SA more strongly influenced by sex and obstetric history and CT more strongly influenced by socioeconomic and ethnic disparities. Findings raise the possibility that interventions aimed at reducing disparities and improving obstetric outcomes may alter prenatal/perinatal cortical development.

What Do We Know About the Preterm Behavioral Phenotype? A Narrative Review

Preterm birth is associated with a significantly increased risk for childhood and adolescent psychopathology relative to full-term birth, with an inverse relationship between gestational age at birth and later risk for psychopathology. The manifestation of symptomatology and comorbidity profiles of emotional and behavioral adjustment problems in this high-risk group have been shown to be distinct from the broader pediatric population. Acknowledging these differences, a preterm behavioral phenotype has been proposed and increasingly recognized, highlighting the unique, frequent co-occurrence of symptomatology associated with attention-deficit/hyperactivity disorder, autism spectrum disorder, and anxiety disorders. The current state-of-the-art review provides a comprehensive characterization of this phenotype to date and further highlights key knowledge gaps primarily regarding the evolution of symptoms, co-occurrence of disorders and/or symptomatology within the phenotype, and associations of the phenotype with chronological age and degree of prematurity.

Born Too Early and Too Small: Higher Order Cognitive Function and Brain at Risk at Ages 8-16

Prematurity presents a risk for higher order cognitive functions. Some of these deficits manifest later in development, when these functions are expected to mature. However, the causes and consequences of prematurity are still unclear. We conducted a longitudinal study to first identify clinical predictors of ultrasound brain abnormalities in 196 children born very preterm (VP; gestational age ≤32 weeks) and with very low birth weight (VLBW; birth weight ≤1500 g). At ages 8-16, the subset of VP-VLBW children without neurological findings (124) were invited for a neuropsychological assessment and an MRI scan (41 accepted). Of these, 29 met a rigorous criterion for MRI quality and an age, and gender-matched control group (n = 14) was included in this study. The key findings in the VP-VLBW neonates were: (a) 37% of the VP-VLBW neonates had ultrasound brain abnormalities; (b) gestational age and birth weight collectively with hospital course (i.e., days in hospital, neonatal intensive care, mechanical ventilation and with oxygen therapy, surgeries, and retinopathy of prematurity) predicted ultrasound brain abnormalities. At ages 8-16, VP-VLBW children showed: a) lower intelligent quotient (IQ) and executive function; b) decreased gray and white matter (WM) integrity; (c) IQ correlated negatively with cortical thickness in higher order processing cortical areas. In conclusion, our data indicate that facets of executive function and IQ are the most affected in VP-VLBW children likely due to altered higher order cortical areas and underlying WM.

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.

Neurodevelopmental outcomes of the late preterm infant

Late preterm infants (born at 34^0/7-36^6/7 weeks gestation) have been found to have increased morbidity and mortality compared to full term infants. Research has also been done to explore longer-term neurodevelopmental outcomes. This review details neurodevelopmental outcomes from birth to adulthood for late preterm infants. Outcome studies indicate that they are at increased risk of developmental disability, school failure, behavior problems, social and medical disabilities, and death. Many questions still remain regarding late preterm infant neurodevelopmental outcomes and future research should be done into this topic. Given the high prevalence of late preterm births, even small differences in abilities, special education, and length of education may have broader consequences.

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.

Trajectories of brain development in school-age children born preterm with very low birth weight

