Abnormal cerebral MRI findings and neuroimpairments in very low birth weight (VLBW) adolescents

Brain MRI findings and their association with visual impairment in young adolescents born very preterm

PURPOSE

Very preterm birth increases risk for neonatal white matter injury, but there is limited data on to what extent this persists into adolescence and how this relates to ophthalmological outcomes. The aim of this study was to assess brain MRI findings in 12-year-old children born very preterm compared to controls and their association with concurrent ophthalmological outcomes.

METHODS

We included 47 children born very preterm and 22 full-term controls (gestational age <32 and >37 weeks, respectively). Brain MRI findings were studied in association with concurrent ophthalmological outcomes at 12-year follow-up.

RESULTS

Evans index (0.27 vs 0.25, p<0.001) and a proposed "posterior ventricle index" (0.47 vs 0.45, p=0.018) were increased in children born very preterm. Higher gestational age associated with larger corpus callosum area (β=10.7, 95%CI 0.59-20.8). Focal white matter lesions were observed in 15 (32%) of very preterm children and in 1 (5%) of full-term controls. Increased posterior ventricle index increased risk for visual acuity ≤1.0 (OR=1.07×1011, 95%CI=7.78-1.48×1021) and contrast sensitivity <0.5 (OR=2.6×1027, 95%CI=1.9×108-3.5×1046). Decreased peritrigonal white matter thickness associated with impaired visual acuity (β=0.04, 95%CI 0.002-0.07).

CONCLUSION

More white matter lesions and evidence of lower white matter volume were found in children born very preterm compared with full-term controls at 12-year follow-up. The association between larger posterior ventricle index and reduced visual acuity and contrast sensitivity suggests disturbances of the posterior visual pathway due to diffuse white matter lesions.

Multidisciplinary and neuroimaging findings in preterm born very low birthweight individuals from birth to 28 years of age: A systematic review of a Norwegian prospective cohort study

BACKGROUND

Children born preterm with very low birthweight (VLBW) face long-lasting neurodevelopmental challenges, where multidisciplinary assessments are warranted. The International Classification of Functioning, Disability and Health (ICF) provides a framework for understanding and conceptualising these outcomes.

OBJECTIVES

We aimed to review clinical and neuroimaging findings from birth to adulthood in a Norwegian cohort of individuals born preterm with VLBW (gestational age <37 weeks, birthweight ≤1500 g) within the framework of ICF.

DATA SOURCES

We searched PubMed and Embase for articles reporting results of the Norwegian University of Science and Technology (NTNU) Low Birth Weight in a Lifetime Perspective study.

STUDY SELECTION AND DATA EXTRACTION

We included original articles reporting proportions of adverse outcomes, mean group differences, risk factors or associations between outcomes. Data were extracted according to ICF's two-level classification. Body functions and structures comprised outcomes of brain structures, cognition, mental health, vision, pain and physical health. Activities and participation comprised motor skills, general and social functioning, education, employment, and health-related quality of life.

SYNTHESIS

We performed a qualitative synthesis of included articles. Where mean (SD) was reported, we calculated group differences in SD units.

RESULTS

Fifty-eight publications were included. Within body functions and structures, increased prevalence of brain structure pathology, lower cognitive performance, mental health problems, visual and physical health impairments through childhood, adolescence and young adulthood were reported among preterm VLBW participants compared with controls. Within activities and participation, motor problems, lower general and social functioning, and lower academic attainment were found. Perinatal factors were associated with several outcomes, and longitudinal findings suggested persistent consequences of being born preterm with VLBW.

CONCLUSIONS

Being born preterm with VLBW has long-term influences on body functions and structures, activities and participation. The ICF is appropriate for assessing general domains of functioning and guiding the management of individuals born preterm with VLBW.

Cognitive, academic, executive and psychological functioning in children with spastic motor type cerebral palsy: Influence of extent, location, and laterality of brain lesions

PURPOSE

To investigate, in spastic motor-type cerebral palsy, the association between 1) the location and extent of brain lesions and numerous psychological outcomes; 2) the laterality of brain lesions and performance of verbal-related cognitive functions.

