Disrupted cerebellar development in preterm infants is associated with impaired neurodevelopmental outcome

Cerebellar haemorrhage and atrophy in infants born extremely preterm with intraventricular haemorrhage

AIM

To investigate the impact of cerebellar haemorrhage (CBH) and atrophy in infants born extremely preterm with intraventricular haemorrhage (IVH) on neurodevelopment at 2 years of age.

METHOD

This retrospective case-control study included infants born at less than 28 weeks' gestation with IVH over a 10-year period. CBH, along with the assessment of cerebellar size, using magnetic resonance imaging, were studied. The impact of injuries on neurodevelopmental outcome at 2 years' corrected age was conducted, using multivariable regression analysis for comprehensive evaluation.

RESULTS

In a cohort of 103 patients, 69 (67.0%) showed CBH with a median grade of 1 (interquartile range = 0-3). At the corrected age of 2 years, CBH was significantly associated with impaired cognitive and motor outcome. CBH emerged as an independent predictor of poor cognitive and motor development, as well as cerebral palsy. Cerebellar atrophy, affecting 30 (29.1%) infants, was linked to a significantly worse outcome across all domains. Conversely, an increase in cerebellar size was correlated with improved motor development.

INTERPRETATION

Infants born extremely preterm with IVH and concomitant CBH exhibited significant cognitive and motor impairment. The severity of developmental delay correlated with the grade of CBH. These findings hold potential to support the prediction of long-term outcome and parental counselling.

Cerebellar hemorrhage in neonates: pattern analysis by ultrasonography and magnetic resonance imaging

BACKGROUND

Cerebellar hemorrhage in neonates is increasingly being identified but is still underdiagnosed. While magnetic resonance imaging (MRI) is the optimal imaging modality for cerebellar hemorrhage evaluation, ultrasonography (US) is commonly used for screening. Characterizing the patterns and distribution of cerebellar hemorrhage lesions can help facilitate its detection by aiding to focus on prevailing type of cerebellar hemorrhage.

OBJECTIVE

This study aimed to analyze the patterns of cerebellar hemorrhage in neonates, comparing US findings with MRI.

MATERIALS AND METHODS

This was a retrospective study of 765 neonatal intensive care unit (NICU)-admitted neonates who underwent brain MRI due to various clinical and radiological requirements. Two pediatric radiologists reviewed brain MRI and US in consensus, and cerebellar hemorrhage patterns were classified based on MRI findings: type 1, punctate cerebellar hemorrhage without cerebellar volume loss; type 2, focal cerebellar hemorrhage with cerebellar volume loss; type 3, ovoid/crescent cerebellar hemorrhage in the periphery of the cerebellar hemisphere; type 4, isolated vermian cerebellar hemorrhage; type 5, cerebellar hemorrhage involving almost the entire cerebellar hemisphere. The distribution and US detection rates of cerebellar hemorrhage were compared according to the cerebellar hemorrhage type.

RESULTS

A total of 56 (33 male, 23 female) cases (7.32%) among 765 MRIs showed cerebellar hemorrhage (median gestational age, 27 + 1 weeks [IQR 5 + 2]; median birth weight, 955 g [IQR 882.5]). The most common pattern was type 1 (60.7%). Type 3 cerebellar hemorrhage was more commonly observed in the inferior and peripheral cerebellum compared to types 1 and 2 cerebellar hemorrhage (P=0.002). In retrospective review of images, type 3 was the most commonly missed type of cerebellar hemorrhage (initial US detection rate, 33.3%; retrospective US detection rate, 75%).

CONCLUSION

This study underscores the importance of understanding cerebellar hemorrhage patterns and suggests that careful inspection of inferior and periphery of the cerebellum is important to avoid missed diagnosis of cerebellar hemorrhage.

A Simple MRI Score Predicts Pathological General Movements in Very Preterm Infants with Brain Injury-Retrospective Cohort Study

BACKGROUND/OBJECTIVES

Very preterm infants are at increased risk of brain injury and impaired brain development. The Total Abnormality Score and biometric parameters, such as biparietal width, interhemispheric distance and transcerebellar diameter, are simple measures to evaluate brain injury, development and growth using cerebral magnetic resonance imaging data at term-equivalent age. The aim of this study was to evaluate the association between the Total Abnormality Score and biometric parameters with general movements in very preterm infants with brain injury.

METHODS

This single-center retrospective cohort study included 70 very preterm infants (≤32 weeks' gestation and/or <1500 g birth weight) born between January 2017 and June 2021 in a level-three neonatal intensive care unit with brain injury-identified using cerebral magnetic resonance imaging data at term-equivalent age. General movements analysis was carried out at corrected age of 8-16 weeks. Binary logistic regression and Spearman correlation were used to examine the associations between the Total Abnormality Score and biometric parameters with general movements.

RESULTS

There was a significant association between the Total Abnormality Score and the absence of fidgety movements [OR: 1.19, 95% CI = 1.38-1.03] as well as a significant association between the transcerebellar diameter and fidgety movements (Spearman ρ = -0.269, p < 0.05).

CONCLUSIONS

Among very preterm infants with brain injury, the Total Abnormality Score can be used to predict the absence of fidgety movements and may be an easily accessible tool for identifying high-risk very preterm infants and planning early interventions accordingly.

Fibrinogen inhibits sonic hedgehog signaling and impairs neonatal cerebellar development after blood-brain barrier disruption

Cerebellar injury in preterm infants with central nervous system (CNS) hemorrhage results in lasting neurological deficits and an increased risk of autism. The impact of blood-induced pathways on cerebellar development remains largely unknown, so no specific treatments have been developed to counteract the harmful effects of blood after neurovascular damage in preterm infants. Here, we show that fibrinogen, a blood-clotting protein, plays a central role in impairing neonatal cerebellar development. Longitudinal MRI of preterm infants revealed that cerebellar bleeds were the most critical factor associated with poor cerebellar growth. Using inflammatory and hemorrhagic mouse models of neonatal cerebellar injury, we found that fibrinogen increased innate immune activation and impeded neurogenesis in the developing cerebellum. Fibrinogen inhibited sonic hedgehog (SHH) signaling, the main mitogenic pathway in cerebellar granule neuron progenitors (CGNPs), and was sufficient to disrupt cerebellar growth. Genetic fibrinogen depletion attenuated neuroinflammation, promoted CGNP proliferation, and preserved normal cerebellar development after neurovascular damage. Our findings suggest that fibrinogen alters the balance of SHH signaling in the neurovascular niche and may serve as a therapeutic target to mitigate developmental brain injury after CNS hemorrhage.

Cerebellar injury in preterm infants less than 28 weeks gestational age

BACKGROUND

Cerebellar injury is one of the perinatal complications in preterm infants. Recent studies have highlighted the effect of perinatal complications on neurological morbidity. We investigated the perinatal risk factors and morbidity for cerebellar injury in extremely premature infants.

METHODS

This retrospective cohort study included 285 infants born between April 2009 and December 2020 at gestational age <28 weeks at our institution. The infants were divided into two groups based on magnetic resonance imaging findings: those with and without cerebellar injury. We performed a statistical analysis of the perinatal background and short-term morbidity of the two groups.

RESULTS

Significant differences (p < 0.05) were observed between the groups with respect to the perinatal background, especially gestational weeks, birthweight, and hemoglobin values at birth. In the short-term morbidity, significant differences (p < 0.05) were observed in the incidence of respiratory distress syndrome, chronic lung disease, hydrocephalus, severe intraventricular hemorrhage (IVH), and cerebellar hemorrhage. Extensive cerebellar lesions, such as cerebellar agenesis or global cerebellar hypoplasia, accounted for 11 of the 22 cases of cerebellar injury; seven of the 11 cases had severe IVH in addition to cerebellar hemorrhage.

CONCLUSIONS

Gestational age was significantly lower in the cerebellar injury group. The combination of severe IVH and cerebellar hemorrhage may promote cerebellar injury.