Preterm birth (gestational age < 37 weeks) with very low birth weight (VLBW, birth weight ≤ 1500 g) is associated with lifelong cognitive deficits, including in executive function, and persistent alterations in cortical and subcortical structures. However, it remains unclear whether “catch-up” growth is possible in the preterm/VLBW brain. Longitudinal structural MRI was conducted with children born preterm with VLBW (n = 41) and term-born peers participating in the Norwegian Mother and Child Cohort Study (MoBa) (n = 128) at two timepoints in early school age (mean ages 8.0 and 9.3 years). Images were analyzed with the FreeSurfer 5.3.0 longitudinal stream to assess differences in development of cortical thickness, surface area, and brain structure volumes, as well as associations with executive function development (NEPSY Statue and WMS-III Spatial Span scores) and perinatal health markers. No longitudinal group × time effects in cortical thickness, surface area, or subcortical volumes were seen, indicating similar brain growth trajectories in the groups over an approximately 16-month period in middle childhood. Higher IQ scores within the VLBW group were associated with greater surface area in left parieto-occipital and inferior temporal regions. Among VLBW preterm-born children, cortical surface area was smaller across the cortical mantle, and cortical thickness was thicker occipitally and frontally and thinner in lateral parietal and posterior temporal areas. Smaller volumes of corpus callosum, right globus pallidus, and right thalamus persisted in the VLBW group from timepoint 1 to 2. VLBW children had on average IQ 1 SD below term-born MoBa peers and significantly worse scores on WMS-III Spatial Span. Executive function scores did not show differential associations with morphometry between groups cross-sectionally or longitudinally. This study investigated divergent or “catch-up” growth in terms of cortical thickness, surface area, and volumes of subcortical gray matter structures and corpus callosum in children born preterm/VLBW and did not find group × time interactions. Greater surface area at mean age 9.3 in left parieto-occipital and inferior temporal cortex was associated with higher IQ in the VLBW group. These results suggest that preterm VLBW children may have altered cognitive networks, yet have structural growth trajectories that appear generally similar to their term-born peers in this early school age window.

Behavioral and Socioemotional Development in Preterm Children

Prematurity is a significant risk factor for impaired neurodevelopmental outcomes. These include motor, cognitive, language, behavioral, and socioemotional competence. Long-term overall function depends on healthy socioemotional functioning. The vulnerability of the preterm brain during critical periods of development contributes to behavioral and socioemotional problems in preterm children. Attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) clinical features are more frequent in preterm children compared with their full-term counterparts; however, true rates of ASD and ADHD vary across studies. Early detection of behavioral and socioemotional problems in preterm children would enable timely early intervention to improve long-term functional outcomes.

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.

Effects of gestational age on brain volume and cognitive functions in generally healthy very preterm born children during school-age: A voxel-based morphometry study

Objective

To determine whether the relationship of gestational age (GA) with brain volumes and cognitive functions is linear or whether it follows a threshold model in preterm and term born children during school-age.

Study design

We studied 106 children (M = 10 years 1 month, SD = 16 months; 40 females) enrolled in primary school: 57 were healthy very preterm children (10 children born 24–27 completed weeks’ gestation (extremely preterm), 14 children born 28–29 completed weeks’ gestation, 19 children born 30–31 completed weeks’ gestation (very preterm), and 14 born 32 completed weeks’ gestation (moderately preterm)) all born appropriate for GA (AGA) and 49 term-born children. Neuroimaging involved voxel-based morphometry with the statistical parametric mapping software. Cognitive functions were assessed with the WISC-IV. General Linear Models and multiple regressions were conducted controlling age, sex, and maternal education.

Results

Compared to groups of children born 30 completed weeks’ gestation and later, children born <28 completed weeks’ gestation had less gray matter volume (GMV) and white matter volume (WMV) and poorer cognitive functions including decreased full scale IQ, and processing speed. Differences in GMV partially mediated the relationship between GA and full scale IQ in preterm born children.

Conclusions

In preterm children who are born AGA and without major complications GA is associated with brain volume and cognitive functions. In particular, decreased brain volume becomes evident in the extremely preterm group (born <28 completed weeks’ gestation). In preterm children born 30 completed weeks’ gestation and later the relationship of GA with brain volume and cognitive functions may be less strong as previously thought.

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.

[Early intellectual developmental outcome of late preterm infants]

OBJECTIVE

To investigate the early intellectual developmental outcome of late preterm infants.

METHODS

A total of 106 late preterm infants with a gestational age of 34-36⁺⁶ weeks who were admitted to the neonatal ward between January 2012 and January 2015, cured, discharged, and regularly followed up at the outpatient service for high-risk children were enrolled as the preterm group. A total of 120 healthy full-term infants during the same period were randomly selected as the term group. Neonatal behavioral neurological assessment (NBNA) was performed for late preterm infants at a corrected gestational age of 40 weeks and full-term infants at a gestational age of 40 weeks. The Gesell Developmental Scale was used for late preterm infants at a corrected age of 3, 6, and 12 months and full-term infants at an age of 3, 6, and 12 months.

