Speech and oromotor outcome in adolescents born preterm: relationship to motor tract integrity

Noise phenomena in distress cries of term and very preterm infants at term-equivalent age

BACKGROUND AND AIM

To examine whether the noise components in distress cries of term infants differed from very preterm infants whose cries were collected at a comparable "corrected" gestational age.

METHODS

Distress cries were collected from 20 term and 20 preterm infants. The cries were acoustically examined for the occurrence of aperiodic phonatory behavior within and across moments of crying.

RESULTS

The findings indicated no significant differences between term and preterm infants at term age in the occurrence of noise.

CONCLUSIONS

Distress cries of both term and term-equivalent preterm infants appear to contain high instances of phonatory noise. The high arousal associated with distress crying and associated increase in subglottal pressure appeared to influence both term and term-equivalent preterm infants similarly.

White matter microstructural plasticity associated with educational intervention in reading disability

Children's reading progress typically slows during extended breaks in formal education, such as summer vacations. This stagnation can be especially concerning for children with reading difficulties or disabilities, such as dyslexia, because of the potential to exacerbate the skills gap between them and their peers. Reading interventions can prevent skill loss and even lead to appreciable gains in reading ability during the summer. Longitudinal studies relating intervention response to brain changes can reveal educationally relevant insights into rapid learning-driven brain plasticity. The current work focused on reading outcomes and white matter connections, which enable communication among the brain regions required for proficient reading. We collected reading scores and diffusion-weighted images at the beginning and end of summer for 41 children with reading difficulties who had completed either 1st or 2nd grade. Children were randomly assigned to either receive an intensive reading intervention (n = 26; Seeing Stars from Lindamood-Bell which emphasizes orthographic fluency) or be deferred to a wait-list group (n = 15), enabling us to analyze how white matter properties varied across a wide spectrum of skill development and regression trajectories. On average, the intervention group had larger gains in reading compared to the non-intervention group, who declined in reading scores. Improvements on a proximal measure of orthographic processing (but not other more distal reading measures) were associated with decreases in mean diffusivity within core reading brain circuitry (left arcuate fasciculus and left inferior longitudinal fasciculus) and increases in fractional anisotropy in the left corticospinal tract. Our findings suggest that responses to intensive reading instruction are related predominantly to white matter plasticity in tracts most associated with reading.

Use of non-invasive transcutaneous auricular vagus nerve stimulation: neurodevelopmental and sensory follow-up

Objective

To assess the impact of non-invasive transcutaneous auricular vagal nerve stimulation (taVNS) paired with oral feeding on long-term neurodevelopmental and sensory outcomes.

Method

We tested 21 of 35 children who as infants were gastrostomy tube (G-tube) candidates and participated in the novel, open-label trial of taVNS paired with oral feeding. To evaluate possible effects on development at 18-months after infant taVNS, we performed the Bayley-III (n = 10) and Sensory Profile (SP-2, n = 12) assessments before the COVID pandemic, and Cognitive Adaptive Test (CAT), Clinical Linguistics and Auditory Milestone (CLAMS), Ages and Stages Questionnaire (ASQ), and Peabody Developmental Motor Scales-2 gross motor tests as possible during and after the pandemic. We compared outcomes for infants who attained full oral feeds during taVNS ('responders') or received G-tubes ('non-responders').

Results

At a mean of 19-months, taVNS 'responders' showed significantly better general sensory processing on the SP-2 than 'non-responders'. There were no differences in other test scores, which were similar to published outcomes for infants who required G-tubes.

Conclusion

This is the first report of neurodevelopmental follow-up in infants who received taVNS-paired feeding. They had similar developmental outcomes as historical control infants failing oral feeds who received G-tubes. Our data suggests that infants who attained full oral feeds had better sensory processing.

Speech sound production, speech intelligibility, and oral-motor outcomes of preterm children: Are they different from full term children?