METHODS

The semi-quantitative scale for MRI (sqMRI) was scored for 101 children with cerebral palsy. Non-verbal and verbal proxy intelligence quotients (IQ), word reading, spelling, numerical operations skills, executive functioning, and psychological adjustment were assessed. Relationships between global and regional sqMRI scores and clinical scores were examined. The best multivariable linear regression model for each outcome was identified using the Bayesian Information Criteria. Regional sqMRI scores, gross motor functioning, manual ability, and epilepsy status were considered for inclusion as covariables. Where sqMRI scores made statistically significant contributions to models of verbal-related functioning, data were reanalysed including these sqMRI scores' laterality index. Verbal-related outcomes were compared between participants with left-sided versus bilateral brain lesions.

RESULTS

Medial dorsal thalamus and parietal lobe lesions significantly accounted for poorer verbal proxy-IQ. Left-hemisphere lateralization of temporal lobe lesions was associated with poorer verbal proxy-IQ. Participants with bilateral lesions performed significantly better than those with unilateral left-sided lesions in verbal cognitive functions. Controlling for epilepsy diagnosis, participants with ventral posterior lateral thalamus lesions presented with better Behaviour Rating Inventory of Executive Function scores, although within the normal range. sqMRI scores were not significantly associated with some psychological outcomes or these only bordered on significance after accounting for relevant control variables.

CONCLUSION

The laterality of early-life lesions influences the development of verbal-related cognitive functions.

Relationship between brain structure and Cerebral Visual Impairment in children with Cerebral Palsy: A systematic review

BACKGROUND

Cerebral Visual Impairment (CVI) is very common yet often unrecognised visual dysfunction in children with Cerebral Palsy (CP). Magnetic Resonance Imaging (MRI) is the diagnostic tool in the investigation of brain lesions in children with CP and CVI.

AIM

The aim of this systematic review is to evaluate the relationship between brain structure and CVI, as determined by MRI in children with CP.

METHODS AND PROCEDURES

A comprehensive search of 5 database (PubMed, EMBASE, SCOPUS, CINAHL and Cochrane Database) was undertaken up until June 2019. The PRISMA checklist was then utilised to report on the process of selecting eligible papers. A total of 30 observational studies met the full inclusion criteria. Further, STROBE checklist was employed to report on the observational studies.

OUTCOMES AND RESULTS

Periventricular leucomalacia on MRI was found to have a strong association with CVI in all 30 studies. Only 13 (43 %) studies described dorsal and/ ventral stream dysfunction. There was ambiguity in the definition of CVI.

CONCLUSIONS AND IMPLICATIONS

The overall level of evidence correlating different patterns of CVI and CP (based on GMFCS, motor type and distribution) and MRI was low. Further studies utilising advances in MRI are needed to understand brain reorganisation and patterns of CVI and suggest rehabilitation therapy inclusive of vision.

Inhibitory control and temporal perception in cerebral palsy

Prepotent response inhibition and temporal perception abilities were explored in a sample of individuals with cerebral palsy relative to typically developing peers. The extent to which inhibitory control difficulties might affect temporal processing was also investigated. For this purpose, two inhibitory control tasks and two duration estimation tasks were given to the groups of cerebral palsy and typically developing children. Results showed inhibition and temporal perception problems in the group with cerebral palsy. A relationship was found between inhibition and temporal estimation performances, which indicates that inhibitory control contributes, at least partially, to acquisition of the temporal processing ability.

A Comparison of Developmental Outcomes of Adolescent Neonatal Intensive Care Unit Survivors Born with a Congenital Heart Defect or Born Preterm

OBJECTIVE

To compare cognitive, motor, behavioral, and functional outcomes of adolescents born with a congenital heart defect (CHD) and adolescents born preterm.

STUDY DESIGN

Adolescents (11-19 years old) born with a CHD requiring open-heart surgery during infancy (n = 80) or born preterm ≤29 weeks of gestational age (n = 128) between 1991 and 1999 underwent a cross-sectional evaluation of cognitive (Leiter International Performance Scale-Revised), motor (Movement Assessment Battery for Children-II), behavioral (Strengths and Difficulties Questionnaire), and functional (Vineland Adaptive Behavior Scale-II) outcomes. Independent samples t tests and Pearson χ² or Fisher exact tests were used to compare mean scores and proportions of impairment, respectively, between groups.