Prevalence, Clinical Features, Neuroimaging, and Genetic Findings in Children With Ataxic Cerebral Palsy in Europe

BACKGROUND AND OBJECTIVES

To report on prevalence, associated impairments, severity, and neuroimaging findings in children with ataxic cerebral palsy (CP).

METHODS

In children coded as having ataxic CP in the Central database of Joint Research Center-Surveillance of Cerebral Palsy in Europe (JRC-SCPE) and born during 1980-2010, birth characteristics, severity profiles including associated impairments, neuroimaging patterns, and the presence of syndromes were analyzed. Definitions were according to validated SCPE guidelines. Prevalence over time was estimated using Poisson regression.

RESULTS

In total, 679 children with ataxic CP were identified in 20 European CP registers. The proportion with ataxic CP was 3.8% and varied from 0% to 12.9%. Prevalence over time showed no significant trend. Approximately 70% of children with ataxic CP were able to walk, and 40% had severe intellectual impairment and a high impairment index. Children with ataxic CP were mostly born at term (79%) and with normal birth weight (77%). Neuroimaging patterns revealed normal findings in 29%, brain maldevelopments in 28.5%, miscellaneous findings in 23.5%, and brain injuries in 19%, according to the SCPE classification. Genetic syndromes were described in 9%.

DISCUSSION

This register-based multicenter study on children with ataxic CP provides a large sample size for the analysis of prevalence, severity, and origin of this rare CP subtype. Even with strict inclusion and classification criteria, there is variation between registers on how to deal with this subtype, and diagnosis of ataxic CP remains a challenge. Ataxic cerebral palsy differs from other CP subtypes: children with ataxic CP have a disability profile that is more pronounced in terms of cognitive than gross motor dysfunction. They are mostly term born and the origin rarely suggests acquired injuries. In addition to neuroimaging, a comprehensive genetic workup is particularly recommended for children with this CP type.

Differentiating Genetic Forms of Pontocerebellar Hypoplasia From Acquired Lesions Resembling Pontocerebellar Hypoplasia: Clinical, Neurodevelopmental, and Imaging Insight From 19 Extremely Premature Patients

It is well established that extreme prematurity can be associated with cerebellar lesions potentially affecting the neurologic prognosis. One of the commonly observed lesions in these cases is pontocerebellar hypoplasia resulting from prematurity, which can pose challenges in distinguishing it from genetically caused pontocerebellar hypoplasia. This confusion leads to unacceptable and prolonged diagnostic ambiguity for families as well as difficulties in genetic counseling. Therefore, it is crucial to identify the clinical and neuroradiologic features allowing to differentiate between acquired and genetic forms of pontocerebellar hypoplasia in order to guide clinical practices and improve patient care. In this regard, we report in the present manuscript the clinical, developmental, and radiologic characteristics of 19 very premature children (gestational age <28 weeks, now aged 3-14 years) with cerebellar lesions and discuss the causal mechanisms. Our findings support the notion that a combination of specific clinical and radiologic criteria is essential in distinguishing between acquired and genetic forms of pontocerebellar hypoplasia.

The Association of Dexamethasone and Hydrocortisone with Cerebellar Growth in Premature Infants

OBJECTIVES

Corticosteroids are used to prevent or treat lung disease of prematurity. While neurological side effects have been reported, detailed effects on cerebellar growth are unknown. This study aimed to compare cerebellar growth in premature infants who received dexamethasone or hydrocortisone to premature infants who did not receive postnatal corticosteroids.

STUDY DESIGN

Retrospective case-control study in infants born at a gestational age of <29 weeks and admitted to two level 3 neonatal intensive care units. Exclusion criteria were severe congenital anomalies and cerebellar or severe supratentorial lesions. Infants were treated with dexamethasone (unit 1) or hydrocortisone (unit 2) for chronic lung disease. Controls (unit 1) did not receive postnatal corticosteroids. Sequential head circumference (HC) and ultrasound measurements of transcerebellar diameter (TCD), biparietal diameter (BPD), and corpus callosum-fastigium length (CCFL) were performed until 40 weeks' postmenstrual age (PMA). Growth was assessed using linear mixed models correcting for PMA at measurement, sex, HC z-score at birth, and a propensity score indicating illness severity. Group differences before treatment were assessed using linear regression.

RESULTS

346 infants were included (68 dexamethasone, 37 hydrocortisone, 241 controls). Before starting corticosteroids, TCD, BPD, and HC measurements did not differ between patients and controls at a comparable PMA. After starting treatment, both types of corticosteroid had a negative association with TCD growth. BPD, CCFL, and HC growth were not negatively affected.

CONCLUSION

Administration of dexamethasone and hydrocortisone are both associated with impaired cerebellar growth in premature infants without evident negative associations with cerebral growth.

Longitudinal neonatal brain development and socio-demographic correlates of infant outcomes following preterm birth

Preterm birth results in premature exposure of the brain to the extrauterine environment during a critical period of neurodevelopment. Consequently, infants born preterm are at a heightened risk of adverse behavioural outcomes in later life. We characterise longitudinal development of neonatal regional brain volume and functional connectivity in the first weeks following preterm birth, sociodemographic factors, and their respective relationships to psychomotor outcomes and psychopathology in toddlerhood. We study 121 infants born preterm who underwent magnetic resonance imaging shortly after birth, at term-equivalent age, or both. Longitudinal regional brain volume and functional connectivity were modelled as a function of psychopathology and psychomotor outcomes at 18 months. Better psychomotor functioning in toddlerhood was associated with greater relative right cerebellar volume and a more rapid decrease over time of sensorimotor degree centrality in the neonatal period. In contrast, increased 18-month psychopathology was associated with a more rapid decrease in relative regional subcortical volume. Furthermore, while socio-economic deprivation was related to both psychopathology and psychomotor outcomes, cognitively stimulating parenting predicted psychopathology only. Our study highlights the importance of longitudinal imaging to better predict toddler outcomes following preterm birth, as well as disparate environmental influences on separable facets of behavioural development in this population.

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

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

Early development of sleep and brain functional connectivity in term-born and preterm infants

The proper development of sleep and sleep-wake rhythms during early neonatal life is crucial to lifelong neurological well-being. Recent data suggests that infants who have poor quality sleep demonstrate a risk for impaired neurocognitive outcomes. Sleep ontogenesis is a complex process, whereby alternations between rudimentary brain states-active vs. wake and active sleep vs. quiet sleep-mature during the last trimester of pregnancy. If the infant is born preterm, much of this process occurs in the neonatal intensive care unit, where environmental conditions might interfere with sleep. Functional brain connectivity (FC), which reflects the brain's ability to process and integrate information, may become impaired, with ensuing risks of compromised neurodevelopment. However, the specific mechanisms linking sleep ontogenesis to the emergence of FC are poorly understood and have received little investigation, mainly due to the challenges of studying causal links between developmental phenomena and assessing FC in newborn infants. Recent advancements in infant neuromonitoring and neuroimaging strategies will allow for the design of interventions to improve infant sleep quality and quantity. This review discusses how sleep and FC develop in early life, the dynamic relationship between sleep, preterm birth, and FC, and the challenges associated with understanding these processes. IMPACT: Sleep in early life is essential for proper functional brain development, which is essential for the brain to integrate and process information. This process may be impaired in infants born preterm. The connection between preterm birth, early development of brain functional connectivity, and sleep is poorly understood. This review discusses how sleep and brain functional connectivity develop in early life, how these processes might become impaired, and the challenges associated with understanding these processes. Potential solutions to these challenges are presented to provide direction for future research.