We studied the speech sound abilities of preterm (PT) children. Thirty-one PT and twenty-nine full term (FT) children were recruited. Speech abilities were assessed in single word, story retelling, oral-motor, and intelligibility. PT group had poorer outcomes (Mean = 25.77, SD = 17.19) than FT ones (Mean = 5.9, SD = 4.97) for single word (p < 0.001). They obtained poorer results (Mean = 9.65, SD = 7.85) than FT peers (Mean = 2.95, SD = 3.34) in story retelling (p = 0.002) and intelligibility (Man-Whitney U = 89.50, p = 0.02). They obtained lower values for diadochokesis/patuku/(p < 0.001), isolated (p = 0.001), and sequenced movements (p = 0.02) but not for diadochokesis/patukejk/(p = 0.12). Significant values of correlation were found among single word scores with birth weight (r = -.54, p < .001) and gestational age (r = -0.67, p < .001) and story retelling scores with birth weight (r = -0.40, p = .013) and gestational age (r = -0.64, p < .001). The associations of single word score and maternal (r = -0.02, p = .85) and paternal education (r = -0.10, p = .41) were not significant. No significant relationships were obtained between story retelling score and maternal (r = 0.16, p = .34) and paternal education (r = 0.09, p = .59). The significant values were obtained for associations of intelligibility with isolated (r = 0.54, p = .001), sequenced movements (r = 0.59, p < .001), and diadochokesis/patukejk/(r = 0.39, p = .016) but not significant for intelligibility and diadochokesis/patuku/(r = 0.25, p = .13). Findings implied that speech abilities are weaker in PT children.

Structural and functional brain connectivity in moderate-late preterm infants with low-grade intraventricular hemorrhage

PURPOSE

Brain functional connectivity (FC) changes and microstructural abnormalities are reported in infants born moderate and late preterm (MLPT). We evaluated the effect of low-grade (grades I, II) intraventricular hemorrhage (IVH) in MLPT babies on brain structural connectivity (SC) and FC.

METHODS

Babies born MLPT between January 2014 and May 2017 underwent brain ultrasound (US) at 72 h and 7 days after birth, and MRI at around term equivalent. The MRI protocol comprised T1- and T2-weighted sequences, diffusion tensor imaging (DTI), and resting-state functional MRI (fMRI). SC and FC were assessed using graph analysis.

RESULTS

Of 350 MLPT neonates, 15 showed low-grade IVH on US at 72 h, for which brain MRI was available in 10. These 10 infants, with mean gestational age (GA) 34.0 ± 0.8 weeks, comprised the study group, and 10 MLPT infants of mean GA 33.9 ± 1.1 weeks, with no abnormalities on brain US and MRI, were control subjects. All study subjects presented modularity, small world topology, and rich club organization for both SC and FC. The patients with low-grade IVH had lower FC rich club coefficient and lower SC betweenness centrality in the left frontoparietal operculum, and lower SC rich club coefficient in the right superior orbitofrontal cortex than the control subjects.

CONCLUSIONS

Topological and functional properties of mature brain connectivity are present in MLPT infants. IVH in these infants was associated with structural and functional abnormalities in the left frontoparietal operculum and right orbitofrontal cortex, regions related to language and cognition.

Age-related changes in oral motor-control strategies during unpredictable load demands in humans

To investigate age-related changes in oral motor strategies in response to unpredictable load demands. Sixty-five healthy children (aged 3-17 yr) were divided into five age-groups based on their dental eruption stages and compared with a group of healthy adults (aged 18-35 yr). Each participant was asked to perform a standardized motor control task involving 'pulling' and 'holding' a force transducer with the anterior teeth. Different loads were attached to the force transducer in an unpredictable manner. The temporal force profile was divided into two time-segments (an initial segment and a later segment). The peak force and peak force rate during the initial time-segment, and the holding force and intra-trial variability (coefficient of variation) during the later time-segment, were measured. The results showed no differences in the peak force, peak force rate, holding force, and force variability in children compared with adults. However, the trends in the data evaluated using a segmented regression analysis showed that a breakpoint (abrupt change) consistently occurred in the late-mixed dentition group (age 9-11 yr) for most of the outcome variables. The results indicate that while the motor control strategies in children appear to be similar to those in adults, there is a shift in the oral motor developmental trend during the late-mixed dentition stage.