RESULTS

Adolescents born with a CHD and adolescents born preterm had similar cognitive, motor, behavioral, and functional outcomes. Cognitive deficits were detected in 14.3% of adolescents born with a CHD and 11.8% of adolescents born preterm. Motor difficulties were detected in 43.5% of adolescents born with a CHD and 50% of adolescents born preterm. Behavioral problems were found in 23.7% of adolescents in the CHD group and 22.9% in the preterm group. Functional limitations were detected in 12% of adolescents born with a CHD and 7.3% of adolescents born preterm.

CONCLUSIONS

Adolescents born with a CHD or born preterm have similar profiles of developmental deficits. These findings highlight the importance of providing long-term surveillance to both populations and guide the provision of appropriate educational and rehabilitation services to better ameliorate long-term developmental difficulties.

Self-reported Chronic Pain in Young Adults With a Low Birth Weight

OBJECTIVE

To investigate self-reported pain in young adults with a low birth weight.

MATERIALS AND METHODS

This study was a part of a long-term follow-up study of preterm very low birth weight (VLBW; birth weight ≤1500 g), term small for gestational age (SGA; birth weight <10th percentile adjusted for sex and parity), and control young adults born during 1986 to 1988. Of the 300 individuals invited, 216 (62 VLBW, 67 term SGA, and 87 controls) completed a pain questionnaire. Of these, 151 (70%) had answered a pain severity question at 19 years. Chronic pain was defined as pain lasting for >6 months and being moderate, severe, or very severe during the past 4 weeks.

RESULTS

The prevalence of chronic pain at 26 years was 16% in the VLBW group, 21% in the term SGA group, and 7% in the control group. The VLBW and the term SGA groups had higher odds ratios for chronic pain (crude OR, 2.6; 95% CI, 0.9-7.6 for the VLBW group and crude OR, 3.6; 95% CI, 1.3-9.9 for the term SGA group vs. controls). The main results remained after adjusting for potential confounding factors. Some attenuation was observed when adjusting for anxiety and depressive problems. Moderate to very severe pain increased from 16% to 41% in the term SGA group from 19 to 26 years, whereas less changes were seen in the VLBW and the control groups.

DISCUSSION

Results of our study imply that pain should be in focus when conducting long-term follow-up programs of individuals with a low birth weight.

Very low birth weight is associated with brain structure abnormalities and cognitive function impairments: A systematic review

Very low birth weight (VLBW) children are at risk of structural brain abnormalities and neurocognitive deficits. Since survival rate of the very low birth weight infants has increased over the past decade, a better understanding of the long-term neurocognitive outcomes is needed. The present systematic review investigated the association between VLBW and cognitive function as well as brain structure. PubMed/Medline, Google Scholar, Scopus and Web of Science databases were searched up from January 2000 to January 2015. The study was restricted to the articles that were about VLBW and its association with cognitive function and brain structure. The initial search yielded 721 articles. There were 44 studies eligible for inclusion after applying the exclusion criteria: 24 follow-up, 14 cohort, and 6 longitudinal studies. Based on this systematic review, we suggest that VLBW is positively related to several cognitive problems and brain structure abnormalities. These findings provide evidence about the importance of early assessment of cognitive development and brain structure to identify at-risk children and provide their specific requirements as early as possible.

White matter integrity in dyskinetic cerebral palsy: Relationship with intelligence quotient and executive function

BACKGROUND

Dyskinetic cerebral palsy (CP) is one of the most disabling motor types of CP and has been classically associated with injury to the basal ganglia and thalamus. Although cognitive dysfunction is common in CP, there is a paucity of published quantitative analyses investigating the relationship between white matter (WM) microstructure and cognition in this CP type.

AIMS

This study aims (1) to compare brain WM microstructure between people with dyskinetic CP and healthy controls, (2) to identify brain regions where WM microstructure is related to intelligence and (3) to identify brain regions where WM microstructure is related to executive function in people with dyskinetic CP and (4) to identify brain regions where the correlations are different between controls and people with CP in IQ and executive functions.