Cerebellar injury in premature neonates: Imaging findings and relationship with outcome

Cerebellar hemorrhagic injury (CHI) is a common complication of preterm birth. There are now many studies that have investigated the developmental consequences of CHI. This review summarizes the present state of evidence regarding the outcomes of prematurity related CHI, with a particular focus on the neuroimaging characteristics associated with adverse outcomes. Studies published to date suggest that the severity of functional deficits is dependent on injury size and topography. However, the unique contribution of the CHI to outcomes still needs to be further investigated to ensure optimal prognostic counseling.

A novel RIP1/RIP3 dual inhibitor promoted OPC survival and myelination in a rat neonatal white matter injury model with hOPC graft

Background

The dual inhibitors of receptor interacting protein kinase-1 and -3 (RIP1 and RIP3) play an important role in cell death processes and inflammatory responses. White matter injury (WMI), a leading cause of neurodevelopmental disabilities in preterm infants, which is characterized by extensive myelination disturbances and demyelination. Neuroinflammation, leads to the loss and differentiation-inhibition of oligodendrocyte precursor cells (OPCs), represents a major barrier to myelin repair. Whether the novel RIP1/RIP3 dual inhibitor ZJU-37 can promote transplanted OPCs derived from human neural stem cells (hOPCs) survival, differentiation and myelination remains unclear. In this study, we investigated the effect of ZJU-37 on myelination and neurobehavioral function in a neonatal rat WMI model induced by hypoxia and ischemia.

Methods

In vivo, P3 rat pups were subjected to right common carotid artery ligation and hypoxia, and then treated with ZJU-37 or/and hOPCs, then OPCs apoptosis, myelination, glial cell and NLRP3 inflammasome activation together with cognitive outcome were evaluated at 12 weeks after transplantation. In vitro, the effect of ZJU-37 on NLRP3 inflammasome activation in astrocytes induced by oxygen–glucose deprivation (OGD) were examined by western blot and immunofluorescence. The effect of ZJU-37 on OPCs apoptosis induced by the conditioned medium from OGD-injured astrocytes (OGD-astrocyte-CM) was analyzed by flow cytometry and immunofluorescence.

Results

ZJU-37 combined with hOPCs more effectively decreased OPC apoptosis, promoted myelination in the corpus callosum and improved behavioral function compared to ZJU-37 or hOPCs treatment. In addition, the activation of glial cells and NLRP3 inflammasome was reduced by ZJU-37 or/and hOPCs treatment in the neonatal rat WMI model. In vitro, it was also confirmed that ZJU-37 can suppress NLRP3 inflammasome activation in astrocytes induced by OGD. Not only that, the OGD-astrocyte-CM treated with ZJU-37 obviously attenuated OPC apoptosis and dysdifferentiation caused by the OGD-astrocyte-CM.

Conclusions

The novel RIP1/RIP3 dual inhibitor ZJU-37 may promote OPC survival, differentiation and myelination by inhibiting NLRP3 inflammasome activation in a neonatal rat model of WMI with hOPC graft.

Cerebellum and Prematurity: A Complex Interplay Between Disruptive and Dysmaturational Events

The cerebellum plays a critical regulatory role in motor coordination, cognition, behavior, language, memory, and learning, hence overseeing a multiplicity of functions. Cerebellar development begins during early embryonic development, lasting until the first postnatal years. Particularly, the greatest increase of its volume occurs during the third trimester of pregnancy, which represents a critical period for cerebellar maturation. Preterm birth and all the related prenatal and perinatal contingencies may determine both dysmaturative and lesional events, potentially involving the developing cerebellum, and contributing to the constellation of the neuropsychiatric outcomes with several implications in setting-up clinical follow-up and early intervention.

Pontocerebellar hypoplasia type 11: Does the genetic defect determine timing of cerebellar pathology?

Pontocerebellar hypoplasia (PCH) comprises a clinically and genetically heterogeneous group of disorders characterized by hypoplasia and degeneration of the cerebellum and ventral pons. To date at least 18 different clinical subtypes of PCH associated with pathogenic variants in 19 different genes have been described. Only recently, bi-allelic variants in TBC1D23 have been reported as the underlying molecular defect in seven index cases with a suspected non-degenerative form of PCH, PCH type 11 (PCH11). We used exome sequencing to investigate an individual with global developmental delay, ataxia, seizures, and progressive PCH. Brain volume was evaluated over a disease course of 14 years using volumetric magnetic resonance imaging (MRI). Volume alterations were compared to age-matched controls as well as data from children with PCH2. We identified a homozygous frameshift variant in exon 9 of 18 of TBC1D23 predicting a loss of protein function. Brain morphometry revealed a pattern of pontine, brain stem, and supratentorial volume loss similar to PCH2 patients although less pronounced. Intriguingly, cerebral MRI findings at the age of 1 and 15 years clearly showed progressive atrophy of the cerebellum, especially the hemispheres. In four of the cases reported in the literature cerebellar hemispheres could be evaluated on the MRIs displayed, they also showed atrophic foliae. While pontine hypoplasia and pronounced microcephaly are in line with previous reports on PCH11, our observations of clearly postnatal atrophy of the cerebellum argues for a different pathomechanism than in the other forms of PCH and supports the hypothesis that TBC1D23 deficiency predominantly interferes with postnatal rather than with prenatal cerebellar development.

Neurologic Examination Findings Associated With Small Cerebellar Volumes After Prematurity

To help clinicians understand what to expect from small cerebellar volumes after prematurity, this study aims to characterize the specific impacts of small cerebellar volumes on the infant neurologic examination. A prospective cohort of preterm newborns (<32 weeks' gestational age) had brain magnetic resonance imaging (MRI) studies at term-equivalent age. Cerebellar volumes were compared with neurologic examination findings in follow-up, adjusting for severity of intraventricular hemorrhage, white matter injury, and cerebellar hemorrhage. Deformation-based analyses delineated regional morphometric differences in the cerebellum associated with these findings. Of 119 infants with MRI scans, 109 (92%) had follow-up at 19.0±1.7 months corrected age. Smaller cerebellar volume at term was associated with increased odds of truncal hypotonia, postural instability on standing, and patellar hyperreflexia (P < .03). Small cerebellar volume defined as <19 cm³ by 40 weeks was associated with 7.5-fold increased odds of truncal hypotonia (P < .001), 8.9-fold odds postural instability (P < .001), and 9.7-fold odds of patellar hyperreflexia (P < .001). Voxel-based deformation-based morphometry showed postural instability associated with paravermian regions. Small cerebellar volume is associated with specific abnormalities on neurologic examination by 18 months of age, including truncal tone, reflexes, and postural stability.

YAP1 is involved in replenishment of granule cell precursors following injury to the neonatal cerebellum

The cerebellum undergoes major rapid growth during the third trimester and early neonatal stage in humans, making it vulnerable to injuries in pre-term babies. Experiments in mice have revealed a remarkable ability of the neonatal cerebellum to recover from injuries around birth. In particular, recovery following irradiation-induced ablation of granule cell precursors (GCPs) involves adaptive reprogramming of Nestin-expressing glial progenitors (NEPs). Sonic hedgehog signaling is required for the initial step in NEP reprogramming; however, the full spectrum of developmental signaling pathways that promote NEP-driven regeneration is not known. Since the growth regulatory Hippo pathway has been implicated in the repair of several tissue types, we tested whether Hippo signaling is involved in regeneration of the cerebellum. Using mouse models, we found that the Hippo pathway transcriptional co-activator YAP1 (Yes-associated protein 1) but not TAZ (transcriptional coactivator with PDZ binding motif, or WWTR1) is required in NEPs for full recovery of cerebellar growth following irradiation one day after birth. Although Yap1 plays only a minor role during normal development in differentiation of NEPs or GCPs, the size of the cerebellum, and in particular the internal granule cell layer produced by GCPs, is significantly reduced in Yap1 mutants after irradiation, and the organization of Purkinje cells and Bergmann glial fibers is disrupted. The initial proliferative response of Yap1 mutant NEPs to irradiation is normal and the cells migrate to the GCP niche, but subsequently there is increased cell death of GCPs and altered migration of granule cells, possibly due to defects in Bergmann glia. Moreover, loss of Taz along with Yap1 in NEPs does not abrogate regeneration or alter development of the cerebellum. Our study provides new insights into the molecular signaling underlying postnatal cerebellar development and regeneration.