Communication in children born very preterm: a prospective cohort study

AIM

To compare language, speech, and voice of children born preterm and at term, and determine relevant predictors of outcome.

METHOD

Three hundred infants (150 males, 150 females; 149 born at <30wks' gestation, 151 term-born) were prospectively recruited at birth from the Royal Women's Hospital. We administered the Preschool Language Scales, Fifth Edition, Diagnostic Evaluation of Articulation and Phonology, Grade Roughness Breathiness Asthenia Strain Scale, and Pediatric Voice Handicap Index at 3 years, and compared groups. We examined hypothesized predictors in children born preterm: gestational age at birth, birthweight, sex, chronic lung disease, high social risk, multilingualism, neurodevelopmental diagnosis, and oromotor feeding.

RESULTS

Children born preterm had poorer language than children born at term (coefficient -5.43). Speech and voice were similar between groups (coefficients -0.70 to 1.63). Chronic lung disease predicted voice (coefficient 6.05); male sex (coefficients 4.54-6.18), high social risk (coefficient -6.02 to -9.30), and neurodevelopmental diagnosis (coefficients -16.42 to -20.61) predicted language.

INTERPRETATION

Children born before 30 weeks' gestation had poorer language than children born at term. Children born preterm with neurodevelopmental disabilities or high social risk experience poorer language outcomes, and would benefit from enrichment of their language environment.

WHAT THIS PAPER ADDS

Speech and voice outcomes were similar between children born preterm and at term. Male sex, high social risk, and neurodevelopmental diagnosis predicted language outcomes.

Corticobulbar Tract Injury, Oromotor Impairment and Language Plasticity in Adolescents Born Preterm

Children born preterm are at risk of impairments in oromotor control, with implications for early feeding and speech development. In this study, we aimed to identify (a) neuroanatomical markers of persistent oromotor deficits using diffusion-weighted imaging (DWI) tractography and (b) evidence of compensatory neuroplasticity using functional MRI (fMRI) during a language production task. In a cross-sectional study of 36 adolescents born very preterm (<33 weeks' gestation) we identified persistent difficulties in oromotor control in 31% of cases, but no clinical diagnoses of speech-sound disorder (e.g., dysarthria, dyspraxia). We used DWI-tractography to examine the microstructure (fractional anisotropy, FA) of the corticospinal and corticobulbar tracts. Compared to the unimpaired group, the oromotor-impaired group showed (i) reduced FA within the dorsal portion of the left corticobulbar tract (containing fibres associated with movements of the lips, tongue, and larynx) and (ii) greater recruitment of right hemisphere language regions on fMRI. We conclude that, despite the development of apparently normal everyday speech, early injury to the corticobulbar tract leads to persistent subclinical problems with voluntary control of the face, lips, jaw, and tongue. Furthermore, we speculate that early speech problems may be ameliorated by cerebral plasticity - in particular, recruitment of right hemisphere language areas.

Is it possible to safely prevent late preterm and early term births?

Late preterm and early term birth is associated with adverse short- and long-term consequences, particularly for neurodevelopment. A clear reduction in these births can be achieved by avoidance of non-medically indicated births prior to 39 weeks gestation, as shown following the introduction of prohibitive policies in the USA. However, clinicians and policy-makers must always consider the potential for unintended adverse consequences of such action, such as a potential for an increase in term stillbirth. Finding the balance between optimising long-term neurological outcomes and avoiding rare but devastating term stillbirths is one of the challenges of modern maternity care. In this article we review the current evidence for whether this balance can be found, where early births can be safely prevented, and what remains to be addressed to optimise this balance safely.

