Neonatal brain microstructure correlates of neurodevelopment and gait in preterm children 18-22 mo of age: an MRI and DTI study

Beyond motor learning: Insights from infant magnetic resonance imaging on the critical role of the cerebellum in behavioral development

Although the cerebellum is now recognized for its crucial role in non-motor functions such as language, perceptual processes, social communication, and executive function in adults, it is often overlooked in studies of non-motor behavioral development in infancy. Recent magnetic resonance imaging (MRI) research increasingly shows the cerebellum is key to understanding the emergence of complex human behaviors and neurodevelopmental conditions. This review summarizes studies from diverse MRI modalities that link early cerebellar development from birth to age two with emerging non-motor behaviors and psychiatric symptomatology. Our focus centered on both term and preterm infants, excluding studies of perinatal injury and cerebellar pathology. We conclude that the cerebellum is implicated in many non-motor behaviors and implicit learning mechanisms in infancy. The field's current limitations include inconsistencies in study design, a paucity of gold-standard infant neuroimaging tools, and treatment of the cerebellum as a uniform structure. Moving forward, the cerebellum should be considered a structure of greater interest to the developmental neuroimaging community. Studies should test developmental hypotheses about the behavioral roles of specific cerebro-cerebellar circuits, and theoretical frameworks such as Olson's "model switch" hypothesis of cerebellar learning. Large-scale, longitudinal, well-powered neuroimaging studies of typical and preterm development will be key.

Brain development using a multicomponent intravenous lipid emulsion in preterm infants

BACKGROUND

Intravenous lipid emulsions are an essential component of nutritional support for very preterm infants. Many neonatal intensive care units have transitioned from traditional soybean oil-only to fish oil-containing multicomponent lipid emulsions, but the neurodevelopmental implications have not been well-explored. The primary aim of this study was to assess extrauterine third trimester brain growth in very preterm infants supported with soybean oil-only compared to fish-oil containing multicomponent lipid emulsions; white matter development and neurobehavioral regulation at term were also investigated.

METHODS

Human milk-fed very preterm infants (born less than or equal to 32 weeks' gestation) receiving either soybean oil-only (before 2019) or multicomponent (after 2019) lipid emulsions underwent quantitative brain MRI (volumetric growth and white matter development) and neurodevelopmental assessment (Neonatal Intensive Care Unit Network Neurobehavioral Scale) at term-equivalent age. Analyses were adjusted for age at birth and term assessments, as well as clinically significant covariates.

RESULTS

92 infants (61 soybean, 31 multicomponent) were included (mean [SD] birth gestational age: 27.3 [2.3] weeks). Soybean oil-only infants demonstrated smaller brainstem volumes (β [95% CI] = -0.5 [-0.8,-0.1], p = .007); additionally less mature white matter development (mean diffusivity [MD, mm2/second x10- 3] and fractional anisotropy [FA]) in the corpus callosum (MD genu: β = 0.10 [0.01, 0.20], p = .04; splenium: β = 0.14 [0.04, 0.24], p = .006), posterior limbs of internal capsule (MD right (R): β = 0.05 [0.02, 0.08], p = .004, left (L): β = 0.04 [0.01, 0.08], p = .01; FA R: β = -0.03 [-0.06, -0.00], p = .03), and brainstem (FA R: β = 0.07 [0.04, 0.10], p < .001, L: β = 0.05 [0.02, 0.09], p = .002); and lower quality of movement (β = -0.54 [-0.97, -0.11], p = .02) and higher state-related stress (β = 1.41 [0.14, 2.83], p = .04).

CONCLUSIONS

Very preterm infants supported with a fish-oil containing multicomponent compared to soybean oil-only lipid emulsion demonstrated improved regional brain growth, as well as evidence of enhanced white matter microstructural organization and neurobehavioral regulation, at term corrected age.

TRIAL REGISTRATION

Clinical trial number: Not applicable.

Neuromuscular impairments of cerebral palsy: contributions to gait abnormalities and implications for treatment

Identification of neuromuscular impairments in cerebral palsy (CP) is essential to providing effective treatment. However, clinical recognition of neuromuscular impairments in CP and their contribution to gait abnormalities is limited, resulting in suboptimal treatment outcomes. While CP is the most common childhood movement disorder, clinical evaluations often do not accurately identify and delineate the primary neuromuscular and secondary musculoskeletal impairments or their specific impact on mobility. Here we discuss the primary neuromuscular impairments of CP that arise from early brain injury and the progressive secondary musculoskeletal impairments, with a focus on spastic CP, the most common form of CP. Spastic CP is characterized by four primary interrelated neuromuscular impairments: 1. muscle weakness, 2. short muscle-tendon units due to slow muscle growth relative to skeletal growth, 3. muscle spasticity characterized by increased sensitivity to stretch, and 4. impaired selective motor control including flexor and extensor muscle synergies. Specific gait events are affected by the four primary neuromuscular impairments of spastic CP and their delineation can improve evaluation to guide targeted treatment, prevent deformities and improve mobility. Emerging information on neural correlates of neuromuscular impairments in CP provides the clinician with a more complete context with which to evaluate and develop effective treatment plans. Specifically, addressing the primary neuromuscular impairments and reducing secondary musculoskeletal impairments are important treatment goals. This perspective on neuromuscular mechanisms underlying gait abnormalities in spastic CP aims to inform clinical evaluation of CP, focus treatment more strategically, and guide research priorities to provide targeted treatments for CP.

A unique cerebellar pattern of microglia activation in a mouse model of encephalopathy of prematurity

Preterm infants often show pathologies of the cerebellum, which are associated with impaired motor performance, lower IQ and poor language skills at school ages. Using a mouse model of inflammation-induced encephalopathy of prematurity driven by systemic administration of pro-inflammatory IL-1β, we sought to uncover causes of cerebellar damage. In this model, IL-1β is administered between postnatal day (P) 1 to day 5, a timing equivalent to the last trimester for brain development in humans. Structural MRI analysis revealed that systemic IL-1β treatment induced specific reductions in gray and white matter volumes of the mouse cerebellar lobules I and II (5% false discovery rate [FDR]) from P15 onwards. Preceding these MRI-detectable cerebellar volume changes, we observed damage to oligodendroglia, with reduced proliferation of OLIG2+ cells at P10 and reduced levels of the myelin proteins myelin basic protein (MBP) and myelin-associated glycoprotein (MAG) at P10 and P15. Increased density of IBA1+ cerebellar microglia were observed both at P5 and P45, with evidence for increased microglial proliferation at P5 and P10. Comparison of the transcriptome of microglia isolated from P5 cerebellums and cerebrums revealed significant enrichment of pro-inflammatory markers in microglia from both regions, but cerebellar microglia displayed a unique type I interferon signaling dysregulation. Collectively, these data suggest that perinatal inflammation driven by systemic IL-1β leads to specific cerebellar volume deficits, which likely reflect oligodendrocyte pathology downstream of microglial activation. Further studies are now required to confirm the potential of protective strategies aimed at preventing sustained type I interferon signaling driven by cerebellar microglia as an important therapeutic target.