PATIENTS AND METHODS

Thirty-three participants with dyskinetic CP (mean ± SD age: 24.42 ± 12.61, 15 female) were age and sex matched with 33 controls. Participants underwent a comprehensive neuropsychological battery to assess intelligence quotient (IQ) and four executive function domains (attentional control, cognitive flexibility, goal setting and information processing). Diffusion weighted MRI scans were acquired at 3T. Voxel-based whole brain groupwise analyses were used to compare fractional anisotropy (FA) and of the CP group to the matched controls using a general lineal model. Further general linear models were used to identify regions where white matter FA correlated with IQ and each of the executive function domains.

RESULTS

White matter FA was significantly reduced in the CP group in all cerebral lobes, predominantly in regions connected with the parietal and to a lesser extent the temporal lobes. There was no significant correlation between IQ or any of the four executive function domains and WM microstructure in the control group. In participants with CP, lower IQ was associated with lower FA in all cerebral lobes, predominantly in locations that also showed reduced FA compared to controls. Attentional control, goal setting and information processing did not correlate with WM microstructure in the CP group. Cognitive flexibility was associated with FA in regions known to contain connections with the frontal lobe (such as the superior longitudinal fasciculus and cingulum) as well as regions not known to contain tracts directly connected with the frontal lobe (such as the posterior corona radiata, posterior thalamic radiation, retrolenticular part of internal capsule, tapetum, body and splenium of corpus callosum).

CONCLUSION

The widespread loss in the integrity of WM tissue is mainly located in the parietal lobe and related to IQ in dyskinetic CP. Unexpectedly, executive functions are only related with WM microstructure in regions containing fronto-cortical and posterior cortico-subcortical pathways, and not being specifically related to the state of fronto-striatal pathways which might be due to brain reorganization. Further studies of this nature may improve our understanding of the neurobiological bases of cognitive impairments after early brain insult.

Relationship of cognitive functions and gross motor abilities in children with spastic diplegic cerebral palsy

Spastic diplegic cerebral palsy can be accompanied by a myriad of symptoms affecting other body systems including cognitive dysfunction. The purpose of this study was to determine whether a relationship exists between cognitive functions in the form of selective attention and figural memory domains with standing and walking motor abilities in children with diplegic cerebral palsy. The research design was a correlational study. Tasks assessing cognitive function and gross motor abilities were carried out with a sample of 50 children. The data demonstrated the presence of correlation between selective attention and figural memory domains of cognitive function with standing, walking running, and jumping subscales of the Gross Motor Function Measure (GMFM) scale at different ages, and this correlation was significant between selective attention domain and gross motor abilities. The outcome measurements of the current study provide original evidence based on the necessity of including cognitive and physical impairments in the examination and evaluation of children with diplegic cerebral palsy in research and clinical settings.

Fetal growth and psychiatric and socioeconomic problems: population-based sibling comparison

BACKGROUND

It is unclear whether associations between fetal growth and psychiatric and socioeconomic problems are consistent with causal mechanisms.

AIMS

To estimate the extent to which associations are a result of unmeasured confounding factors using a sibling-comparison approach.

METHOD

We predicted outcomes from continuously measured birth weight in a Swedish population cohort (n = 3 291 773), while controlling for measured and unmeasured confounding.

RESULTS

In the population, lower birth weight (⩽ 2500 g) increased the risk of all outcomes. Sibling-comparison models indicated that lower birth weight independently predicted increased risk for autism spectrum disorder (hazard ratio for low birth weight = 2.44, 95% CI 1.99-2.97) and attention-deficit hyperactivity disorder. Although attenuated, associations remained for psychotic or bipolar disorder and educational problems. Associations with suicide attempt, substance use problems and social welfare receipt, however, were fully attenuated in sibling comparisons.

CONCLUSIONS

Results suggest that fetal growth, and factors that influence it, contribute to psychiatric and socioeconomic problems.

Brain volumes and cognitive function in very-low-birth-weight (VLBW) young adults

BACKGROUND

Preterm born very-low-birth-weight (VLBW: birth weight ≤1500 g) survivors have increased risk of perinatal brain injury that may cause deviant brain development and later neuroimpairments, including reduced cognitive functioning.

AIMS

In this long-term follow up study of three year-cohorts (birth years 1986-88) of VLBW subjects and term born controls with normal birth weight, the aim was to examine differences in brain volumes at age 20 years. In addition, the relationships between brain volumes and cognitive abilities and perinatal variables were explored.