Early assessment of lateralization and sex influences on the microstructure of the white matter corticospinal tract in healthy term neonates

We assessed the sex and the lateralization differences in the corticospinal tract (CST) during the early postnatal period. Twenty-five healthy term neonates (13 girls, aged 39.2 ± 1.2 weeks, and 12 boys aged 38.6 ± 3.0 weeks) underwent Diffusion Tensor Imaging (DTI). Fiber tracking was performed to extract bilaterally the CST pathways and to quantify the parallel (E₁ ) and perpendicular (E₂₃ ) diffusions, the apparent diffusion coefficient (ADC), and fractional anisotropy (FA). The measurements were performed on the entire CST fibers and on four segments: base of the pons (CST-Po), cerebral peduncles (CST-CP), posterior limb of the internal capsule (CST-PLIC), and corona-radiata (CST-CR). Significantly higher E₁ , lower E_23, and higher FA in the right compared to the left were noted in the CST-PLIC of the girls. Significantly lower E₂₃ and lower ADC with higher FA in the right compared to left were observed in the CST-CP of the boys. Moreover, the CST-PLIC of the boys had significantly higher E₁ in the right compared to the left. There was a significant increase in left CST E₁ of boys when compared with girls. Girls had a significantly lower E₁ , lower E₂₃ and, lower ADC in the left CST-CP compared with boys. In addition, girls had a significantly lower E₂₃ and higher FA in the right CST-PLIC compared with boys. Sex differences and lateralization in structure-based segments of the CST were found in healthy term infants during early postnatal period. These findings are vital to understanding motor development of healthy term born neonates to better interpret newborn infants with abnormal neurodevelopment.

White matter microstructure is associated with language in children born very preterm

Very preterm birth is associated with altered white matter microstructure and language difficulties, which may compromise communication, social function and academic achievement, but the relationship between these two factors is unclear. The aim of this study was to explore associations between white matter microstructure and language domains of semantics, grammar and phonological awareness at 7-years of age on a whole-brain level and within the arcuate fasciculus, an important language pathway, in very preterm and term-born children. Language was assessed in 145 very preterm-born (<30 weeks' gestation and/or <1250 g birth weight) and 33 term-born children aged 7 years. Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), mean diffusivity (MD), axon orientation dispersion and axon density were estimated from diffusion magnetic resonance images also obtained at 7 years. The correlation between diffusion values and language was assessed using Tract-Based Spatial Statistics (TBSS). The arcuate fasciculus was delineated using constrained spherical deconvolution tractography and diffusion parameters from this tract were related to language measures using linear regression. While there was evidence for widespread associations between white matter microstructure and language, there was little evidence of differences in these associations between very preterm and term-born groups. TBSS analyses revealed that higher FA and lower AD, RD, and MD in major fibre tracts, including those subserving language, were associated with better semantic, grammar and phonological awareness performance. Higher axon density in widespread fibre tracts was also associated with better semantic performance. The tractography analyses of the arcuate fasciculus showed some evidence for associations between white matter microstructure and language outcomes. White matter microstructural organisation in widespread fibre tracts, including language-relevant pathways, was associated with language performance in whole-brain and tract-based analyses. The associations were similar for very preterm and term-born groups, despite very preterm children performing more poorly across language domains.

Localization of orofacial representation in the corona radiata, internal capsule and cerebral peduncle in Macaca mulatta

Subcortical white matter injury is often accompanied by orofacial motor dysfunction, but little is known about the structural substrates accounting for these common neurological deficits. We studied the trajectory of the corticobulbar projection from the orofacial region of the primary (M1), ventrolateral (LPMCv), supplementary (M2), rostral cingulate (M3) and caudal cingulate (M4) motor regions through the corona radiata (CR), internal capsule (IC) and crus cerebri of the cerebral peduncle (ccCP). In the CR each pathway was segregated. Medial motor area fibers (M2/M3/M4) arched over the caudate and lateral motor area fibers (M1/LPMCv) curved over the putamen. At superior IC levels, the pathways were widespread, involving the anterior limb, genu and posterior limb with the M3 projection located anteriorly, followed posteriorly by projections from M2, LPMCv, M4 and M1, respectively. Inferiorly, all pathways maintained this orientation but shifted posteriorly, with adjacent fiber bundles overlapping minimally. In the ccCP, M3 fibers were located medially and M1 fibers centromedially, with M2, LPMCv, and M4 pathways overlapping in between. Finally, at inferior ccCP levels, all pathways overlapped. Following CR and superior IC lesions, the dispersed pathway distribution may correlate with acute orofacial dysfunction with spared pathways contributing to orofacial motor recovery. In contrast, the gradually commixed nature of pathway representation inferiorly may enhance fiber vulnerability and correlate with severe, prolonged deficits following lower subcortical and midbrain injury. Additionally, in humans these findings may assist in interpreting orofacial movements evoked during deep brain stimulation, and neuroimaging tractography efforts to localize descending orofacial motor pathways.