Altered microstructure of the splenium of corpus callosum is associated with neurodevelopmental impairment in preterm infants with necrotizing enterocolitis

Background

Necrotizing enterocolitis (NEC) is a devastating disease in preterm infants with significant morbidities, including neurodevelopmental impairment (NDI). This study aimed to investigate whether NEC is associated with (1) brain volume expansion and white matter maturation using diffusion tensor imaging analysis and (2) NDI compared with preterm infants without NEC.

Methods

We included 86 preterm infants (20 with NEC and 66 without NEC) with no evidence of brain abnormalities on trans-fontanelle ultrasonography and magnetic resonance imaging at term-equivalent age (TEA). Regional brain volume analysis and white matter tractography were performed to study brain microstructure alterations. NDI was assessed using the Bayley Scales of Infant and Toddler Development-III (BSID-III) at 18 months of corrected age (CA).

Results

Preterm infants with NEC showed significantly high risk of motor impairment (odds ratio 58.26, 95% confidence interval 7.80–435.12, p < 0.001). We found significantly increased mean diffusivity (MD) in the splenium of corpus callosum (sCC) (p = 0.001) and the left corticospinal tract (p = 0.001) in preterm infants with NEC. The sCC with increased MD showed a negative association with the BSID-III language (p = 0.025) and motor scores (p = 0.002) at 18 months of CA, implying the relevance of sCC integrity with later NDI.

Conclusion

The white matter microstructure differed between preterm infants with and without NEC. The prognostic value of network parameters of sCC at TEA may provide better information for the early detection of NDI in preterm infants.

The Effects of Preterm Birth on Musculoskeletal Health-Related Disorders

Preterm birth is associated with various diseases and conditions which demand multidisciplinary medical care. Approximately 10% of all neonates are born prematurely with an increasing survival rate in almost all Western countries. This ongoing, yet desirable trend is creating new challenges for sufficient medical treatment regimens, which should be upheld throughout the patients' lives. Orthopedic surgeons are focused on musculoskeletal disorders and the improvement of patients' ability to cope with the challenges of everyday life. The most common conditions associated with preterm birth are cerebral palsy and a dysregulation of the calcium/phosphorus metabolism, which may lead to fractures. These diseases may vary greatly in their organic manifestation and clinical presentation. This demands multidisciplinary cooperation and parental support. Clinical management is aimed on the early enhancement of a patient's physical, as well as neurological condition, and to prevent the development of secondary musculoskeletal disorders. In this article, we give an overview of the current literature on the most common musculoskeletal disorders associated with preterm birth and critically discuss state of the art diagnostic standards and treatment algorithms.

Early micro- and macrostructure of sensorimotor tracts and development of cerebral palsy in high risk infants

Infants born very preterm (VPT) are at high risk of motor impairments such as cerebral palsy (CP), and diagnosis can take 2 years. Identifying in vivo determinants of CP could facilitate presymptomatic detection and targeted intervention. Our objectives were to derive micro‐ and macrostructural measures of sensorimotor white matter tract integrity from diffusion MRI at term‐equivalent age, and determine their association with early diagnosis of CP. We enrolled 263 VPT infants (≤32 weeks gestational age) as part of a large prospective cohort study. Diffusion and structural MRI were acquired at term. Following consensus guidelines, we defined early diagnosis of CP based on abnormal structural MRI at term and abnormal neuromotor exam at 3–4 months corrected age. Using Constrained Spherical Deconvolution, we derived a white matter fiber orientation distribution (fOD) for subjects, performed probabilistic whole‐brain tractography, and segmented nine sensorimotor tracts of interest. We used the recently developed fixel‐based (FB) analysis to compute fiber density (FD), fiber‐bundle cross‐section (FC), and combined fiber density and cross‐section (FDC) for each tract. Of 223 VPT infants with high‐quality diffusion MRI data, 14 (6.3%) received an early diagnosis of CP. The cohort's mean (SD) gestational age was 29.4 (2.4) weeks and postmenstrual age at MRI scan was 42.8 (1.3) weeks. FD, FC, and FDC for each sensorimotor tract were significantly associated with early CP diagnosis, with and without adjustment for confounders. Measures of sensorimotor tract integrity enhance our understanding of white matter changes that antecede and potentially contribute to the development of CP in VPT infants.

Lipid Intake and Neurodevelopment in Preterm Infants

Preterm infants are born before the critical period of lipid accretion and brain development that occurs during the third trimester of pregnancy. Dietary lipids serve as an important source of energy and are involved in complex processes that are essential for normal central nervous system development. In addition to traditional neurodevelopmental testing, novel quantitative magnetic resonance imaging (MRI) techniques are now available to evaluate the impact of nutritional interventions on early preterm brain development. Trials of long-chain polyunsaturated fatty acid supplementation have yielded inconsistent effects on neurodevelopmental outcomes and quantitative MRI findings. Recent studies using quantitative MRI suggest a positive impact of early lipid intake on brain volumes and white matter microstructural organization by term-equivalent age.

Sexual Dimorphisms and Asymmetries of the Thalamo-Cortical Pathways and Subcortical Grey Matter of Term Born Healthy Neonates: An Investigation with Diffusion Tensor MRI

Diffusion-tensor-MRI was performed on 28 term born neonates. For each hemisphere, we quantified separately the axial and the radial diffusion (AD, RD), the apparent diffusion coefficient (ADC) and the fractional anisotropy (FA) of the thalamo-cortical pathway (THC) and four structures: thalamus (TH), putamen (PT), caudate nucleus (CN) and globus-pallidus (GP). There was no significant difference between boys and girls in either the left or in the right hemispheric THC, TH, GP, CN and PT. In the combined group (boys + girls) significant left greater than right symmetry was observed in the THC (AD, RD and ADC), and TH (AD, ADC). Within the same group, we reported left greater than right asymmetry in the PT (FA), CN (RD and ADC). Different findings were recorded when we split the group of neonates by gender. Girls exhibited right > left AD, RD and ADC in the THC and left > right FA in the PT. In the group of boys, we observed right > left RD and ADC. We also reported left > right FA in the PT and left > right RD in the CN. These results provide insights into normal asymmetric development of sensory-motor networks within boys and girls.

Delayed Maturation of the Middle Cerebellar Peduncles at Near-Term Age Predicts Abnormal Neurodevelopment in Preterm Infants

BACKGROUND

The infant brain grows quickly with elaborate microstructural development during the neonatal period. The white matter, during critical periods of development, is selectively vulnerable to altered maturation and impaired growth in very-low-birth-weight (VLBW) infants.

OBJECTIVE

To evaluate whether abnormal white matter maturation in VLBW infants is associated with poor neurodevelopmental outcomes at 18 months of corrected age.

METHODS

Between 2015 and 2017, we recruited 60 VLBW infants at 24-32 weeks of gestational age and 15 full-term controls. All participants underwent magnetic resonance imaging at near-term age and were assessed at 18 months of corrected age with the Bayley Scales of Infant and Toddler Development, Third Edition. The associations between regional white matter fractional anisotropy (FA) and mean diffusivity on diffusion tensor imaging (DTI) and developmental outcomes were explored using multivariable linear regression after correcting for gestational age, postmenstrual age at DTI scan, and maternal education level.