Disrupted cortico-ponto-cerebellar pathway in patients with hemimegalencephaly

OBJECTIVE

Cerebellar dysmaturation and injury is associated with a wide range of neuromotor, neurocognitive and behavioral disorders as well as with preterm birth. We used diffusion tensor MR imaging to investigate a disruption in structural cortico-ponto-cerebellar (CPC) connectivity in children with infantile-onset severe epilepsy.

METHODS

We performed CPC tract reconstructions in 24 hemimegalencephaly (HME) patients, 28 West syndrome (WS) of unknown etiology patients, and 25 pediatric disease control subjects without a history of epilepsy nor brain abnormality on MRI. To identify the CPC tract, we placed a seeding ROI separately in each right and left cerebral peduncle. We evaluated the distribution patterns of the CPC tracts to the cerebellum and their correlation with clinical findings.

RESULTS

In control and WS of unknown etiology groups, both sides' CPC tracts descended to bilateral hemispheres in 20 (80.0%) and 21 (75.0%); mixed (bilateral on one side and unilateral on the other side) in five (20.0%) and five (17.9%); and unilateral in zero (0.0%) and two (7.1%), respectively. However, in the HME, both sides' CPC tracts descended to bilateral hemispheres in four (16.7%); mixed in 13 (54.1%); and unilateral in seven (29.2%). These CPC patterns differed significantly between the HME and other groups (p < 0.001). Among HME patients, those with a unilateral cerebellar distribution on both sides had significantly earlier seizure onset (p = 0.049) and more frequent seizures (p = 0.052) at a trend level compared to those with bilateral and mixed distributions.

CONCLUSION

Disrupted CPC tracts were observed more frequently in HME patients than in WS of unknown etiology patients and controls, and they may be correlated with earlier seizure onset and more frequent seizures in HME patients. DTI is a useful and non-invasive method for speculating the pathology in the developing brain.

Corpus callosum and cerebellar vermis size in very preterm infants: Relationship to long-term neurodevelopmental outcome

BACKGROUND

The neonatal changes of corpus callosum or cerebellar volume in preterm infants have been shown to link with abnormal mentality and motor disability in early childhood. This study aims to predict the long-term neurological outcomes by measuring these changes on neonatal brain ultrasound in preterm infants.

METHODS

Our cohort consisted of infants aged below 32 weeks' gestation with very low birth body weights who completed neuro-assessments at 5 years of age. Corpus callosum or cerebellar vermis were measured at 28-30 weeks and at 37-40 weeks gestational age in premature infants with cerebral palsy (CP), mental retardation (MR) and normal control premature infants.

RESULTS

There are 12 patients in MR group, 12 in CP group and 27 patients as controls for final analysis. There was no significant difference in other factors between study groups except lower gestational age (P = 0.043) in CP group. Respiratory distress syndrome was more common in MR group (P = 0.037) and cystic periventricular leukomalacia was more common in CP group (P < 0.001) than controls. After adjusting for sex and birth body weight, the MR group had smaller cerebellar vermis area at 37-40 gestational weeks (P = 0.002) than controls. They also reduced the growth of corpus callosum area (difference = -0.12 ± 0.16, P = 0.029) and cerebellar vermis area (difference = 1.10 ± 0.44, P = 0.020) from 28 to 30 gestational weeks to 37-40 gestational weeks compared with controls (difference = 0.03 ± 0.15, 1.92 ± 0.70, respectively). In contrast, the CP group had reduced the growth of corpus callosum body (difference = -0.02 ± 0.18, P = 0.034) compared with controls (difference = 0.03 ± 0.04). They subsequently had smaller body thickness of corpus callosum (0.10 ± 0.02, P = 0.015) at 37-40 gestational weeks than controls (0.14 ± 0.04).

CONCLUSIONS

Serial monitoring corpus callosum and cerebellar vermis size in early life of very preterm babies may predict the motor or mentality neurological outcome at 5 years of age.

Cerebellar Functional Connectivity in Term- and Very Preterm-Born Infants

Cortical resting state networks have been consistently identified in infants using resting state-functional connectivity magnetic resonance imaging (rs-fMRI). Comparable studies in adults have demonstrated cerebellar components of well-established cerebral networks. However, there has been limited investigation of early cerebellar functional connectivity. We acquired non-sedated rs-fMRI data in the first week of life in 57 healthy, term-born infants and at term-equivalent postmenstrual age in 20 very preterm infants (mean birth gestational age 27 ± 2 weeks) without significant cerebral or cerebellar injury. Seed correlation analyses were performed using regions of interests spanning the cortical and subcortical gray matter and cerebellum. Parallel analyses were performed using rs-fMRI data acquired in 100 healthy adults. Our results demonstrate that cortico-cerebellar functional connectivity is well-established by term. Intra- and cortico-cerebellar functional connectivity were largely similar in infants and adults. However, infants showed more functional connectivity structure within the cerebellum, including stronger homotopic correlations and more robust anterior-posterior anticorrelations. Prematurity was associated with reduced correlation magnitudes, but no alterations in intra- and cortico-cerebellar functional connectivity topography. These results add to the growing evidence that the cerebellum plays an important role in shaping early brain development during infancy.

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

Objectives

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

Study design

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

Results

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

Conclusions

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

Cerebellar hypoplasia of prematurity: Causes and consequences

As magnetic resonance imaging has been increasingly used to study brain injury and brain development in premature newborns, the prevalence of cerebellar abnormalities is increasingly recognized. The preterm cerebellum is highly vulnerable to a number of insults during its critical phase of growth and development throughout the period of prematurity and beyond. Direct cerebellar injury and additional factors such as supratentorial brain injury and glucocorticoid exposure adversely impact cerebellar growth and, consequently, increase the risk of neurodevelopmental disabilities. In this chapter the causes and consequences of cerebellar hypoplasia of prematurity are reviewed.

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.

Longitudinal Preterm Cerebellar Volume: Perinatal and Neurodevelopmental Outcome Associations

Impaired cerebellar development is an important determinant of adverse motor and cognitive outcomes in very preterm (VPT) infants. However, longitudinal MRI studies investigating cerebellar maturation from birth through childhood and associated neurodevelopmental outcomes are lacking. We aimed to compare cerebellar volume and growth from term-equivalent age (TEA) to 7 years between VPT (< 30 weeks' gestation or < 1250 g) and full-term children; and to assess the association between these measures, perinatal factors, and 7-year outcomes in VPT children, and whether these relationships varied by sex. In a prospective cohort study of 224 VPT and 46 full-term infants, cerebellar volumes were measured on MRI at TEA and 7 years. Useable data at either time-point were collected for 207 VPT and 43 full-term children. Cerebellar growth from TEA to 7 years was compared between VPT and full-term children. Associations with perinatal factors and 7-year outcomes were investigated in VPT children. VPT children had smaller TEA and 7-year volumes and reduced growth. Perinatal factors were associated with smaller cerebellar volume and growth between TEA and 7 years, namely, postnatal corticosteroids for TEA volume, and female sex, earlier birth gestation, white and deep nuclear gray matter injury for 7-year volume and growth. Smaller TEA and 7-year volumes, and reduced growth were associated with poorer 7-year IQ, language, and motor function, with differential relationships observed for male and female children. Our findings indicate that cerebellar growth from TEA to 7 years is impaired in VPT children and relates to early perinatal factors and 7-year outcomes.