Neuropredictors of oromotor feeding impairment in 12month-old children

BACKGROUND

Feeding impairment is prevalent in children with neurodevelopmental issues. Neuroimaging and neurobehavioral outcomes at term are predictive of later neuromotor impairment, but it is unknown whether they predict feeding impairment.

AIMS

To determine whether neurobehavior and brain magnetic resonance imaging (MRI) at term predict oromotor feeding at 12 months in preterm and term-born children.

STUDY DESIGN

Prospective cohort study.

SUBJECTS

248 infants (97 born <30 weeks and 151 born at term) recruited at birth.

OUTCOME MEASURES

Neurobehavioral assessments (General Movements (GMA), Hammersmith Neonatal Neurological Examination (HNNE), Neonatal Intensive Care Unit Network Neurobehavioral Scale (NNNS)); and brain MRI were administered at term-equivalent age. Oromotor feeding was assessed at 12 months corrected age using the Schedule for Oral Motor Assessment.

RESULTS

49/227 children had oromotor feeding impairment. Neurobehavior associated with later feeding impairment was: suboptimal NNNS stress (odds ratio [OR] 2.68; 95% confidence interval [CI] 1.20–6.01), non-optimal reflexes (OR 3.33; 95% CI 1.37–8.11) and arousal scales (OR 2.54; 95% CI 1.03–6.27); suboptimal HNNE total (OR 4.69; 95% CI 2.20–10.00), reflexes (OR 2.62; 95% CI 1.06–6.49), and tone scores (OR 3.87; 95% CI 1.45–10.35); and abnormal GMA (OR 2.60; 95% CI 1.21–5.57). Smaller biparietal diameter also predicted feeding impairment (OR 0.88; 95% CI 0.79–0.97). There was little evidence that relationships differed between birth groups.

CONCLUSIONS

Neurobehavior and biparietal diameter at term are associated with oromotor feeding at 12 months. These results may identify children at greatest risk of oromotor feeding impairment.

Neural correlates of language variability in preschool-aged boys with autism spectrum disorder

Children with autism vary widely in their language abilities, yet the neural correlates of this language variability remain unclear, especially early in development. Diffusion tensor imaging (DTI) was used to examine diffusivity measures along the length of 18 major fiber tracts in 104 preschool-aged boys with autism spectrum disorder (ASD). The boys were assigned to subgroups according to their level of language development (Low: no/low language, Middle: small vocabulary, High: large vocabulary and grammar), based on their raw scores on the expressive language (EL) and receptive language (RL) sections of the Mullen Scales of Early Learning (MSEL). Results indicate that the subgroups differed in fractional anisotropy (FA), mean diffusivity (MD), and radial diffusivity (RD) along the inferior longitudinal fasciculus (ILF) in both hemispheres. Moreover, FA correlated significantly with Mullen EL and RL raw scores, but not ADOS severity score, along the left and right ILF. Subgroups also differed in MD (but not FA) along the left superior longitudinal fasiculus and left corticospinal tract, but these differences were not correlated with language scores. These findings suggest that white matter microstructure in the left and right ILF varies in relation to lexical development in young males with ASD. The findings also support the use of raw scores on language-relevant standardized tests for assessing early language-brain relationships. Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Autism Res 2017, 10: 1107-1119. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Early development of structural networks and the impact of prematurity on brain connectivity

Preterm infants are at high risk of neurodevelopmental impairment, which may be due to altered development of brain connectivity. We aimed to (i) assess structural brain development from 25 to 45 weeks gestational age (GA) using graph theoretical approaches and (ii) test the hypothesis that preterm birth results in altered white matter network topology. Sixty-five infants underwent MRI between 25⁺³ and 45⁺⁶ weeks GA. Structural networks were constructed using constrained spherical deconvolution tractography and were weighted by measures of white matter microstructure (fractional anisotropy, neurite density and orientation dispersion index). We observed regional differences in brain maturation, with connections to and from deep grey matter showing most rapid developmental changes during this period. Intra-frontal, frontal to cingulate, frontal to caudate and inter-hemispheric connections matured more slowly. We demonstrated a core of key connections that was not affected by GA at birth. However, local connectivity involving thalamus, cerebellum, superior frontal lobe, cingulate gyrus and short range cortico-cortical connections was related to the degree of prematurity and contributed to altered global topology of the structural brain network. The relative preservation of core connections at the expense of local connections may support more effective use of impaired white matter reserve following preterm birth.