RESULTS

The FA values of the splenium of the corpus callosum (p = 0.032), corticospinal tract (p = 0.025), middle cerebellar peduncle (MCP) (p < 0.001), and cingulum (p = 0.043) were significantly related to cognitive scores; however, only the association corresponding to the MCP remained significant after correcting for multiple comparisons. The MCP FA (p = 0.008) was associated with motor scores after correction for multiple comparisons (p = 0.008). Cognitive impairment (area under the curve [AUC] = 0.823, 95% confidence interval [CI] = 0.722-0.911) and motor impairment (AUC = 0.776, 95% CI = 0.656-0.899) were predicted by MCP FA.

CONCLUSIONS

The FA of MCP at near-term age may predict developmental outcomes of VLBW infants at 18 months of corrected age.

The cingulum in very preterm infants relates to language and social-emotional impairment at 2 years of term-equivalent age

•

Maturation of specific WM tracts in preterm individuals differs from those of term controls.

•

The elastic net logistic regression model was used to identify altered white matter tracts in the preterm brain.

•

The alteration of the cingulum in the preterm at near-term correlate with neurodevelopmental scores at 18–22 months of age.

Background

Relative to full-term infants, very preterm infants exhibit disrupted white matter (WM) maturation and problems related to development, including motor, cognitive, social-emotional, and receptive and expressive language processing.

Objective

The present study aimed to determine whether regional abnormalities in the WM microstructure of very preterm infants, as defined relative to those of full-term infants at a near-term age, are associated with neurodevelopmental outcomes at the age of 18–22 months.

Methods

We prospectively enrolled 89 very preterm infants (birth weight < 1500 g) and 43 normal full-term control infants born between 2016 and 2018. All infants underwent a structural brain magnetic resonance imaging scan at near-term age. The diffusion tensor imaging (DTI) metrics of the whole-brain WM tracts were extracted based on the neonatal probabilistic WM pathway. The elastic net logistic regression model was used to identify altered WM tracts in the preterm brain. We evaluated the associations between the altered WM microstructure at near-term age and motor, cognitive, social-emotional, and receptive and expressive language developments at 18–22 months of age, as measured using the Bayley Scales of Infant Development, Third Edition.

Results

We found that the elastic net logistic regression model could classify preterm and full-term neonates with an accuracy of 87.9% (corrected p < 0.008) using the DTI metrics in the pathway of interest with a 10% threshold level. The fractional anisotropy (FA) values of the body and splenium of the corpus callosum, middle cerebellar peduncle, left and right uncinate fasciculi, and right portion of the pathway between the premotor and primary motor cortices (premotor-PMC), as well as the mean axial diffusivity (AD) values of the left cingulum, were identified as contributive features for classification. Increased adjusted AD values in the left cingulum pathway were significantly correlated with language scores after false discovery rate (FDR) correction (r = 0.217, p = 0.043). The expressive language and social-emotional composite scores showed a significant positive correlation with the AD values in the left cingulum pathway (r = 0.226 [p = 0.036] and r = 0.31 [p = 0.003], respectively) after FDR correction.

Conclusion

Our approach suggests that the cingulum pathways of very preterm infants differ from those of full-term infants and significantly contribute to the prediction of the subsequent development of the language and social-emotional domains. This finding could improve our understanding of how specific neural substrates influence neurodevelopment at later ages, and individual risk prediction, thus helping to inform early intervention strategies that address developmental delay.

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.

Neonatal white matter tract microstructure and 2-year language outcomes after preterm birth

•

Preterm infant white matter tracts uniquely predict later toddler language.

•

Neonatal medical history moderates posterior corpus callosum–language relations.

•

Different associations by tract may relate to brain maturation and medical history.

Aim

To determine whether variability in diffusion MRI (dMRI) white matter tract metrics, obtained in a cohort of preterm infants prior to neonatal hospital discharge, would be associated with language outcomes at age 2 years, after consideration of age at scan and number of major neonatal complications.

Method

30 children, gestational age 28.9 (2.4) weeks, underwent dMRI at mean post menstrual age 36.4 (1.4) weeks and language assessment with the Bayley Scales of Infant Development–III at mean age 22.2 (1.7) months chronological age. Mean fractional anisotropy (FA) and mean diffusivity (MD) were calculated for 5 white matter tracts. Hierarchical linear regression assessed associations between tract FA, moderating variables, and language outcomes.

Results

FA of the left inferior longitudinal fasciculus accounted for 17% (p = 0.03) of the variance in composite language and FA of the posterior corpus callosum accounted for 19% (p = 0.02) of the variance in composite language, beyond that accounted for by post-menstrual age at scan and neonatal medical complications. The number of neonatal medical complications moderated the relationship between language and posterior corpus callosum FA but did not moderate the association in the other tract.

Conclusion

Language at age 2 is associated with white matter metrics in early infancy in preterm children. The different pattern of associations by fiber group may relate to the stage of brain maturation and/or the nature and timing of medical complications related to preterm birth. Future studies should replicate these findings with a larger sample size to assure reliability of the findings.

Improved brain growth and microstructural development in breast milk-fed very low birth weight premature infants

AIM

Breast milk feeding is linked to improved neurodevelopmental outcomes in very low birth weight (VLBW) infants, though the mechanisms are not well understood. This study utilised quantitative magnetic resonance imaging (qMRI) techniques to compare brain growth and white matter development in preterm infants receiving primarily breast milk versus formula feeds.

METHODS

We prospectively enrolled infants born at very low birth weight (<1500 g) and <32 weeks gestational age and performed MRI at term-equivalent age. We utilised volumetric segmentation to calculate regional and total brain volumes and diffusion tensor imaging to evaluate white matter microstructural organisation. Daily nutritional data were extracted from the medical record.

RESULTS

Nutritional and MRI data were obtained for 68 infants admitted within the first week of life (44 breast milk and 24 formula). Breast milk-fed infants demonstrated significantly larger total brain volumes (P = .04) as well as volumes in the amygdala-hippocampus and cerebellum (P < .01) compared with formula-fed. Infants receiving breast milk also demonstrated greater white matter microstructural organisation in the corpus callosum, posterior limb of internal capsule and cerebellum (P < .01 to .03).

CONCLUSION

VLBW infants receiving primarily breast milk versus preterm formula in this small exploratory study demonstrated significantly greater regional brain volumes and white matter microstructural organisation by term-equivalent age.

Structural Brain Lesions and Gait Pathology in Children With Spastic Cerebral Palsy