Neonatal brain injury causes cerebellar learning deficits and Purkinje cell dysfunction

Premature infants are more likely to develop locomotor disorders than term infants. In a chronic sub-lethal hypoxia (Hx) mouse model of neonatal brain injury, we recently demonstrated the presence of cellular and physiological changes in the cerebellar white matter. We also observed Hx-induced delay in Purkinje cell (PC) arborization. However, the behavioral consequences of these cellular alterations remain unexplored. Using the Erasmus Ladder to study cerebellar behavior, we report the presence of locomotor malperformance and long-term cerebellar learning deficits in Hx mice. Optogenetics experiments in Hx mice reveal a profound reduction in spontaneous and photoevoked PC firing frequency. Finally, treatment with a gamma-aminobutyric acid (GABA) reuptake inhibitor partially rescues locomotor performance and improves PC firing. Our results demonstrate a long-term miscoordination phenotype characterized by locomotor malperformance and cerebellar learning deficits in a mouse model of neonatal brain injury. Our findings also implicate the developing GABA network as a potential therapeutic target for prematurity-related locomotor deficits.

Damaging de novo mutations diminish motor skills in children on the autism spectrum

Genetics is a major determining factor in autism spectrum disorder (ASD). To date, only the most severe class of de novo mutation, likely gene disruptive (LGD), has been correlated with IQ, a phenotypic characteristic associated with ASD, but not a core feature. A less severe class of de novo mutation, missense, while enriched in individuals with ASD, has been refractory to correlation with any ASD phenotypic feature. In this report, we demonstrate that de novo LGD and missense mutations scored by target gene vulnerability both show significant associations with diminished motor skills.

In individuals with autism spectrum disorder (ASD), de novo mutations have previously been shown to be significantly correlated with lower IQ but not with the core characteristics of ASD: deficits in social communication and interaction and restricted interests and repetitive patterns of behavior. We extend these findings by demonstrating in the Simons Simplex Collection that damaging de novo mutations in ASD individuals are also significantly and convincingly correlated with measures of impaired motor skills. This correlation is not explained by a correlation between IQ and motor skills. We find that IQ and motor skills are distinctly associated with damaging mutations and, in particular, that motor skills are a more sensitive indicator of mutational severity than is IQ, as judged by mutational type and target gene. We use this finding to propose a combined classification of phenotypic severity: mild (little impairment of either), moderate (impairment mainly to motor skills), and severe (impairment of both IQ and motor skills).

Cerebellar injury in preterm infants

Although preterm birth is best known to result in adverse neurodevelopmental outcomes through injury of the supratentorial structures, including intraventricular hemorrhage and periventricular leukomalacia, the cerebellum has become increasingly recognized as an important target for injury and adverse motor and cognitive outcomes. Undergoing the most dramatic growth during the preterm period, the cerebellum is vulnerable to large and small hemorrhages, as well as hypoplasia resulting from a number of potentially modifiable risk factors. These factors include contact with intraventricular blood, crossed cerebrocerebellar diaschisis, postnatal glucocorticoid exposure, pain and opioid exposure, nutrition and somatic growth, cardiorespiratory factors, and socioeconomic status. Strategies targeting these factors may result in prevention of the motor and cognitive deficits seen after cerebellar hemorrhage or hypoplasia.

Effect of rhythmic auditory cueing on gait in cerebral palsy: a systematic review and meta-analysis

Auditory entrainment can influence gait performance in movement disorders. The entrainment can incite neurophysiological and musculoskeletal changes to enhance motor execution. However, a consensus as to its effects based on gait in people with cerebral palsy is still warranted. A systematic review and meta-analysis were carried out to analyze the effects of rhythmic auditory cueing on spatiotemporal and kinematic parameters of gait in people with cerebral palsy. Systematic identification of published literature was performed adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses and American Academy for Cerebral Palsy and Developmental Medicine guidelines, from inception until July 2017, on online databases: Web of Science, PEDro, EBSCO, Medline, Cochrane, Embase and ProQuest. Kinematic and spatiotemporal gait parameters were evaluated in a meta-analysis across studies. Of 547 records, nine studies involving 227 participants (108 children/119 adults) met our inclusion criteria. The qualitative review suggested beneficial effects of rhythmic auditory cueing on gait performance among all included studies. The meta-analysis revealed beneficial effects of rhythmic auditory cueing on gait dynamic index (Hedge's g=0.9), gait velocity (1.1), cadence (0.3), and stride length (0.5). This review for the first time suggests a converging evidence toward application of rhythmic auditory cueing to enhance gait performance and stability in people with cerebral palsy. This article details underlying neurophysiological mechanisms and use of cueing as an efficient home-based intervention. It bridges gaps in the literature, and suggests translational approaches on how rhythmic auditory cueing can be incorporated in rehabilitation approaches to enhance gait performance in people with cerebral palsy.

Cerebellar-dependent associative learning is impaired in very preterm born children and young adults

Preterm birth incorporates an increased risk for cerebellar developmental disorders likely contributing to motor and cognitive abnormalities. Experimental evidence of cerebellar dysfunction in preterm subjects, however, is sparse. In this study, classical eyeblink conditioning was used as a marker of cerebellar dysfunction. Standard delay conditioning was investigated in 20 adults and 32 preschool children born very preterm. Focal lesions were excluded based on structural magnetic resonance imaging. For comparison, an equal number of matched term born healthy peers were tested. Subgroups of children (12 preterm, 12 controls) were retested. Preterm subjects acquired significantly less conditioned responses (CR) compared to controls with slower learning rates. A likely explanation for these findings is that preterm birth impedes function of the cerebellum even in the absence of focal cerebellar lesions. The present findings are consistent with the assumption that prematurity results in long-term detrimental effects on the integrity of the cerebellum. It cannot be excluded, however, that extra-cerebellar pathology contributed to the present findings.

Systemic inflammation combined with neonatal cerebellar haemorrhage aggravates long-term structural and functional outcomes in a mouse model

BACKGROUND

Despite the increased recognition of cerebellar injury in survivors of preterm birth, the neurodevelopmental consequences of isolated cerebellar injury have been largely unexplored and our current understanding of the functional deficits requires further attention in order to translate knowledge to best practices. Preterm infants are exposed to multiple stressors during their postnatal development including perinatal cerebellar haemorrhage (CBH) and postnatal infection, two major risk factors for neurodevelopmental impairments.

METHODS

We developed a translational mouse model of CBH and/or inflammation to measure the short- and long-term outcomes in cerebellar structure and function.

RESULTS

Mice exposed to early combined insults of CBH and early inflammatory state (EIS) have a delay in grasping acquisition, neonatal motor deficits and deficient long-term memory. CBH combined with late inflammatory state (LIS) does not induce neonatal motor problems but leads to poor fine motor function and long-term memory deficits at adulthood. Early combined insults result in poor cerebellar growth from postnatal day 15 until adulthood shown by MRI, which are reflected in diminished volumes of cerebellar structures. There are also decreases in volumes of gray matter and hippocampus. Cerebellar microgliosis appears 24h after the combined insults and persists until postnatal day 15 in the cerebellar molecular layer and cerebellar nuclei in association with a disrupted patterning of myelin deposition, a delay of oligodendrocyte maturation and reduced white matter cerebellar volume.

CONCLUSIONS

Together, these findings reveal poor outcomes in developing brains exposed to combined cerebellar perinatal insults in association with cerebellar hypoplasia, persistence of microgliosis and alterations of cerebellar white matter maturation and growth.

Higher growth, fat and fat-free masses correlate with larger cerebellar volumes in preterm infants at term

AIM

Smaller cerebellar volumes in very low-birthweight (VLBW) infants at term have been related to adverse cognitive outcomes, and this study evaluated whether these volumes were associated with a growth in body composition during hospital stays.

METHODS

We prospectively recruited 42 VLBW infants from an Italian neonatal unit between January 2013 and August 2015. Cerebellar volumes and body composition were measured by magnetic resonance imaging (MRI) and air-displacement plethysmography, respectively, at 40 weeks of gestational age and anthropometric and nutritional data were collected. We also included 20 term-born controls.