METHODS

Forty-four VLBW subjects and 60 controls were assessed with cognitive testing (Wechsler Adult Intelligence Scale - WAIS-III) and structural MRI at 1.5 T, using the FreeSurfer 5.1 software for volumetric analysis. A subpopulation had MRI performed also at age 15, and for this group changes in brain volumes with age were examined.

RESULTS

The VLBW subjects had smaller brain volumes, especially of thalamus, globus pallidus and parts of the corpus callosum, and larger lateral ventricles than controls at age 20. However, no significant group differences in longitudinal change from age 15 to 20 were observed. The most immature and smallest VLBW subjects at birth, and those with the highest perinatal morbidity, showed most pronounced volume deviations. Positive associations between several brain volumes and full IQ, as well as three of four IQ indices in the VLBW group, were observed.

CONCLUSION

Reduced volumes of grey and white matter and ventricular dilatation in VLBW young adults may indicate permanent effects on brain development from perinatal brain injury with influence on later cognitive function.

Do children with cerebral palsy benefit from computerized working memory training? Study protocol for a randomized controlled trial

Background

Cerebral palsy (CP) is the most common motor disability in childhood (2 to 3 per 1000 live births), and is frequently accompanied by cognitive impairments and behavioural problems. Children with CP are at increased risk of attention deficit disorder with or without hyperactivity (Attention Deficit Disorder (ADD)/Attention Deficit Hyperactivity Disorder (ADHD)) including working memory deficits. The primary aim of this study is to evaluate if cognitive training may improve working memory in children with CP.

Methods/Designs

The study is an investigator-blinded, randomized controlled trial with a stepped-wedge design that will include 115 schoolchildren with CP. Eligible for participation are children with CP, aged 7 to 15 years, who are able to follow instructions and handle a computer mouse. Exclusion criteria are the presence of photosensitive epilepsy, Gross Motor Function Classification System (GMFCS) level V (most severe CP) (Phys Ther 80: 974-985, 2000) and severe visual or hearing impairments. Following assessment of eligibility and baseline cognitive assessment the participants will be randomized to either cognitive working memory training or treatment-as-usual (‘control group’). The intervention is a computer-based working memory training program consisting of 25 daily sessions to be performed over a 5 to 6-week period at home. A neuropsychological assessment will be performed before and 4 to 6 weeks after completed training. When the latter assessment has been completed in the intervention group, the ‘control group’ will start on the same training program. Both groups will meet for a final neuropsychological assessment six months after completed training by an examiner unaware of group adherence.

Discussion

There is limited evidence for the effect of most interventions in children with CP, and evidence is completely lacking for interventions aiming to improve deficits in cognition, learning and behaviour. The proposed multicenter study, will bring forth comprehensive information about cognitive, neuropsychological, and daily-life functioning in children with CP aged between 7 and 15 years. In addition, the study will be the first to evaluate the effects of an intervention method to improve working memory in children with CP. If successful, computer-based working memory training may represent an efficient and cost-effective intervention for this group of children.

Trial registration

ClinicalTrials.gov Identifier: NCT02119364

Mediators of the association between parental severe mental illness and offspring neurodevelopmental problems

PURPOSE

Parental severe mental illness (SMI) is associated with an increased risk of offspring autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD). We conducted a study to examine the extent to which risk of preterm birth, low birth weight, and small for gestational age mediated this association.

METHODS

We obtained data on offspring born 1992-2001 in Sweden (n = 870,017) through the linkage of multiple population-based registers. We used logistic and Cox regression to assess the associations between parental SMI, adverse pregnancy outcomes, and offspring ASD and ADHD, as well as tested whether adverse pregnancy outcomes served as mediators.

RESULTS

After controlling for measured covariates, maternal and paternal SMI were associated with an increased risk for preterm birth, low birth weight, and gestational age, and for offspring ASD and ADHD. These pregnancy outcomes were also associated with an increased risk of ASD and ADHD. We found that pregnancy outcomes did not mediate the association between parental SMI and offspring ASD and ADHD, as there was no substantial change in magnitude of the risk estimates after controlling for pregnancy outcomes.