The interaction between brain damage and motor function is not yet fully understood in children with spastic cerebral palsy (CP). Therefore, a semi-quantitative MRI (sqMRI) scale was used to explore whether identified brain lesions related to functional abilities and gait pathology in this population. A retrospective cohort of ambulatory children with spastic CP was selected [N = 104; 52 bilateral (bCP) and 52 unilateral (uCP)]. Extent and location-specific scores were defined according to the sqMRI scale guidelines. The gross motor function classification system (GMFCS), the gait profile score (GPS), GPSs per motion plane, gait variable scores (GVS) and multiple-joint (MJ) gait patterns were related to brain lesion scores. In all groups, the global total brain scores correlated to the GPS (total: r_s = 0.404, p ≤ 0.001; bCP: r_s = 0.335, p ≤ 0.05; uCP: r_s = 0.493, p ≤ 0.001). The global total hemispheric scores correlated to the GMFCS (total: r_s = 0.392, p ≤ 0.001; bCP: r_s = 0.316, p ≤ 0.05; uCP: r_s = 0.331, p ≤ 0.05). The laterality scores of the hemispheres in the total group correlated negatively to the GMFCS level (r_s = −0.523, p ≤ 0.001) and the GVS-knee sagittal (r_s = −0.311, p ≤ 0.01). Lesion location, for the total group demonstrated positive correlations between parietal lobe involvement and the GPS (r_s = 0.321, p ≤ 0.001) and between periventricular layer damage and the GMFCS (r_s = 0.348, p ≤ 0.001). Involvement of the anterior part of the corpus callosum (CC) was associated with the GVS-hip sagittal in all groups (total: r_pb = 0.495, p ≤ 0.001; bCP: r_pb = 0.357, p ≤ 0.05; uCP: r_pb = 0.641, p ≤ 0.001). The global total hemispheric and laterality of the hemispheres scores differentiated between the minor and both the extension (p ≤ 0.001 and p ≤ 0.001) and flexion (p = 0.016 and p = 0.013, respectively) MJ patterns in the total group. Maximal periventricular involvement and CC intactness were associated with extension patterns (p ≤ 0.05 and p ≤ 0.001, respectively). Current findings demonstrated relationships between brain structure and motor function as well as pathological gait, in this cohort of children with CP. These results might facilitate the timely identification of gait pathology and, ultimately, guide individualized treatment planning of gait impairments in children with CP.

Neonatal Brain Microstructure and Machine-Learning-Based Prediction of Early Language Development in Children Born Very Preterm

BACKGROUND

Very-low-birth-weight preterm infants have a higher rate of language impairments compared with children born full term. Early identification of preterm infants at risk for language delay is essential to guide early intervention at the time of optimal neuroplasticity. This study examined near-term structural brain magnetic resonance imaging (MRI) and white matter microstructure assessed on diffusion tensor imaging (DTI) in relation to early language development in children born very preterm.

METHODS

A total of 102 very-low-birth-weight neonates (birthweight≤1500g, gestational age ≤32-weeks) were recruited to participate from 2010 to 2011. Near-term structural MRI was evaluated for white matter and cerebellar abnormalities. DTI fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity were assessed. Language development was assessed with Bayley Scales of Infant-Toddler Development-III at 18 to 22 months adjusted age. Multivariate models with leave-one-out cross-validation and exhaustive feature selection identified three brain regions most predictive of language function. Distinct logistic regression models predicted high-risk infants, defined by language scores >1 S.D. below average.

RESULTS

Of 102 children, 92 returned for neurodevelopmental testing. Composite language score mean ± S.D. was 89.0 ± 16.0; 31 of 92 children scored <85, including 15 of 92 scoring <70, suggesting moderate-to-severe delay. Children with cerebellar asymmetry had lower receptive language subscores (P = 0.016). Infants at high risk for language impairments were predicted based on regional white matter microstructure on DTI with high accuracy (sensitivity, specificity) for composite (89%, 86%), expressive (100%, 90%), and receptive language (100%, 90%).

CONCLUSIONS

Multivariate models of near-term structural MRI and white matter microstructure on DTI may assist in identification of preterm infants at risk for language impairment, guiding early intervention.

Diffusion tensor imaging is associated with motor outcomes of very preterm born children at 11 years of age

AIM

Very preterm children born <32 weeks of gestation are at risk for motor difficulties such as cerebral palsy and developmental coordination disorder. This study explores the association between diffusion tensor imaging metrics at term and motor outcomes at 11 years of age.

METHODS

A cohort of 37 very preterm infants (mean gestational age 29 4/7, SD 2 0/7) born in 2004-2006 in Turku University Hospital underwent diffusion tensor imaging at term. A region of interest analysis of fractional anisotropy and mean diffusivity was performed. Motor outcomes at 11 years of age were measured with the Movement Assessment Battery for Children - Second Edition.

RESULTS

The diffusion metrics of the corpus callosum (genu P = .005, splenium P = .049), the left corona radiata (P = .035) and the right optic radiation (P = .017) were related to later motor performance. Mean diffusivity decreased and fractional anisotropy increased in proportion to the improving performance.

CONCLUSION

The diffusion metrics of the genu and splenium of the corpus callosum, the left corona radiata and the right optic radiation at term were associated with motor skills at 11 years of age. Diffusion tensor imaging should be further studied as a potential tool in recognising children at risk for motor impairment.

Nutrition and the developing brain: the road to optimizing early neurodevelopment: a systematic review

BACKGROUND

Neonatal intensive care practices have resulted in marked improvements in the survival of premature infants; however, they remain at significant risk for adverse neurodevelopmental outcomes. The impact of current nutritional practices on brain development following early extra-uterine exposure in premature infants is not well known.

METHODS

We performed a systematic review to investigate nutritional effects on postnatal brain development in healthy term and prematurely born infants utilizing advanced magnetic resonance imaging tools.

RESULTS

Systematic screen yielded 595 studies for appraisal. Of these, 22 total studies were selected for inclusion in the review, with findings summarized in a qualitative, descriptive fashion.

CONCLUSION

Fat and energy intake are associated with improved brain volume and development in premature infants. While breast milk intake and long-chain polyunsaturated fatty acid supplementation has been proven beneficial in term infants, the impact in preterm infants is less well understood.

Neurologic Injury and Brain Growth in the Setting of Long-Gap Esophageal Atresia Perioperative Critical Care: A Pilot Study

We previously showed that infants born with long-gap esophageal atresia (LGEA) demonstrate clinically significant brain MRI findings following repair with the Foker process. The current pilot study sought to identify any pre-existing (PRE-Foker process) signs of brain injury and to characterize brain and corpus callosum (CC) growth. Preterm and full-term infants (n = 3/group) underwent non-sedated brain MRI twice: before (PRE-Foker scan) and after (POST-Foker scan) completion of perioperative care. A neuroradiologist reported on qualitative brain findings. The research team quantified intracranial space, brain, cerebrospinal fluid (CSF), and CC volumes. We report novel qualitative brain findings in preterm and full-term infants born with LGEA before undergoing Foker process. Patients had a unique hospital course, as assessed by secondary clinical end-point measures. Despite increased total body weight and absolute intracranial and brain volumes (cm3) between scans, normalized brain volume was decreased in 5/6 patients, implying delayed brain growth. This was accompanied by both an absolute and relative CSF volume increase. In addition to qualitative findings of CC abnormalities in 3/6 infants, normative CC size (% brain volume) was consistently smaller in all infants, suggesting delayed or abnormal CC maturation. A future larger study group is warranted to determine the impact on the neurodevelopmental outcomes of infants born with LGEA.

Quantitative MRI study of infant regional brain size following surgery for long-gap esophageal atresia requiring prolonged critical care

INTRODUCTION

Little is known regarding the impact of concurrent critical illness and thoracic noncardiac perioperative critical care on postnatal brain development. Previously, we reported smaller total brain volumes in both critically ill full-term and premature patients following complex perioperative critical care for long-gap esophageal atresia (LGEA). Our current report assessed trends in regional brain sizes during infancy, and probed for any group differences.