RESULTS

The mean gestational age and birthweight of the VLBW infants were 29.4 (±1.9) weeks and 1120 (±290) g. There was a positive correlation between cerebellar volumes and daily weight gain from birth to term (R² = 0.26, p = 0.001), weight (R² = 0.25, p = 0.001), length (R² = 0.16, p = 0.01), fat mass (R² = 0.15, p = 0.01) and fat-free mass at term (R² = 0.20, p = 0.003). In multiple regression analysis, daily weight gain, mechanical ventilation and postconceptional age at MRI were independently associated with cerebellar volumes. Anthropometric data and cerebellar volumes were similar between VLBW and control infants.

CONCLUSION

Higher growth, higher fat mass and fat-free mass were associated with larger cerebellar volumes in VLBW infants at term.

A rare case of cerebellar agenesis: a probabilistic Constrained Spherical Deconvolution tractographic study

Aim of this study is to show the potential of probabilistic tractographic techniques, based on the Constrained Spherical Deconvolution (CSD) algorithms, in recognizing white matter fiber bundle anomalies in patients with complex cerebral malformations, such as cerebellar agenesis. The morphological and tractographic study of a 17-year-old male patient affected by cerebellar agenesis was performed by using a 3Tesla MRI scanner. Genetic and neuropsychological tests were carried out. An MRI morphological study showed the absence of both cerebellar hemispheres and the flattening of the anterior side of the pons. Moreover, it showed a severe vermian hypoplasia with a minimal vermian residual. The study recognized two thin cerebellar remnants, medially in contact with the small vermian residual, at the pontine level. The third ventricle, morphologically normal, communicated with a permagna cerebello-medullary cistern. Probabilistic CSD tractography identified some abnormal and aberrant infratentorial tracts, symmetrical on both sides. In particular, the transverse pontine fibers were absent and the following tracts with aberrant trajectories have been identified: "cerebello-thalamic" tracts; "fronto-cerebellar" tracts; and ipsilateral and contralateral "spino-cerebellar" tracts. Abnormal tracts connecting the two thin cerebellar remnants have also been detected. There were no visible alterations in the main supratentorial tracts in either side. Neuropsychiatric evaluation showed moderate cognitive-motor impairment with discrete adaptive compensation. Probabilistic CSD tractography is a promising technique that overcome reconstruction biases of other diffusion tensor-based approaches and allowed us to recognize, in a patient with cerebellar agenesis, abnormal tracts and aberrant trajectories of normally existing tracts.

Cranial ultrasonography of the immature cerebellum: Role and limitations

Cranial ultrasonography (CUS) is a reliable and non-invasive tool to detect frequently occurring brain abnormalities and to monitor brain development and maturation in high risk neonates. Standard CUS views are obtained through the anterior fontanel. However, evaluation of the posterior fossa is often suboptimal with this approach. Cerebellar injury occurs frequently in preterm infants and has important prognostic consequences. Early detection is therefore important. This review focuses on techniques that optimize the performance of CUS when studying the preterm cerebellum, including the use of the mastoid fontanel and the adaptation of focus points and scan frequencies. For illustration, CUS images of the normal posterior fossa anatomy as well as examples of abnormalities that may be encountered in preterm infants are included. We also discuss the limitations of CUS and the role of magnetic resonance imaging.

Early general movements and brain magnetic resonance imaging at term-equivalent age in infants born <30weeks' gestation

BACKGROUND

Neurodevelopmental assessments and brain magnetic resonance imaging (MRI) at term-equivalent age (TEA) predict developmental outcomes in preterm infants. However, the relationship between neurodevelopment prior to term and cerebral structure is currently unknown.

AIMS

To examine the relationships between General Movements (GMs) assessed from birth to TEA and brain MRI at TEA in infants born <30weeks' gestation.

STUDY DESIGN

Prospective cohort study. GMs (categorised as 'normal' or 'abnormal') were recorded weekly from birth to 32weeks, and at 34 and 36weeks' postmenstrual age. At TEA, GMs were assessed concurrently with brain MRI (using a validated scoring system).

SUBJECTS

149 infants born <30weeks' gestation were recruited from a tertiary hospital.

RESULTS

103 infants had MRI at TEA and GMs recorded. Abnormal GMs prior to term were associated with cortical grey matter abnormality (p<0.03), deep grey matter abnormality (p=0.02) and increased interhemispheric distance (p<0.02). Abnormal GMs at TEA (n=55/90) were associated with more global brain abnormality (p<0.01) and cortical grey matter abnormality (p=0.01), and decreased transcerebellar diameter (p=0.04) on concurrent brain MRI.

CONCLUSIONS

Abnormal GMs both prior to term and at TEA were associated with more marked brain abnormality, and smaller brains at TEA. Abnormal GMs are an early marker of brain abnormalities in very preterm infants.

Cerebello-cerebral connectivity in the developing brain

Disrupted cerebellar development and injury is associated with impairments in both motor and non-motor domains. Methods to non-invasively characterize cerebellar afferent and efferent connections during early development are lacking. The aim of this study was to assess the feasibility of delineating cortico-ponto-cerebellar (CPC) and cerebello-thalamo-cortical (CTC) white matter tracts during brain development using high angular resolution diffusion imaging (HARDI). HARDI data were obtained in 24 infants born between 24⁺⁶ and 39 weeks gestational age (median 33⁺⁴ weeks) and scanned between 29⁺¹ and 44 weeks postmenstrual age (PMA) (median 37⁺¹ weeks). Probabilistic tractography of CPC and CTC fibers was performed using constrained spherical deconvolution. Connections between cerebellum and contralateral cerebral hemisphere were identified in all infants studied. Fractional anisotropy (FA) values of CTC and CPC pathways increased with increasing PMA at scan (p < 0.001). The supratentorial regions connecting to contralateral cerebellum in most subjects, irrespective of PMA at scan, included the precentral cortex, superior frontal cortex, supplementary motor area, insula, postcentral cortex, precuneus, and paracentral lobule. This study demonstrates the feasibility of assessing CTC and CPC white matter connectivity in vivo during the early stages of development. The ability to assess cerebellar connectivity during this critical developmental period may help improve our understanding of the role of the cerebellum in a wide range of neuromotor and neurocognitive disorders.

Tract Profiles of the Cerebellar White Matter Pathways in Children and Adolescents

Intact development of cerebellar connectivity is essential for healthy neuromotor and neurocognitive development. To date, limited knowledge about the microstructural properties of the cerebellar peduncles, the major white matter tracts of the cerebellum, is available for children and adolescents. Such information would be useful as a comparison for studies of normal development, clinical conditions, or associations of cerebellar structures with cognitive and motor functions. The goal of the present study was to evaluate the variability in diffusion measures of the cerebellar peduncles within individuals and within a normative sample of healthy children. Participants were 19 healthy children and adolescents, aged 9-17 years, mean age 13.0 ± 2.3. We analyzed diffusion magnetic resonance imaging (dMRI) data with deterministic tractography. We generated tract profiles for each of the cerebellar peduncles by extracting four diffusion properties (fractional anisotropy (FA) and mean, radial, and axial diffusivity) at 30 equidistant points along each tract. We were able to identify the middle cerebellar peduncle and the bilateral inferior and superior cerebellar peduncles in all participants. The results showed that within each of the peduncles, the diffusion properties varied along the trajectory of the tracts. However, the tracts showed consistent patterns of variation across individuals; the coefficient of variation for FA across individual profiles was low (≤20%) for each tract. We observed no systematic variation of the diffusion properties with age. These cerebellar tract profiles of the cerebellar peduncles can serve as a reference for future studies of children across the age range and for children and adolescents with clinical conditions that affect the cerebellum.