CONCLUSIONS

Parental SMI and adverse pregnancy outcomes appear to be independent risk factors for offspring ASD and ADHD.

Ventricular dilatation in ex-prematures: only confined to the occipital region? MRI-based normative standards for 19-year-old ex-prematures without major handicaps

BACKGROUND

Premature birth may be associated with white matter injury later developing with widening of the ventricles. However, population-based data on normal ventricular size by age are sparse, making the evaluation of possible ventricular dilatation difficult.

PURPOSE

To present the linear measurements of the ventricular system, to compare these to subjectively assessed ventricular size, and to examine differences in ventricular size between ex-prematures and controls.

MATERIAL AND METHODS

Eligible survivors (n = 113) from the initial birth cohort (n = 217, born in 1986-1988, birth weight <2000 g) underwent MRI during 2006-2007. One hundred and three were ex-premature and included in the study. The ventricular size was subjectively judged by a pediatric neuroradiologist, and scored as normal, mildly, moderately, or severely dilated. Objective measurements, including width and depth of the frontal and occipital horns, were performed in a blinded fashion, by a pediatric radiologist.

RESULTS

The normative standards for different parts of the ventricular system in ex-premature young adults varied considerably. We found significant associations between the objective measurements and the subjectively classification of ventricular dilatation. Ex-prematures had smaller heads than those born term (control group). After adjustment for head circumference, there were no significant group differences regarding the frontal horns, but the occipital horns were proportionately wider among ex-prematures.

CONCLUSION

Young adults born prematurely, with a birth weight <2000 g, do not have larger lateral ventricles than healthy controls born term, even after correcting for a smaller head size. However, they do have larger occipital horns, confirming previous studies and strengthening our belief of a specific vulnerability of the occipital region.

Neural correlates of developmental coordination disorder

AIM

To review neuroimaging studies in children with developmental coordination disorder (DCD) systematically. Because only a few studies addressed this, we broadened our search and included neuroimaging studies in children with perinatal adversities and motor impairment without cerebral palsy.

METHOD

Two searches were performed in PubMed, PsycINFO, and Web of Science addressing (1) neuroimaging in DCD and (2) neuroimaging in children with perinatal adversities and motor impairment.

RESULTS

Five studies in children with DCD were identified. Four functional magnetic resonance imaging (MRI) studies showed that children with DCD activate multiple brain areas differently than controls. One diffusion tensor imaging study indicated that the internal capsule in children with DCD showed differences. The second search identified seven studies: three showed that white matter abnormalities and severe abnormalities on MRI were related to motor impairment; four were unable to demonstrate similar relationships.

INTERPRETATION

Data on neuroimaging in DCD are scarce; data available suggest that multiple brain areas are involved in the neuropathophysiology of DCD. Motor impairment in children with perinatal adversities is related especially to white matter abnormalities and severe abnormalities on MRI. We hypothesize that in some children with DCD the neural substrate mimics that of cerebral palsy. More neuroimaging studies are needed to understand the neural correlates of DCD better.

Cerebral magnetic resonance imaging findings in children born extremely preterm, very preterm, and at term

BACKGROUND

The aim of this study was to compare findings on cerebral MRI scans of infants born extremely preterm (i.e., gestation < 28 weeks, very preterm; gestation 28-31 weeks) and at term.

METHODS

MRI scans obtained in a cohort of 29 extremely preterm children at 11 years, 51 very preterm young adults at 19 years, and respective term-born controls were scored according to presence and degree of MRI pathology.

RESULTS

MRI pathology was found in 76% of the extremely preterm children vs 31% of their controls (odds ratio 4.3; 95% confidence interval, 1.5-137.5) and in 55% of the very preterm group vs 19% of their controls (odds ratio 5.2; 95% confidence interval, 2.5-10.9). The distribution of moderate and severe pathology did not differ among the groups.

CONCLUSIONS

The extremely preterm, very preterm, and term subjects shared the same morphological pathology, revealing no specific preterm MRI pattern, but both premature cohorts had higher frequencies. Differences were mainly limited to mild pathology. Whether MRI lesions were more common in the extremely preterm than in the very preterm group is uncertain as the difference in frequency was similar in the two control groups, suggesting a lack of objective criteria for differentiating mild pathology from normality or that MRI scans normally differ at 11 and 19 years of age.