METHODS

Full-term (n = 13) and preterm (n = 13) patients without any previously known neurological concerns, and control infants (n = 16), underwent non-sedated 3 T MRI in infancy (<1 year old). T2-weighted images underwent semi-automated brain segmentation using Morphologically Adaptive Neonatal Tissue Segmentation (MANTiS). Regional tissue volumes of the forebrain, deep gray matter (DGM), cerebellum, and brainstem are presented as absolute (cm3) and normalized (% total brain volume (%TBV)) values. Group differences were assessed using a general linear model univariate analysis with corrected age at scan as a covariate.

RESULTS

Absolute volumes of regions analyzed increased with advancing age, paralleling total brain size, but were significantly smaller in both full-term and premature patients compared to controls. Normalized volumes (%TBV) of forebrain, DGM, and cerebellum were not different between subject groups analyzed. Normalized brainstem volumes showed group differences that warrant future studies to confirm the same finding.

DISCUSSION

Both full-term and premature critically ill infants undergoing life-saving surgery for LGEA are at risk of smaller total and regional brain sizes. Normalized volumes support globally delayed or diminished brain growth in patients. Future research should look into neurodevelopmental outcomes of infants born with LGEA.

Prediction of Gait Impairment in Toddlers Born Preterm From Near-Term Brain Microstructure Assessed With DTI, Using Exhaustive Feature Selection and Cross-Validation

AIM

To predict gait impairment in toddlers born preterm with very-low-birth-weight (VLBW), from near-term white-matter microstructure assessed with diffusion tensor imaging (DTI), using exhaustive feature selection, and cross-validation.

METHODS

Near-term MRI and DTI of 48 bilateral and corpus callosum regions were assessed in 66 VLBW preterm infants; at 18-22 months adjusted-age, 52/66 participants completed follow-up gait assessment of velocity, step length, step width, single-limb support and the Toddle Temporal-spatial Deviation Index (TDI). Multiple linear models with exhaustive feature selection and leave-one-out cross-validation were employed in this prospective cohort study: linear and logistic regression identified three brain regions most correlated with gait outcome.

RESULTS

Logistic regression of near-term DTI correctly classified infants high-risk for impaired gait velocity (93% sensitivity, 79% specificity), right and left step length (91% and 93% sensitivity, 85% and 76% specificity), single-limb support (100% and 100% sensitivity, 100% and 100% specificity), step width (85% sensitivity, 80% specificity), and Toddle TDI (85% sensitivity, 75% specificity). Linear regression of near-term brain DTI and toddler gait explained 32%-49% variance in gait temporal-spatial parameters. Traditional MRI methods did not predict gait in toddlers.

INTERPRETATION

Near-term brain microstructure assessed with DTI and statistical learning methods predicted gait impairment, explaining substantial variance in toddler gait. Results indicate that at near term age, analysis of a set of brain regions using statistical learning methods may offer more accurate prediction of outcome at toddler age. Infants high risk for single-limb support impairment were most accurately predicted. As a fundamental element of biped gait, single-limb support may be a sensitive marker of gait impairment, influenced by early neural correlates that are evolutionarily and developmentally conserved. For infants born preterm, early prediction of gait impairment can help guide early, more effective intervention to improve quality of life.

WHAT THIS PAPER ADDS

• Accurate prediction of toddler gait from near-term brain microstructure on DTI.• Use of machine learning analysis of neonatal neuroimaging to predict gait.• Early prediction of gait impairment to guide early treatment for children born preterm.

Early Detection of Cerebral Palsy Using Sensorimotor Tract Biomarkers in Very Preterm Infants

BACKGROUND

Our objectives were to evaluate the brain's sensorimotor network microstructure using diffusion magnetic resonance imaging (MRI) at term-corrected age and test the ability of sensorimotor microstructural parameters to accurately predict cerebral palsy in extremely-low-birth-weight infants.

METHODS

We enrolled a prospective pilot cohort of extremely-low-birth-weight preterm infants (birth weight ≤ 1000 g) before neonatal intensive care unit discharge and studied them with structural and diffusion MRI at term-corrected age. Six sensorimotor tracts were segmented, and microstructural parameters from these tracts were evaluated for their ability to predict later development of cerebral palsy, diagnosed at 18 to 22 months corrected age.

RESULTS

We found significant differences in multiple diffusion MRI parameters from five of the six sensorimotor tracts in infants who developed cerebral palsy (n = 5) versus those who did not (n = 36). When compared with structural MRI or individual diffusion MRI biomarkers, the combination of two individual biomarkers-fractional anisotropy of superior thalamic radiations (sensory component) and radial diffusivity of the corticospinal tract-exhibited the highest sensitivity (80%), specificity (97%), and positive likelihood ratio (28.0) for prediction of cerebral palsy. This combination of diffusion MRI biomarkers accurately classified 95% of the study infants.

CONCLUSIONS

Development of cerebral palsy in very preterm infants is preceded by early brain injury or immaturity to one or more sensorimotor tracts. A larger study is warranted to evaluate if a combination of sensorimotor microstructural biomarkers could accurately facilitate early diagnosis of cerebral palsy.

In vivo high-resolution diffusion tensor imaging of the developing neonatal rat cortex and its relationship to glial and dendritic maturation

Diffusion tensor imaging (DTI) is increasingly utilized as a sensitive tool for studying brain maturation and injuries during the neonatal period. In this study, we acquired high resolution in vivo DTI data from neonatal rat brains from postnatal day 2 (P2) to P10 and correlated temporal changes in DTI derived markers with microstructural organization of glia, axons, and dendrites during this critical period of brain development. Group average images showed dramatic temporal changes in brain morphology, fractional anisotropy (FA) and mean diffusivity (MD). Most cortical regions showed a monotonous decline in FA and an initial increase in MD from P2 to P8 that declined slightly by P10. Qualitative histology revealed rapid maturation of the glial and dendritic networks in the developing cortex. In the cingulate and motor cortex, the decreases in FA over time significantly correlated with structural anisotropy values computed from histological sections stained with glial and dendritic markers. However, in the sensory and visual cortex, other factors probably contributed to the observed decreases in FA. We did not observe any significant correlations between FA and structural anisotropy computed from the axonal histological marker.

Structural brain maturation differs between preterm and term piglets, whereas brain activity does not

AIM

The aim of the study was to investigate whether amplitude-integrated electroencephalography (aEEG) and cerebral magnetic resonance imaging (MRI) in preterm piglets would provide measures of cerebral functional, microstructural and anatomical maturation, which might reflect the signs of functional brain immaturity, documented in preterm piglets.

METHODS

During July-October 2013 at the NEOMUNE Centre, Copenhagen University, Denmark, 31 preterm (90% gestation) and 10 term piglets underwent aEEG on days 1, 2, 4 and 11, and MRI on day 25. Physical activity levels were recorded.

RESULTS

Preterm showed delayed neonatal arousal and physical activity, relative to term piglets. Preterm piglets had lower growth rates and brain volume than term piglets, but aEEG patterns were similar. MRI mean diffusivity was also similar, but fractional anisotropy (FA) was lower in preterm piglets (p < 0.001).

CONCLUSION

Functional brain maturation, as assessed by aEEG, was relatively advanced in preterm piglets. Conversely, the low FA in the preterm piglets suggests that the white matter microstructure remains less mature in preterm compared to term piglets at postnatal day 25. The results might be utilised to define whether and how preterm piglets may contribute to preclinical models for brain development in preterm infants.