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First characterisation of preterm brain networks weighted by microstructural features.

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Preterm brain is resistant to disruptions in development of core connections.

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Peripheral connections associated with cognition and behaviour are more vulnerable.

Improvement in White Matter Tract Reconstruction with Constrained Spherical Deconvolution and Track Density Mapping in Low Angular Resolution Data: A Pediatric Study and Literature Review

INTRODUCTION

Diffusion-weighted magnetic resonance imaging (DW-MRI) allows noninvasive investigation of brain structure in vivo. Diffusion tensor imaging (DTI) is a frequently used application of DW-MRI that assumes a single main diffusion direction per voxel, and is therefore not well suited for reconstructing crossing fiber tracts. Among the solutions developed to overcome this problem, constrained spherical deconvolution with probabilistic tractography (CSD-PT) has provided superior quality results in clinical settings on adult subjects; however, it requires particular acquisition parameters and long sequences, which may limit clinical usage in the pediatric age group. The aim of this work was to compare the results of DTI with those of track density imaging (TDI) maps and CSD-PT on data from neonates and children, acquired with low angular resolution and low b-value diffusion sequences commonly used in pediatric clinical MRI examinations.

MATERIALS AND METHODS

We analyzed DW-MRI studies of 50 children (eight neonates aged 3-28 days, 20 infants aged 1-8 months, and 22 children aged 2-17 years) acquired on a 1.5 T Philips scanner using 34 gradient directions and a b-value of 1,000 s/mm². Other sequence parameters included 60 axial slices; acquisition matrix, 128 × 128; average scan time, 5:34 min; voxel size, 1.75 mm × 1.75 mm × 2 mm; one b = 0 image. For each subject, we computed principal eigenvector (EV) maps and directionally encoded color TDI maps (DEC-TDI maps) from whole-brain tractograms obtained with CSD-PT; the cerebellar-thalamic, corticopontocerebellar, and corticospinal tracts were reconstructed using both CSD-PT and DTI. Results were compared by two neuroradiologists using a 5-point qualitative score.

RESULTS

The DEC-TDI maps obtained presented higher anatomical detail than EV maps, as assessed by visual inspection. In all subjects, white matter (WM) tracts were successfully reconstructed using both tractography methodologies. The mean qualitative scores of all tracts obtained with CSD-PT were significantly higher than those obtained with DTI (p-value < 0.05 for all comparisons).

CONCLUSION

CSD-PT can be successfully applied to DW-MRI studies acquired at 1.5 T with acquisition parameters adapted for pediatric subjects, thus providing TDI maps with greater anatomical detail. This methodology yields satisfactory results for clinical purposes in the pediatric age group.

Language and hearing outcomes of preterm infants

Multiple factors including degree of prematurity, neonatal morbidities, illness severity, hearing status, gender, language environment in the neonatal intensive care unit and in the home, maternal education level, social and environmental status of the family, and access to early intervention all contribute to the language outcomes of extremely preterm infants with and without hearing loss. Early screening, early diagnosis, and early intervention services by 6 months of age are necessary to optimize the language outcomes of preterm infants with permanent hearing loss. There is increasing evidence of the potential for improved language skills with increasing age of extreme preterm infants and infants with hearing loss.