RESULTS

The preterm group had an NBNA score of <37 and a significantly lower NBNA score than the term group (P<0.05). At the corrected age of 3 months, the preterm group had significantly lower scores of gross motor, fine motor, and social competence than the term group (P<0.05). At the corrected age of 6 months, the preterm group had significantly lower scores of adaptability, gross motor, and fine motor than the term group (P<0.05). At the corrected age of 12 months, the preterm group had significantly lower scores of adaptability, gross motor, and social competence than the term group (P<0.05).

CONCLUSIONS

Late preterm infants have early intellectual developmental delay. It is necessary to perform neurodevelopmental monitoring for late preterm infants.

Altered resting-state functional connectivity in emotion-processing brain regions in adults who were born very preterm

BACKGROUND

Very preterm birth (VPT; <32 weeks of gestation) has been associated with impairments in emotion regulation, social competence and communicative skills. However, the neuroanatomical mechanisms underlying such impairments have not been systematically studied. Here we investigated the functional integrity of the amygdala connectivity network in relation to the ability to recognize emotions from facial expressions in VPT adults.

METHOD

Thirty-six VPT-born adults and 38 age-matched controls were scanned at rest in a 3-T MRI scanner. Resting-state functional connectivity (rs-fc) was assessed with SPM8. A seed-based analysis focusing on three amygdalar subregions (centro-medial/latero-basal/superficial) was performed. Participants' ability to recognize emotions was assessed using dynamic stimuli of human faces expressing six emotions at different intensities with the Emotion Recognition Task (ERT).

RESULTS

VPT individuals compared to controls showed reduced rs-fc between the superficial subregion of the left amygdala, and the right posterior cingulate cortex (p = 0.017) and the left precuneus (p = 0.002). The VPT group further showed elevated rs-fc between the left superficial amygdala and the superior temporal sulcus (p = 0.008). Performance on the ERT showed that the VPT group was less able than controls to recognize anger at low levels of intensity. Anger scores were significantly associated with rs-fc between the superficial amygdala and the posterior cingulate cortex in controls but not in VPT individuals.

CONCLUSIONS

These findings suggest that alterations in rs-fc between the amygdala, parietal and temporal cortices could represent the mechanism linking VPT birth and deficits in emotion processing.

Developmental Outcomes of Late Preterm Infants From Infancy to Kindergarten

OBJECTIVE

To compare developmental outcomes of late preterm infants (34-36 weeks' gestation) with infants born at early term (37-38 weeks' gestation) and term (39-41 weeks' gestation), from infancy through kindergarten.

METHODS

Sample included 1000 late preterm, 1800 early term, and 3200 term infants ascertained from the Early Childhood Longitudinal Study, Birth Cohort. Direct assessments of development were performed at 9 and 24 months by using the Bayley Short Form-Research Edition T-scores and at preschool and kindergarten using the Early Childhood Longitudinal Study, Birth Cohort reading and mathematics θ scores. Maternal and infant characteristics were obtained from birth certificate data and parent questionnaires. After controlling for covariates, we compared mean developmental outcomes between late preterm and full-term groups in serial cross-sectional analyses at each timepoint using multilinear regression, with pairwise comparisons testing for group differences by gestational age categories.

RESULTS

With covariates controlled at all timepoints, at 9 months late preterm infants demonstrated less optimal developmental outcomes (T = 47.31) compared with infants born early term (T = 49.12) and term (T = 50.09) (P < .0001). This association was not seen at 24 months, (P = .66) but reemerged at preschool. Late preterm infants demonstrated less optimal scores in preschool reading (P = .0006), preschool mathematics (P = .0014), and kindergarten reading (P = .0007) compared with infants born at term gestation.

CONCLUSIONS

Although late preterm infants demonstrate comparable developmental outcomes to full-term infants (early term and full-term gestation) at 24 months, they demonstrate less optimal reading outcomes at preschool and kindergarten timepoints. Ongoing developmental surveillance for late preterm infants is warranted into preschool and kindergarten.