The Impact of Early Neuroimaging and Developmental Assessment in a Preterm Infant Diagnosed with Cerebral Palsy

Premature infants are at risk for cerebral palsy (CP) that is typically diagnosed between 18-24 months. We present a case study of an infant who was discharged from the neonatal intensive care unit (NICU) without obvious neurological deficits but was later diagnosed with hemiplegic CP. The infant was enrolled in an infant motor study, which included neuroimaging and developmental motor assessments. At term, anatomical MRI showed bilateral periventricular leukomalacia, abnormal brain metabolites in frontal white matter via MR spectroscopy (MRS), and low fractional anisotropy (FA) values obtained from diffusional kurtosis imaging (DKI) in several cortical white matter tracts compared to a group of typically developing infants without neuroimaging abnormalities. In addition, the infant scored below average on a developmental assessment administered at term and three months as well as on the standard Bayley III assessment at 12 months. Abnormal neuroimaging and low scores on the early developmental assessment prompted referral for intervention services at two months. With intensive therapy, by 45 months, the infant was average in self-care, mobility, and communication skills, although below average in visual motor and gross motor coordination. This case highlights the clinical impact of early detection and referral using combined neuroimaging and developmental testing.

Preterm neuroimaging and neurodevelopmental outcome: a focus on intraventricular hemorrhage, post-hemorrhagic hydrocephalus, and associated brain injury

Intraventricular hemorrhage in the setting of prematurity remains the most common cause of acquired hydrocephalus. Neonates with progressive post-hemorrhagic hydrocephalus are at risk for adverse neurodevelopmental outcomes. The goal of this review is to describe the distinct and often overlapping types of brain injury in the preterm neonate, with a focus on neonatal hydrocephalus, and to connect injury on imaging to neurodevelopmental outcome risk. Head ultrasound and magnetic resonance imaging findings are described separately. The current state of the literature is imprecise and we end the review with recommendations for future radiologic and neurodevelopmental research.

Cerebellar peduncle injury predicts motor impairments in preterm infants: A quantitative tractography study at term-equivalent age

PURPOSE

Cerebellar injury is well established as an important finding in preterm infants with cerebral palsy (CP). In this study, we investigated associations between injury to the cerebellar peduncles and motor impairments in preterm infants using quantitative tractography at term-equivalent age, which represents an early phase before the onset of motor impairments.

METHODS

We studied 64 preterm infants who were born at <33 weeks gestational age. These infants were divided into three groups: CP, Non-CP (defined as infants with periventricular leukomalacia but having normal motor function), and a Normal group. Diffusion tensor imaging was performed at term-equivalent age and motor function was assessed no earlier than a corrected age of 2 years. Using tractography, we measured fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of the superior cerebellar peduncles (SCP) and middle cerebellar peduncles (MCP), as well as the motor/sensory tracts.

RESULTS

The infants in the CP group had significantly lower FA of the SCP and sensory tract than those in the other groups. There was no significant difference in FA and ADC of the motor tract among the three groups. Severity of CP had a significant correlation with FA of the MCP, but not with the FA of other white matter tracts.

CONCLUSION

Our results suggested that the infants with CP had injuries of the ascending tracts (e.g. the SCP and sensory tract), and that additional MCP injury might increase the severity of CP. Quantitative tractography assessment at term-equivalent age may be useful for screening preterm infants for prediction of future motor impairments.

Mild cerebellar injury does not significantly affect cerebral white matter microstructural organization and neurodevelopmental outcome in a contemporary cohort of preterm infants

BackgroundPreterm birth is associated with an increased risk of cerebellar injury. The aim of this study was to assess the impact of cerebellar hemorrhages (CBH) on cerebral white matter microstructural tissue organization and cerebellar volume at term-equivalent age (TEA) in extremely preterm infants. Furthermore, we aimed to evaluate the association between CBH and neurodevelopmental outcome in late infancy.MethodsA total of 24 preterm infants with punctate CBH were included and each matched to two preterm control infants. T1-, T2-weighted images and diffusion-weighted imaging were acquired on a 3T magnetic resonance imaging (MRI) system. Regions of interest were drawn on a population-specific neonatal template and automatically registered to individual fractional anisotropy (FA) maps. Brain volumes were automatically computed. Neurodevelopmental outcome was assessed using the Bayley scales of Infant and Toddler Development at 2 years of corrected age.ResultsCBHs were not significantly related to FA in the posterior limb of the internal capsule and corpus callosum or to cerebellar volume. Infants with CBH did not have poorer neurodevelopmental outcome compared with control infants.ConclusionThese findings suggest that the impact of mild CBH on early macroscale brain development may be limited. Future studies are needed to assess the effects of CBH on long-term neurodevelopment.

Baby brain atlases

The baby brain is constantly changing due to its active neurodevelopment, and research into the baby brain is one of the frontiers in neuroscience. To help guide neuroscientists and clinicians in their investigation of this frontier, maps of the baby brain, which contain a priori knowledge about neurodevelopment and anatomy, are essential. "Brain atlas" in this review refers to a 3D-brain image with a set of reference labels, such as a parcellation map, as the anatomical reference that guides the mapping of the brain. Recent advancements in scanners, sequences, and motion control methodologies enable the creation of various types of high-resolution baby brain atlases. What is becoming clear is that one atlas is not sufficient to characterize the existing knowledge about the anatomical variations, disease-related anatomical alterations, and the variations in time-dependent changes. In this review, the types and roles of the human baby brain MRI atlases that are currently available are described and discussed, and future directions in the field of developmental neuroscience and its clinical applications are proposed. The potential use of disease-based atlases to characterize clinically relevant information, such as clinical labels, in addition to conventional anatomical labels, is also discussed.

Characteristic phase distribution in the white matter of infants on phase difference enhanced imaging

BACKGROUND AND PURPOSE

The infantile brain is continuously undergoing development. Non-invasive methods to assess the neurological development of infants are important for the early detection of abnormalities. Some microstructures in the brain have been demonstrated via phase difference-enhanced imaging (PADRE), which may reflect myelin-related microstructures. We aimed to assess the white matter (WM) signal distribution in infants using PADRE and compared it with that using T1-weighted images (T1WI) and diffusion tensor imaging (DTI) on magnetic resonance imaging (MRI).

MATERIALS AND METHOD

This study included 18 infants (postmenstrual age at MRI, 37-40 weeks) without abnormal findings on MRI. Signal distribution using T1WI, a fractional anisotropy (FA) map and PADRE was assessed regarding the following intraparenchymal structures: the optic radiation (OR), internal capsule (IC), corpus callosum, corticospinal tract (CST), semiovale center and subcortical regions.

RESULTS

We found that the signal distribution was significantly different (P<0.001) with a relatively large signal change found at the IC and CST across the three imaging methods. Signal changes were also greater at the OR and rolandic subcortical WM on PADRE, whereas these were smaller on T1WI and FA.

CONCLUSION

PADRE demonstrated a characteristic phase shift distribution in infantile WM, which was different from that observed on T1WI and FA maps, and may demonstrate the developing myelin-related structures. PADRE can be a unique indicator of infantile brain development.