Brain structural and microstructural alterations associated with cerebral palsy and motor impairments in adolescents born extremely preterm and/or extremely low birthweight

AIM

To elucidate neurobiological changes underlying motor impairments in adolescents born extremely preterm (gestation <28wks) and/or with extremely low birthweight (ELBW, <1000g), our aims were the following: (1) to compare corticospinal tract (CST) microstructure and primary motor cortex (M1) volume, area, and thickness between extremely preterm/ELBW adolescents and a comparison group with normal birthweight (>2499g); (2) to compare CST microstructure and M1 volume, area, and thickness between extremely preterm/ELBW adolescents with cerebral palsy (CP), motor impairment without CP, and no motor impairment; and (3) to investigate associations between CST microstructure and M1 measures.

METHOD

This study used diffusion and structural magnetic resonance imaging to examine the CST and M1 in a geographical cohort of 191 extremely preterm/ELBW adolescents (mean age 18y 2.4mo [SD 9.6mo]; 87 males, 104 females) and 141 adolescents in the comparison group (mean age 18y 1.2mo [SD 9.6mo]; 59 males, 82 females).

RESULTS

Extremely preterm/ELBW adolescents had higher CST axial, radial, and mean diffusivities and lower M1 thickness than the comparison group. Extremely preterm/ELBW adolescents with CP had higher CST diffusivities than non-motor-impaired extremely preterm/ELBW adolescents. CST diffusivities correlated with M1 volume and area.

INTERPRETATION

Extremely preterm/ELBW adolescents have altered CST microstructure, which is associated with CP. Furthermore, the results elucidate how CST and M1 alterations interrelate to potentially influence motor function in extremely preterm/ELBW adolescents.

White matter abnormalities and impaired attention abilities in children born very preterm

While attention impairments are commonly observed in very preterm (<32weeks' gestational age) children, neuroanatomical correlates of these difficulties are unclear. We aimed to determine whether the microstructural organization of key white matter tracts thought to be involved in attention (cingulum bundle, superior longitudinal fasciculi, reticular activating system, and corpus callosum) were altered in very preterm children compared with term-born controls. We also aimed to determine whether alterations in microstructural organization of these tracts were associated with attention functioning in very preterm children. One hundred and forty-nine very preterm children and 36 term-born controls underwent neuroimaging and assessment of their attention abilities at 7years. Constrained spherical deconvolution and probabilistic tractography was used to identify the key white matter tracts. Altered microstructural organization and reduced tract volume within reticular activating system and corpus callosum were found in the very preterm group compared with the control group. Diffusion and volume changes in the cingulum bundle, superior longitudinal fasciculi, reticular activating system, and corpus callosum were related to variations in attention functioning in the very preterm children. These findings emphasize that white matter tract integrity is associated with later attentional abilities in very preterm children.

Speech and language outcomes of very preterm infants

Speech and language impairments of both simple and complex language functions are common among former preterm infants. Risk factors include lower gestational age and increasing illness severity including severe brain injury. Even in the absence of brain injury, however, altered brain maturation and vulnerability imposed by premature entrance to the extrauterine environment is associated with brain structural and microstructural changes. These alterations are associated with language impairments with lasting effects in childhood and adolescence and increased needs for speech therapy and education supports. Studies are needed to investigate language interventions which begin in the neonatal intensive care unit.

Communication ability in cerebral palsy: a study from the CP register of western Sweden

BACKGROUND

Communication is often impaired in cerebral palsy (CP). Tools are needed to describe this complex function, in order to provide effective support.

AIM

To study communication ability and the relationship between the Communication Function Classification System (CFCS) and CP subtype, gross motor function, manual ability, cognitive function and neuroimaging findings in the CP register of western Sweden.

METHODS

Sixty-eight children (29 girls), 14 with unilateral spastic CP, 35 with bilateral spastic CP and 19 with dyskinetic CP, participated. The CFCS, Gross Motor Function Classification System (GMFCS) and Manual Ability Classification System (MACS) levels, cognitive impairment and neuroimaging findings were recorded.

RESULTS

Half the children used speech, 32% used communication boards/books and 16% relied on body movements, eye gaze and sounds. Twenty-eight per cent were at the most functional CFCS level I, 13% at level II, 21% at level III, 10% at level IV and 28% at level V. CFCS levels I-II were found in 71% of children with unilateral spastic CP, 46% in bilateral spastic CP and 11% in dyskinetic CP (p = 0.03). CFCS correlated with the GMFCS, MACS and cognitive function (p < 0.01). Periventricular lesions were associated with speech and more functional CFCS levels, while cortical/subcortical and basal ganglia lesions were associated with the absence of speech and less functional CFCS levels (p < 0.01).