Brain Volumes at Term-Equivalent Age in Preterm Infants: Imaging Biomarkers for Neurodevelopmental Outcome through Early School Age

OBJECTIVE

To evaluate the relationship between brain volumes at term and neurodevelopmental outcome through early school age in preterm infants.

STUDY DESIGN

One hundred twelve preterm infants (born mean gestational age 28.6 ± 1.7 weeks) were studied prospectively with magnetic resonance imaging (imaged at mean 41.6 ± 1.0 weeks). T2- and T1-weighted images were automatically segmented, and volumes of 6 tissue types were related to neurodevelopmental outcome assessed using the Bayley Scales of Infant and Toddler Development, Third Edition (cognitive, fine, and gross motor scores) at 24 months corrected age (n = 112), Griffiths Mental Development Scales (developmental quotient) at age 3.5 years (n = 98), Movement Assessment Battery for Children, Second Edition (n = 85), and Wechsler Preschool and Primary Scale of Intelligence, Third Edition at age 5.5 years (n = 44). Corrections were made for intracranial volume, maternal education, and severe brain lesions.

RESULTS

Ventricular volumes were negatively related to neurodevelopmental outcome at age 24 months and 3.5 years, as well as processing speed at age 5.5 years. Unmyelinated white matter (UWM) volume was positively associated with motor outcome at 24 months and with processing speed at age 5.5 years. Cortical gray matter (CGM) volume demonstrated a negative association with motor performance and cognition at 24 months and with developmental quotient at age 3.5 years. Cerebellar volume was positively related to cognition at these time points. Adjustment for brain lesions attenuated the relations between cerebellar and CGM volumes and cognition.

CONCLUSIONS

Brain volumes of ventricles, UWM, CGM, and cerebellum may serve as biomarkers for neurodevelopmental outcome in preterm infants. The relationship between larger CGM volumes and adverse neurodevelopment may reflect disturbances in neuronal and/or axonal migration at the UWM-CGM boundary and warrants further investigation.

Very Early Brain Damage Leads to Remodeling of the Working Memory System in Adulthood: A Combined fMRI/Tractography Study

The human brain can adapt to overcome injury even years after an initial insult. One hypothesis states that early brain injury survivors, by taking advantage of critical periods of high plasticity during childhood, should recover more successfully than those who suffer injury later in life. This hypothesis has been challenged by recent studies showing worse cognitive outcome in individuals with early brain injury, compared with individuals with later brain injury, with working memory particularly affected. We invited individuals who suffered perinatal brain injury (PBI) for an fMRI/diffusion MRI tractography study of working memory and hypothesized that, 30 years after the initial injury, working memory deficits in the PBI group would remain, despite compensatory activation in areas outside the typical working memory network. Furthermore we hypothesized that the amount of functional reorganization would be related to the level of injury to the dorsal cingulum tract, which connects medial frontal and parietal working memory structures. We found that adults who suffered PBI did not significantly differ from controls in working memory performance. They exhibited less activation in classic frontoparietal working memory areas and a relative overactivation of bilateral perisylvian cortex compared with controls. Structurally, the dorsal cingulum volume and hindrance-modulated orientational anisotropy was significantly reduced in the PBI group. Furthermore there was uniquely in the PBI group a significant negative correlation between the volume of this tract and activation in the bilateral perisylvian cortex and a positive correlation between this activation and task performance. This provides the first evidence of compensatory plasticity of the working memory network following PBI.

Co-occurrence of developmental and behavioural problems in moderate to late preterm-born children

OBJECTIVE

To determine the occurrence of emotional and behavioural problems (EBP) in moderate to late preterm (MLP) and full-term children with developmental delay.

DESIGN

Participants were recruited from 13 randomly selected preventive child healthcare (PCH) centres in the Netherlands. We included 903 MLP children of 32-36 weeks' gestation and 538 full-term controls, born between January 2002 and June 2003. Parents completed the Ages and Stages Questionnaire (ASQ) and Child Behaviour Checklist (CBCL) shortly before the scheduled PCH visit at 4 years of age. Co-occurrence was defined as: ASQ total or domain score >2 SDs below the mean and a CBCL score >84th percentile on total problems, internalising (emotional) or externalising (behavioural) problems.

RESULTS

EBP were more prevalent among MLP children with abnormal ASQ total problems scores than among full-term children, particularly regarding externalising problems (33.8% vs 23.8%). In MLP children, rates of EBP differed per developmental domain and were highest for the domains problem-solving (36.0% had externalising problems, 95% CI 24.1% to 49.9%) and personal-social skills (38.7% had internalising problems, 95% CI 26.4% to 52.8%). The risk of any type of co-occurrence was higher for MLP than for full-term children (OR 1.86; 95% CI 1.14 to 3.03). Independent risk factors for co-occurrence were male gender, low socioeconomic status and young maternal age.

CONCLUSIONS

Up to 39% of 4-year-old MLP children with developmental delay also have EBP, indicating that increased awareness of EBP is warranted in MLP children with developmental delay. Further research is needed to determine whether early detection of co-occurring problems results in better long-term health.

Clinical and neuroimaging features as diagnostic guides in neonatal neurology diseases with cerebellar involvement

Cerebellar abnormalities are encountered in a high number of neurological diseases that present in the neonatal period. These disorders can be categorized broadly as inherited (e.g. malformations, inborn errors of metabolism) or acquired (e.g. hemorrhages, infections, stroke). In some disorders such as Dandy-Walker malformation or Joubert syndrome, the main abnormalities are located within the cerebellum and brainstem. In other disorders such as Krabbe disease or sulfite oxidase deficiency, the main abnormalities are found within the supratentorial brain, but the cerebellar involvement may be helpful for diagnostic purposes. In In this article, we review neurological disorders with onset in the neonatal period and cerebellar involvement with a focus on how characterization of cerebellar involvement can facilitate accurate diagnosis and improved accuracy of neuro-functional prognosis.

Developmental cerebellar cognitive affective syndrome in ex-preterm survivors following cerebellar injury

Cerebellar injury is increasingly recognized as an important complication of very preterm birth. However, the neurodevelopmental consequences of early life cerebellar injury in prematurely born infants have not been well elucidated. We performed a literature search of studies published between 1997 and 2014 describing neurodevelopmental outcomes of preterm infants following direct cerebellar injury or indirect cerebellar injury/underdevelopment. Available data suggests that both direct and indirect mechanisms of cerebellar injury appear to stunt cerebellar growth and adversely affect neurodevelopment. This review also provides important insights into the highly integrated cerebral-cerebellar structural and functional correlates. Finally, this review highlights that early life impairment of cerebellar growth extends far beyond motor impairments and plays a critical, previously underrecognized role in the long-term cognitive, behavioral, and social deficits associated with brain injury among premature infants. These data point to a developmental form of the cerebellar cognitive affective syndrome previously described in adults. Longitudinal prospective studies using serial advanced magnetic resonance imaging techniques are needed to better delineate the full extent of the role of prematurity-related cerebellar injury and topography in the genesis of cognitive, social-behavioral dysfunction.

Maternal Postsecondary Education Associated With Improved Cerebellar Growth After Preterm Birth

The preterm cerebellum is vulnerable to impaired development impacting long-term outcome. Preterm newborns (<32 weeks) underwent serial magnetic resonance imaging (MRI) scans. The association between parental education and cerebellar volume at each time point was assessed, adjusting for age at scan. In 26 infants, cerebellar volumes at term (P = .001), but not birth (P = .4), were associated with 2-year volumes. For 1 cm(3) smaller cerebellar volume (4% total volume) at term, the cerebellum was 3.18 cm(3) smaller (3% total volume) by 2 years. Maternal postsecondary education was not associated with cerebellar volume at term (P = .16). Maternal postsecondary education was a significant confounder in the relationship between term and 2-year cerebellar volumes (P = .016), with higher education associated with improved volumes by 2 years. Although preterm birth has been found to be associated with smaller cerebellar volumes at term, maternal postsecondary education is associated with improved growth detectable by 2 years.