Altered brain function, structure, and developmental trajectory in children born late preterm

BACKGROUND

Late preterm birth (34-36 wk gestation) is a common occurrence with potential for altered brain development.

METHODS

This observational cohort study compared children at age 6-13 y based on the presence or absence of the historical risk factor of late preterm birth. Children completed a battery of cognitive assessments and underwent magnetic resonance imaging of the brain.

RESULTS

Late preterm children (n = 52) demonstrated slower processing speed (P = 0.035) and scored more poorly in visual-spatial perception (P = 0.032) and memory (P = 0.007) than full-term children (n = 74). Parents of late preterm children reported more behavioral difficulty (P = 0.004). There were no group differences in cognitive ability or academic achievement. Imaging revealed similar intracranial volumes but less total tissue and more cerebrospinal fluid (P = 0.004) for late preterm children compared to full-term children. The tissue difference was driven by differences in the cerebrum (P = 0.028) and distributed across cortical (P = 0.051) and subcortical tissue (P = 0.047). Late preterm children had a relatively smaller thalamus (P = 0.012) than full-term children. Only full-term children demonstrated significant decreases in cortical tissue volume (P < 0.001) and thickness (P < 0.001) with age.

CONCLUSION

Late preterm birth may affect cognition, behavior, and brain structure well beyond infancy.

Common mental disorders in young adults born late-preterm

BACKGROUND

Results of adulthood mental health of those born late-preterm (34 + 0-36 + 6 weeks + days of gestation) are mixed and based on national registers. We examined if late-preterm birth was associated with a higher risk for common mental disorders in young adulthood when using a diagnostic interview, and if this risk decreased as gestational age increased.

METHOD

A total of 800 young adults (mean = 25.3, s.d. = 0.62 years), born 1985-1986, participated in a follow-up of the Arvo Ylppö Longitudinal Study. Common mental disorders (mood, anxiety and substance use disorders) during the past 12 months were defined using the Composite International Diagnostic Interview (Munich version). Gestational age was extracted from hospital birth records and categorized into early-preterm (<34 + 0, n = 37), late-preterm (34 + 0-36 + 6, n = 106), term (37 + 0-41 + 6, n = 617) and post-term (⩾42 + 0, n = 40).

RESULTS

Those born late-preterm and at term were at a similar risk for any common mental disorder [odds ratio (OR) 1.11, 95% confidence interval (CI) 0.67-1.84], for mood (OR 1.11, 95% CI 0.54-2.25), anxiety (OR 1.00, 95% CI 0.40-2.50) and substance use (OR 1.31, 95% CI 0.74-2.32) disorders, and co-morbidity of these disorders (p = 0.38). While the mental disorder risk decreased significantly as gestational age increased, the trend was driven by a higher risk in those born early-preterm.

CONCLUSIONS

Using a cohort born during the advanced neonatal and early childhood care, we found that not all individuals born preterm are at risk for common mental disorders in young adulthood - those born late-preterm are not, while those born early-preterm are at a higher risk. Available resources for prevention and intervention should be targeted towards the preterm group born the earliest.

Brain Volumes at Term-Equivalent Age Are Associated with 2-Year Neurodevelopment in Moderate and Late Preterm Children

OBJECTIVE

To explore the association between brain maturation, injury, and volumes at term-equivalent age with 2-year development in moderate and late preterm children.

STUDY DESIGN

Moderate and late preterm infants were recruited at birth and assessed at age 2 years using the Bayley Scales of Infant and Toddler Development, Third Edition. Brain magnetic resonance imaging (MRI) was performed at term-equivalent age and qualitatively assessed for brain maturation (myelination of the posterior limb of the internal capsule and gyral folding) and injury. Brain volumes were measured using advanced segmentation techniques. The associations between brain MRI measures with developmental outcomes were explored using linear regression analyses.