Neurodevelopmental outcome in very preterm and very-low-birthweight infants born over the past decade: a meta-analytic review

AIM

The purpose of this systematic review was to provide an up-to-date global overview of the separate prevalences of motor and cognitive delays and cerebral palsy (CP) in very preterm (VPT) and very-low-birthweight (VLBW) infants.

METHOD

A comprehensive search was conducted across four databases. Cohort studies reporting the prevalence of CP and motor or cognitive outcome from 18 months corrected age until 6 years of VPT or VLBW infants born after 2006 were included. Pooled prevalences were calculated with random-effects models.

RESULTS

Thirty studies were retained, which included a total of 10 293 infants. The pooled prevalence of cognitive and motor delays, evaluated with developmental tests, was estimated at 16.9% (95% confidence interval [CI] 10.4-26.3) and 20.6% (95% CI 13.9-29.4%) respectively. Mild delays were more frequent than moderate-to-severe delays. Pooled prevalence of CP was estimated to be 6.8% (95% CI 5.5-8.4). Decreasing gestational age and birthweight resulted in higher prevalences. Lower pooled prevalences were found with the Third Edition of the Bayley Scales of Infant Development than with the Second Edition.

INTERPRETATION

Even though neonatal intensive care has improved over recent decades, there is still a wide range of neurodevelopmental disabilities resulting from VPT and VLBW births. However, pooled prevalences of CP have diminished over the years.

WHAT THIS PAPER ADDS

The Bayley Scales of Infant and Toddler Development, Third Edition reported lower pooled prevalences of motor and cognitive delays than the Second Edition. The pooled prevalence of cerebral palsy in infants born extremely preterm was reduced compared with previous meta-analyses.

Temporal-spatial reach parameters derived from inertial sensors correlate to neurodevelopment in toddlers born preterm

Temporal-spatial reach parameters are revealing of upper-limb function in children with motor impairments, but have not been quantified in a toddler population. This work quantitatively characterizes temporal-spatial reach in typically-developing (TD) and very-low-birth-weight (VLBW) preterm toddlers, who are at increased risk of motor impairment. 47 children born VLBW (<1500 g birth-weight; ≤32 weeks gestation) and 22 TD children completed a reaching assessment at 18-22 months of age, adjusted for prematurity. Inertial sensors containing accelerometers, gyroscopes and magnetometers were fixed to toddlers' wrists while they reached for a cube. Reach time, path length, velocity at contact, peak velocity magnitude and timing, acceleration at contact, and peak acceleration were derived from inertial-sensor and high-speed video data. Preterm children also received the Bayley Scales of Infant Development-3rd Edition (BSID-III). Compared to TD toddlers, preterm toddlers had significantly different reach path length, velocity at contact, peak velocity magnitude and timing, acceleration at contact, and peak acceleration. Among preterm toddlers, decreased reach time (rho = -.346, p = .018), decreased time to peak velocity (r = -.390, p = .007), and increased peak acceleration (r = .298, p = .044) correlated to higher BSID-III fine motor scores. Toddlers with below-average fine motor scores had significantly higher peak and contact velocity. Preterm toddlers demonstrated substantial differences in temporal-spatial reach parameters compared to TD toddlers, and evidence indicated several reach parameters were revealing of function and may be useful as a clinical assessment.

Gestational age, not transient hyperthyrotropinemia impacts brain white matter diffusion tensor imaging in premature infants

Transient hypothyroidism is common in premature infants and increases the risk of adverse neurodevelopmental outcomes. Thyroid hormone (TH) is involved in oligodendrocyte development and myelination, however, whether transient hypothyroidism is associated with oligodendrocyte dysplasia and abnormal myelination is unclear. The aim of the present study was to investigate correlations among TH levels, neurodevelopmental outcomes and white matter (WM) microstructure in premature infants. The authors designed a cohort study recruiting 81 premature infants (age, 23-35 weeks). A total of 17 were born with a gestational age (GA) <30 weeks (early preterm group) and 64 of them were born with a GA ≥30 weeks (late preterm group). For outcome measurement, thyroid stimulating hormone (TSH) levels at 0, 18, and 24 h of admission were measured. Neurodevelopmental outcomes were assessed using Bayley III test. Diffusion tensor imaging was used to explore the characterization of WM microstructure. The data demonstrated that GA, however not TSH level was associated with neurodevelopmental outcomes in the following 2 years. Fractional anisotrophy (FA) increased with TSH0 levels over anterior limb of internal capsule, while axial diffusivity decreased with TSH0 levels over splenium of corpus callosum (CC). The late preterm group had more intact WM integrity over the internal and external capsule (EC) in FA compared with the early preterm group. Infants with motor dysfunction had significantly increased mean diffusivity (MD) values at regions of interest in the genu and splenium of CC. The results of the present study demonstrated that GA, however not transient hypothyroidism influenced neurodevelopmental outcomes in the premature infants. FA increased with age in a regionally-specific manner over regions of the internal capsule and EC. MD may act as a potential predictor for motor function in premature babies.

Prediction of cognitive and motor development in preterm children using exhaustive feature selection and cross-validation of near-term white matter microstructure

BACKGROUND

Advanced neuroimaging and computational methods offer opportunities for more accurate prognosis. We hypothesized that near-term regional white matter (WM) microstructure, assessed on diffusion tensor imaging (DTI), using exhaustive feature selection with cross-validation would predict neurodevelopment in preterm children.

METHODS

Near-term MRI and DTI obtained at 36.6 ± 1.8 weeks postmenstrual age in 66 very-low-birth-weight preterm neonates were assessed. 60/66 had follow-up neurodevelopmental evaluation with Bayley Scales of Infant-Toddler Development, 3rd-edition (BSID-III) at 18-22 months. Linear models with exhaustive feature selection and leave-one-out cross-validation computed based on DTI identified sets of three brain regions most predictive of cognitive and motor function; logistic regression models were computed to classify high-risk infants scoring one standard deviation below mean.

RESULTS

Cognitive impairment was predicted (100% sensitivity, 100% specificity; AUC = 1) by near-term right middle-temporal gyrus MD, right cingulate-cingulum MD, left caudate MD. Motor impairment was predicted (90% sensitivity, 86% specificity; AUC = 0.912) by left precuneus FA, right superior occipital gyrus MD, right hippocampus FA. Cognitive score variance was explained (29.6%, cross-validated Rˆ2 = 0.296) by left posterior-limb-of-internal-capsule MD, Genu RD, right fusiform gyrus AD. Motor score variance was explained (31.7%, cross-validated Rˆ2 = 0.317) by left posterior-limb-of-internal-capsule MD, right parahippocampal gyrus AD, right middle-temporal gyrus AD.

CONCLUSION

Search in large DTI feature space more accurately identified neonatal neuroimaging correlates of neurodevelopment.