The neurological outcomes of cerebellar injury in premature infants

AIM

Cerebellar injury is a characteristic injury associated with preterm infants. However, the impact of cerebellar injury on the development of preterm infants is unclear.

METHOD

We reviewed magnetic resonance image studies of preterm infants with cerebral palsy retrospectively and evaluated the developmental outcomes.

RESULTS

Cerebellar injury was recognized in 9 (2.4%) of 381 patients with cerebral palsy who were born preterm. The median gestational age was 26 (range 23-32) weeks and the median birth weight was 938 (range 492-1450) g. Seven of the nine patients had severe symmetric injuries to the inferior cerebellar hemispheres, resulting in a pancake-like appearance of the residual upper cerebellum. Supratentorial lesions were also recognized: periventricular leukomalacia in seven; atrophy of the basal ganglia in two; and intraventricular hemorrhage in two. Importantly, the motor dysfunction was related to the reduction in the white matter volume and severity of basal ganglia atrophy, but not to the cerebellar injury. Four of the nine patients could walk without limitations despite extensive cerebellar disruption. Only four patients could speak meaningful words during the study and only one spoke two-word sentences.

INTERPRETATION

The patients with cerebellar injury might have a communication handicap, rather than altered motor function. Prematurity-related cerebellar complications require more attention in terms of cognitive and speech function, in addition to neuromotor development.

Cerebellar injury in preterm children with cerebral palsy after intraventricular hemorrhage: Prevalence and relationship to functional outcomes

OBJECTIVES

To elucidate the prevalence of cerebellar injury and its relationship to functional outcomes in preterm children with cerebral palsy (CP) after intraventricular hemorrhage (IVH).

PARTICIPANTS

We selected 69 children (40 males and 29 females, aged between 6 and 13 years) out of 2049 with cerebral palsy who visited Morinomiya Hospital, the regional center hospital for CP in West Japan. The inclusion criteria were (1) gestational age under 36 weeks at birth, (2) clear history of postnatal intraventricular hemorrhage, and (3) age at investigation over 6 years old. Those without sufficient imaging study or functional evaluation were excluded.

METHODS

The participants were divided into four groups according to the presence of post-hemorrhagic hydrocephalus (PH) and cerebellar injury (CI): PH+/CI+, PH+/CI-, PH-/CI+, and PH-/CI-. Type of CP, ability to walk, verbal function, the incidence of severe visual impairment, and the complication of epilepsy were investigated and compared among the groups.

RESULTS

The gestational ages of the participants were between 22 and 34 weeks, and their birth weight was between 412 and 1788 g. PH and CI were found in 39 (57%) and 40 (58%) children, respectively. Both the PH+/CI+ group (n=31) and the PH-/CI+ group (n=9) showed significantly lower walking and verbal abilities and a higher incidence of epilepsy than the PH-/CI- group (n=21), while the PH+/CI- group showed no significant difference from the PH-/CI- group. Severe visual impairment was found only in the PH+/CI+ group and the PH-/CI+ group.

CONCLUSIONS

The prevalence of CI in preterm children with CP after IVH (58%) was almost the same as that of PH. CI is one of the most significant complications in preterm infants, affecting motor and verbal functions and being associated with epilepsy more than PH.

Low-grade intraventricular hemorrhage disrupts cerebellar white matter in preterm infants: evidence from diffusion tensor imaging

INTRODUCTION

Recent diffusion tensor imaging (DTI) studies have demonstrated that leakage of hemosiderin into cerebrospinal fluid (CSF), which is caused by high-grade intraventricular hemorrhage (IVH), can affect cerebellar development in preterm born infants. However, a direct effect of low-grade IVH on cerebellar development is unknown. Thus, we evaluated the cerebellar and cerebral white matter (WM) of preterm infants with low-grade IVH.

METHODS

Using DTI tractography performed at term-equivalent age, we analyzed 42 infants who were born less than 30 weeks gestational age (GA) at birth (22 with low-grade IVH, 20 without). These infants were divided into two birth groups depending on GA, and we then compared the presence and absence of IVH which was diagnosed by cerebral ultrasound (CUS) within 10 days after birth or conventional magnetic resonance imaging (MRI) at term-equivalent age in each group. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) at the superior cerebellar peduncle (SCP), middle cerebellar peduncle (MCP), motor tract, and sensory tract were measured.

RESULTS

In the SCP, preterm born infants with IVH had lower FA values compared with infants without IVH. In particular, younger preterm birth with IVH had lower FA values in the SCP and motor tract and higher ADC values in the MCP.

CONCLUSION

Low-grade IVH impaired cerebellar and cerebral WM, especially in the SCP. Moreover, younger preterm infants exhibited greater disruptions to cerebellar WM and the motor tract than infants of older preterm birth.

Neonatal neuropsychology: emerging relations of neonatal sensory-motor responses to white matter integrity

The neonatal period is considered to be essential for neurodevelopment and wellbeing throughout the life span, yet little is known about brain-behavior relationships in the neonatal period. The aim of this study was to evaluate the association between neonatal sensory-motor regulation and white-matter (WM) integrity of major fiber tracts in the neonatal period. We hypothesized that WM integrity of sensory-motor systems would predict neurobehavioral maturation during the first month of life. Forty-nine premature neonates underwent magnetic-resonance-imaging at term. Diffusion-tensor-imaging analysis was performed in major WM tracts along with repeated neonatal neurobehavioral evaluations assessing sensory reactivity and motor regulation. Difficulties in one or more behavioral sub-category, mostly in auditory and visual attention, hypotonicity and jitteriness, were documented in 78.3% infants at term. Sixty-six percent of infants experienced difficulties, mostly in auditory attention, head-neck control, hypotonicity and motor asymmetry, at 44 weeks. Attention difficulties were associated with reduced integrity of cerebral and superior cerebellar peduncles; while tonicity was associated with reduced integrity of the corpus-callosum and inferior-posterior tracts. Overall, results showed that early maturing tracts were related with the degree of typicality of sensory reactivity status while late maturing tracts were related with the degree of typicality of tonic regulation. WM integrity and maturation factors explained 40.2% of the variance in neurobehavior at 44 weeks. This study suggests that in preterm neonates, deviant sensory-motor reactivity can be detected very early in development in manners that are related to lower integrity/maturational level of early and late maturing fiber tracts.

Developmental delay in moderately preterm-born children with low socioeconomic status: risks multiply

OBJECTIVE

To assess separate and joint effects of low socioeconomic status (SES) and moderate prematurity on preschool developmental delay.

STUDY DESIGN

Prospective cohort study with a community-based sample of preterm- and term-born children (Longitudinal Preterm Outcome Project). We assessed SES on the basis of education, occupation, and family income. The Ages and Stages Questionnaire was used to assess developmental delay at age 4 years. We determined scores for overall development, and domains fine motor, gross motor, communication, problem-solving, and personal-social of 926 moderately preterm-born (MP) (32-36 weeks gestation) and 544 term-born children. In multivariable logistic regression analyses, we used standardized values for SES and gestational age (GA).

RESULTS

Prevalence rates for overall developmental delay were 12.5%, 7.8%, and 5.6% in MP children with low, intermediate, and high SES, respectively, and 7.2%, 4.0%, and 2.8% in term-born children, respectively. The risk for overall developmental delay increased more with decreasing SES than with decreasing GA, but the difference was not statistically significant: OR (95% CI) for a 1 standard deviation decrease were: 1.62 (1.30-2.03) and 1.34 (1.05-1.69), respectively, after adjustment for sex, number of siblings, and maternal age. No interaction was found except for communication, showing that effects of SES and GA are mostly multiplicative.

CONCLUSIONS

Low SES and moderate prematurity are separate risk factors with multiplicative effects on developmental delay. The double jeopardy of MP children with low SES needs special attention in pediatric care.