RESULTS

A total of 197 children underwent MRI and assessed using the Bayley Scales of Infant and Toddler Development, Third Edition. Larger total brain tissue volumes were associated with higher cognitive and language scores (adjusted coefficients per 10% increase in brain size; 95% CI of 3.2 [0.4, 5.6] and 5.6 [2.4, 8.8], respectively). Similar relationships were documented for white matter volumes with cognitive and language scores, multiple cerebral structures with language scores, and cerebellar volumes with motor scores. Larger cerebellar volumes were independently associated with better language and motor scores, after adjustment for other perinatal factors. There was little evidence of relationships between myelination of the posterior limb of the internal capsule, gyral folding, or injury with 2-year development.

CONCLUSIONS

Larger total brain tissue, white matter, and cerebellar volumes at term-equivalent age are associated with better neurodevelopment in moderate and late preterm children. Brain volumes may be an important marker for neurodevelopmental deficits described in moderate and late preterm children.

Altered Amygdala Development and Fear Processing in Prematurely Born Infants

Context: Prematurely born children have a high risk of developmental and behavioral disabilities. Cerebral abnormalities at term age have been clearly linked with later behavior alterations, but existing studies did not focus on the amygdala. Moreover, studies of early amygdala development after premature birth in humans are scarce.

Objective: To compare amygdala volumes in very preterm infants at term equivalent age (TEA) and term born infants, and to relate premature infants’ amygdala volumes with their performance on the Laboratory Temperament Assessment Battery (Lab-TAB) fear episode at 12 months.

Participants: Eighty one infants born between 2008 and 2014 at the University Hospitals of Geneva and Lausanne, taking part in longitudinal and functional imaging studies, who had undergone a magnetic resonance imaging (MRI) scan at TEA enabling manual amygdala delineation.

Outcomes: Amygdala volumes assessed by manual segmentation of MRI scans; volumes of cortical and subcortical gray matter, white matter and cerebrospinal fluid (CSF) automatically segmented in 66 infants; scores for the Lab-TAB fear episode for 42 premature infants at 12 months.

Results: Amygdala volumes were smaller in preterm infants at TEA than term infants (mean difference 138.03 mm³, p < 0.001), and overall right amygdala volumes were larger than left amygdala volumes (mean difference 36.88 mm³, p < 0.001). White matter volumes were significantly smaller (p < 0.001) and CSF volumes significantly larger (p < 0.001) in preterm than in term born infants, while cortical and subcortical gray matter volumes were not significantly different between groups. Amygdala volumes showed significant correlation with the intensity of the escape response to a fearsome toy (r_s = 0.38, p = 0.013), and were larger in infants showing an escape response compared to the infants showing no escape response (mean difference 120.97 mm³, p = 0.005). Amygdala volumes were not significantly correlated with the intensity of facial fear, distress vocalizations, bodily fear and positive motor activity in the fear episode.

Conclusion: Our results indicate that premature birth is associated with a reduction in amygdala volumes and white matter volumes at TEA, suggesting that altered amygdala development might be linked to alterations in white matter connectivity reported in premature infants. Moreover, our data suggests that such alterations might affect infants’ fear-processing capabilities.

Socio-Emotional Development Following Very Preterm Birth: Pathways to Psychopathology

Very preterm birth (VPT; < 32 weeks of gestation) has been associated with an increased risk to develop cognitive and socio-emotional problems, as well as with increased vulnerability to psychiatric disorder, both with childhood and adult onset. Socio-emotional impairments that have been described in VPT individuals include diminished social competence and self-esteem, emotional dysregulation, shyness and timidity. However, the etiology of socio-emotional problems in VPT samples and their underlying mechanisms are far from understood. To date, research has focused on the investigation of both biological and environmental risk factors associated with socio-emotional problems, including structural and functional alterations in brain areas involved in processing emotions and social stimuli, perinatal stress and pain and parenting strategies. Considering the complex interplay of the aforementioned variables, the review attempts to elucidate the mechanisms underlying the association between very preterm birth, socio-emotional vulnerability and psychopathology. After a comprehensive overview of the socio-emotional impairments associated with VPT birth, three main models of socio-emotional development are presented and discussed. These focus on biological vulnerability, early life adversities and parenting, respectively. To conclude, a developmental framework is used to consider different pathways linking VPT birth to psychopathology, taking into account the interaction between medical, biological, and psychosocial factors.