Limitations on the developing preterm brain: impact of periventricular white matter lesions on brain connectivity and cognition

Brain lesions to the white matter in peritrigonal regions, periventricular leukomalacia, in children who were born prematurely represent an important model for studying limitations on brain development. The lesional pattern is of early origin and bilateral, that constrains the compensatory potential of the brain. We suggest that (i) topography and severity of periventricular lesions may have a long-term predictive value for cognitive and social capabilities in preterm birth survivors; and (ii) periventricular lesions may impact cognitive and social functions by affecting brain connectivity, and thereby, the dissociable neural networks underpinning these functions. A further pathway to explore is the relationship between cerebral palsy and cognitive outcome. Restrictions caused by motor disability may affect active exploration of surrounding and social participation that may in turn differentially impinge on cognitive development and social cognition. As an outline for future research, we underscore sex differences, as the sex of a preterm newborn may shape the mechanisms by which the developing brain is affected.

Brain structure and executive functions in children with cerebral palsy: a systematic review

This systematic review aimed to establish the current knowledge about brain structure and executive function (EF) in children with cerebral palsy (CP). Five databases were searched (up till July 2012). Six articles met the inclusion criteria, all included structural brain imaging though no functional brain imaging. Study quality was assessed using the STROBE checklist. All articles scored between 58.7% and 70.5% for quality (100% is the maximum score). The included studies all reported poorer performance on EF tasks for children with CP compared to children without CP. For the selected EF measures non-significant effect sizes were found for the CP group compared to a semi-control group (children without cognitive deficits but not included in a control group). This could be due to the small sample sizes, group heterogeneity and lack of comparison of the CP group to typically developing children. The included studies did not consider specific brain areas associated with EF performance. To conclude, there is a paucity of brain imaging studies focused on EF in children with CP, especially of studies that include functional brain imaging. Outcomes of the present studies are difficult to compare as each study included different EF measures and cortical abnormality measures.

Outcomes of preterm infants: morbidity replaces mortality

Over the last 50 years in the United States a rising preterm birth rate, a progressive decrease in preterm mortality, and a lowering of the limit of viability have made preterm birth a significant public health problem. Neuromaturation, the functional development of the central nervous system (CNS), is a dynamic process that promotes and shapes CNS structural development. This article reviews preterm outcomes, recognizing that multiple factors influence neuromaturation and lead to a range of neurodevelopmental disabilities, dysfunctions, and altered CNS processing. Ways to protect preterm infants and support their growth and development in and beyond intensive care are examined.

Visual perception in preterm children: what are we currently measuring?

Over the past two decades, cerebral visual impairment has been recognized as a principal deficit in preterm children, and in particular those with cerebral palsy. We review the current knowledge of visual processing deficits in these children, and provide an overview of the tools for assessing cerebral visual impairment. Commercially available instruments are usually directed at evaluating visuospatial skills rather than detecting object recognition difficulties. Particularly in children aged 3 years or younger and in children with multiple handicaps, cerebral visual impairment is difficult to diagnose. This difficulty may be attributable to limitations specific to the instrument, such as a test that is inappropriate for age, or to child-specific limitations such as motor impairment or speech delay. We therefore include an overview of relevant neuroimaging findings reported in these children, focusing on the most recent imaging modalities. Novel techniques such as diffusion tensor imaging may provide sensitive markers of cerebral visual impairment in situations where clinical diagnosis is difficult, and such approaches may allow for early intervention.

Neonatal white matter abnormalities predict global executive function impairment in children born very preterm

Using prospective longitudinal data from 110 very preterm and 113 full term children, this article describes the executive functioning abilities of very preterm children at age 4, and examines relations between the extent of white matter abnormality on neonatal magnetic resonance imaging (MRI) and later executive function outcomes. Very preterm children performed less well than full term children on measures of planning ability, cognitive flexibility, selective attention, and inhibitory control. Executive impairments at age 4 were confined to preterm children with mild or moderate-severe white matter abnormalities on MRI. Findings support the importance of cerebral white matter integrity for later executive function.