Clinical neuroimaging in the preterm infant: Diagnosis and prognosis

Perinatal care advances emerging over the past twenty years have helped to diminish the mortality and severe neurological morbidity of extremely and very preterm neonates (e.g., cystic Periventricular Leukomalacia [c-PVL] and Germinal Matrix Hemorrhage - Intraventricular Hemorrhage [GMH-IVH grade 3-4/4]; 22 to < 32 weeks of gestational age, GA). However, motor and/or cognitive disabilities associated with mild-to-moderate white and gray matter injury are frequently present in this population (e.g., non-cystic Periventricular Leukomalacia [non-cystic PVL], neuronal-axonal injury and GMH-IVH grade 1-2/4). Brain research studies using magnetic resonance imaging (MRI) report that 50% to 80% of extremely and very preterm neonates have diffuse white matter abnormalities (WMA) which correspond to only the minimum grade of severity. Nevertheless, mild-to-moderate diffuse WMA has also been associated with significant affectations of motor and cognitive activities. Due to increased neonatal survival and the intrinsic characteristics of diffuse WMA, there is a growing need to study the brain of the premature infant using non-invasive neuroimaging techniques sensitive to microscopic and/or diffuse lesions. This emerging need has led the scientific community to try to bridge the gap between concepts or ideas from different methodologies and approaches; for instance, neuropathology, neuroimaging and clinical findings. This is evident from the combination of intense pre-clinical and clinicopathologic research along with neonatal neurology and quantitative neuroimaging research. In the following review, we explore literature relating the most frequently observed neuropathological patterns with the recent neuroimaging findings in preterm newborns and infants with perinatal brain injury. Specifically, we focus our discussions on the use of neuroimaging to aid diagnosis, measure morphometric brain damage, and track long-term neurodevelopmental outcomes.

Functional variation of SHP-2 promoter is associated with preterm birth and delayed myelination and motor development in preterm infants

Src homology 2 domain-containing protein tyrosine phosphatase 2 (SHP-2) is a cytoplasmic tyrosine phosphatase that is highly expressed in hematopoietic cells and in the CNS and exerts opposite effects on signal transduction by exerting a neuroprotective or proapoptotic effect. Several mutations of SHP-2 have been found in children with myeloproliferative disorders or malignant leukemia, and some of these can affect brain development. In the present study, we aimed to identify and functionally characterize genetic variations in SHP-2 in 72 preterm and 58 full-term infants and to evaluate the effect of the variations on neurodevelopment in preterm infants. Twelve genetic variations were identified. Among them, two variations in the SHP-2 promoter, g.-317C > T and g.-273G > A, were found to significantly increase promoter activity, and the frequency of g.-273G > A was higher in preterm infants than in full-term infants. Two transcription factors, NF-κB and GABPα, were found to be involved in the transcriptional regulation of SHP-2 by the two above-mentioned variations. In particular, we found that g.-273G > A was significantly associated with delayed myelination and poor motor development in preterm infants. Our results suggest that a functional promoter variation in SHP-2 is associated with spontaneous preterm birth itself as well as white matter myelination and neurodevelopment.

Neonatal Hyperoxia Perturbs Neuronal Development in the Cerebellum

Impaired postnatal brain development of preterm infants often results in neurological deficits. Besides pathologies of the forebrain, maldeveolopment of the cerebellum is increasingly recognized to contribute to psychomotor impairments of many former preterm infants. However, causes are poorly defined. We used a hyperoxia model to define neonatal damage in cerebellar granule cell precursors (GCPs) and in Purkinje cells (PCs) known to be essential for interaction with GCPs during development. We exposed newborn rats to 24 h 80% O₂ from age P6 to P7 to identify postnatal and long-term damage in cerebellar GCPs at age P7 after hyperoxia and also after recovery in room air thereafter until P11 and P30. We determined proliferation and apoptosis of GCPs and immature neurons by immunohistochemistry, quantified neuronal damage by qPCR and Western blots for neuronal markers, and measured dendrite outgrowth of PCs by CALB1 immunostainings and by Sholl analysis of Golgi stainings. After hyperoxia, proliferation of PAX6+ GCPs was decreased at P7, while DCX + CASP3+ cells were increased at P11. Neuronal markers Pax6, Tbr2, and Prox1 were downregulated at P11 and P30. Neuronal damage was confirmed by reduced NeuN protein expression at P30. Sonic hedgehog (SHH) was significantly decreased at P7 and P11 after hyperoxia and coincided with lower CyclinD2 and Hes1 expression at P7. The granule cell injury was accompanied by hampered PC maturation with delayed dendrite formation and impaired branching. Neonatal injury induced by hyperoxia inhibits PC functioning and impairs granule cell development. As a conclusion, maldevelopment of the cerebellar neurons found in preterm infants could be caused by postnatal oxygen toxicity.

Neurologic Correlates of Gait Abnormalities in Cerebral Palsy: Implications for Treatment

Cerebral palsy (CP) is the most common movement disorder in children. A diagnosis of CP is often made based on abnormal muscle tone or posture, a delay in reaching motor milestones, or the presence of gait abnormalities in young children. Neuroimaging of high-risk neonates and of children diagnosed with CP have identified patterns of neurologic injury associated with CP, however, the neural underpinnings of common gait abnormalities remain largely uncharacterized. Here, we review the nature of the brain injury in CP, as well as the neuromuscular deficits and subsequent gait abnormalities common among children with CP. We first discuss brain injury in terms of mechanism, pattern, and time of injury during the prenatal, perinatal, or postnatal period in preterm and term-born children. Second, we outline neuromuscular deficits of CP with a focus on spastic CP, characterized by muscle weakness, shortened muscle-tendon unit, spasticity, and impaired selective motor control, on both a microscopic and functional level. Third, we examine the influence of neuromuscular deficits on gait abnormalities in CP, while considering emerging information on neural correlates of gait abnormalities and the implications for strategic treatment. This review of the neural basis of gait abnormalities in CP discusses what is known about links between the location and extent of brain injury and the type and severity of CP, in relation to the associated neuromuscular deficits, and subsequent gait abnormalities. Targeted treatment opportunities are identified that may improve functional outcomes for children with CP. By providing this context on the neural basis of gait abnormalities in CP, we hope to highlight areas of further research that can reduce the long-term, debilitating effects of CP.

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.

Correlating early motor skills to white matter abnormalities in preterm infants using diffusion tensor imaging

PURPOSE

Diffusion tensor imaging (DTI) can detect injury to specific white matter (WM) tracts involved with sensorimotor processing and may provide sensitive measures for latent or nascent motor skills. We hypothesized that DTI measures of WM fractional anisotropy (FA) could predict early motor scores on a standardized assessment in a cohort of preterm infants at risk for WM injury.

METHODS

In this prospective study, preterm infants (n= 26, 11 female, 15 male, mean gestational age 29.1 ± 2.5) underwent the Test of Infant Motor Performance (TIMP) at term and at 12 weeks corrected age (CA) and underwent an non-sedated magnetic resonance imaging (MRI) with DTI at a mean of 42 ± 1.5 weeks CA. Fractional anisotropy (FA) was measured by Voxelwise statistical analysis using Tract-Based Spatial Statistics (TBSS) in the specific regions of interest.

RESULTS

Significant differences were found between infants with poor versus average performance on motor assessments at 12-weeks and FA values in several left hemispheric WM tracts (p< 0.05). High FA of the left anterior limb of the internal capsule (ALIC) predicted mean increase in TIMP scores on specific items for head lift in prone and head lift turn to sound (p= 0.045 and p= 0.002).

CONCLUSION

Subtle WM injury, as indicated by low FA in left WM tracts, can predict outcomes of early motor skills performance testing at 3 months. Early DTI may identify infants with silent WM injury who need early intervention. Further studies may establish if individual tract FA improve after targeted treatment.