Total brain white matter is a major determinant of IQ in adolescents born preterm

OBJECTIVE

In preterm infants, white matter (WM) abnormalities detected on magnetic resonance imaging (MRI) at term-age are associated with early developmental delay. We set out to study this association in adolescents born pre-term, by examining intellectual outcome in relation to markers of brain injury, focusing on the effects of WM reduction.

METHODS

Seventy-nine participants were recruited and assessed at a mean age of 16 years: 49 adolescents born preterm (<32 weeks' gestation) with a wide spectrum of brain injuries (including 22 with no identifiable brain injury at birth) and 30 term-born controls. Data collected included: brain MRI scans, full-scale intelligence quotient (IQ) scores, educational attainments, and behavioral scores. Measures of WM reduction included total volume, cross-sectional area of the corpus callosum (CC), and ventricular dilatation. Cerebellar volumes and neuroradiological ratings were also included.

RESULTS

WM volume and IQ were reduced in the preterm groups (both with and without brain injury). Total WM volume and CC area jointly explained 70% of IQ variance in the adolescents born preterm, irrespective of the presence or severity of brain abnormalities detected at birth or on follow-up MRI. This relationship was not seen in controls. Importantly, correlations were also found with real-world measures of academic achievement and behavioral difficulties.

INTERPRETATION

Preterm birth has a long-term effect on cognition, behavior, and future academic success primarily as a consequence of global brain WM reduction. This emphasizes the need for early therapeutic efforts to prevent WM injury and promote or optimize its development in preterm neonates.

Structural correlates of preterm birth in the adolescent brain

OBJECTIVE

The Stockholm Neonatal Project involves a prospective, cross-sectional, population-based, cohort monitored for 12 to 17 years after birth; it was started with the aim of investigating the long-term structural correlates of preterm birth and comparing findings with reports on similar cohorts.

METHODS

High-resolution anatomic and diffusion tensor imaging data measuring diffusion in 30 directions were collected by using a 1.5-T MRI scanner. A total of 143 adolescents (12.18-17.7 years of age) participated in the study, including 74 formerly preterm infants with birth weights of <or=1500 g (range: 645-1486 g) and 69 term control subjects. The 2 groups were well matched with respect to demographic and socioeconomic data. The anatomic MRI data were used for calculation of total brain volumes and voxelwise comparison of gray matter (GM) volumes. The diffusion tensor imaging data were used for voxelwise comparison of white matter (WM) microstructural integrity.

RESULTS

The formerly preterm individuals possessed 8.8% smaller GM volume and 9.4% smaller WM volume. The GM and WM volumes of individuals depended on gestational age and birth weight. The reduction in GM could be attributed bilaterally to the temporal lobes, central, prefrontal, orbitofrontal, and parietal cortices, caudate nuclei, hippocampi, and thalami. Lower fractional anisotropy was observed in the posterior corpus callosum, fornix, and external capsules.

CONCLUSIONS

Although preterm birth was found to be a risk factor regarding long-term structural brain development, the outcome was milder than in previous reports. This may be attributable to differences in social structure and neonatal care practices.

Combining clinical assessment scores and in vivo MR spectroscopy neurometabolites in very low birth weight adolescents

OBJECTIVE

Very low birth weight (VLBW) survivors are at increased risk of neurological impairments that may persist into adolescence and adulthood. The aims of this study were to identify the most important clinical assessments that characterize differences between VLBW and control adolescents, and to look at the relationship between clinical assessments and the metabolites in in vivo MR spectra.

METHODS

At 14-15 years of age, 54 VLBW survivors and 64 term controls were examined clinically. Several neuropsychological and motor assessments were performed. The magnetic resonance (MR) brain spectra were acquired from volumes localized in the left frontal lobe and contained mainly white matter.

RESULTS

Probabilistic neural networks and support vector machines demonstrated that clinical assessments rendered a possibility of the classification of VLBW versus control adolescents. The most important clinical assessments in this classification were visual-motor integration, motor coordination, stroop test, full scale IQ, and grooved pegboard. Through the use of outer product analysis-partial least squares discriminant analysis on a subset of adolescents (n=36), the clinical assessments found to most strongly correlate with the spectral data were the global assessment scale, Wisconsin card sorting test, full scale IQ, grooved pegboard test, and motor coordination test. Clinical assessments that relate to spectral data may be especially dependent on an intact microstructure in frontal white matter.