CONCLUSION

Communication function profiles in CP can be derived from the CFCS, which correlates to gross and fine motor and cognitive function. Good communication ability is associated with lesions acquired early, rather than late, in the third trimester.

Long-term neurobiological consequences of early postnatal hCMV-infection in former preterms: a functional MRI study

Early postnatal infection with human cytomegalovirus (hCMV) may contribute to an adverse cognitive outcome in early preterm-born children (PT). We here set out to explore whether long-term neurobiological consequences of such an infection are detectable using fMRI in children and adolescents who were born very preterm and who either did (PThCMV+ ) or did not (PT(hCMV-)) suffer from an early postnatal hCMV-infection, when compared with typically developing healthy control (HC) subjects. Overall, data from 71 children and adolescents could be included, 34 PT (of which 15 were PT(hCMV+) and 19 were PT(hCMV-)) and 37 HC. Using a recently established "dual use" fMRI task, we investigated language and visuospatial functions. There were significant activation differences in the left hippocampus (PT > HC and PT(hCMV+) > HC), and in the right anterior cingulate cortex (PT(hCMV-) > PT(hCMV+)) when performing the language task. Surprisingly, only a small region in the occipital cortex showed a significant activation difference (HC > PT(HCMV-)) when performing the visuospatial task. Targeted analyses revealed differences in gray matter volume, but not density, in several brain regions. Our results suggest that long-term neurobiological consequences of an early postnatal hCMV infection are detectable even in older children and adolescents formerly born very preterm, compatible with a higher effort when performing a cognitive task. This suggests that measures to prevent such an infection are warranted. Furthermore, an interrelation of brain structure and function was detected that may constitute a severe confound when using fMRI to compare structurally differing groups.

Diffusion magnetic resonance imaging in preterm brain injury

INTRODUCTION

White matter injury and abnormal maturation are thought to be major contributors to the neurodevelopmental disabilities observed in children and adolescents who were born preterm. Early detection of abnormal white matter maturation is important in the design of preventive, protective, and rehabilitative strategies for the management of the preterm infant. Diffusion-weighted magnetic resonance imaging (d-MRI) has become a valuable tool in assessing white matter maturation and injury in survivors of preterm birth. In this review, we aim to (1) describe the basic concepts of d-MRI; (2) evaluate the methods that are currently used to analyse d-MRI; (3) discuss neuroimaging correlates of preterm brain injury observed at term corrected age; during infancy, adolescence and in early adulthood; and (4) explore the relationship between d-MRI measures and subsequent neurodevelopmental performance.

METHODS

References for this review were identified through searches of PubMed and Google Scholar before March 2013.

RESULTS

The impact of premature birth on cerebral white matter can be observed from term-equivalent age through to adulthood. Disruptions to white matter development, identified by d-MRI, are related to diminished performance in functional domains including motor performance, cognition and behaviour in early childhood and in later life.

CONCLUSION

d-MRI is an effective tool for investigating preterm white matter injury. With advances in image acquisition and analysis approaches, d-MRI has the potential to be a biomarker of subsequent outcome and to evaluate efficacy of clinical interventions in this population.

Speech-language pathology insights into genetics and neuroscience: beyond surface behaviour

For almost a century, speech-language pathologists (SLPs) have worked at refining communication disorder phenotypes. Yet a hundred years of mastering the characterization of surface behaviours has provided only limited understanding of the neurobiological underpinnings of communication disorder. Arguably, the most momentous aetiological findings in speech-language pathology have been made relatively recently and by cross-disciplinary colleagues in the fields of molecular genetics and neuroimaging. Such findings include discovery of FOXP2, for example, the first gene found to be associated with a primary speech disorder. New gene-brain-behaviour discoveries in communication disorder are occurring on an almost weekly basis and it is challenging for clinical SLPs to engage with, interpret, and keep abreast of this literature. This paper aims to provide a brief overview of genetic and neuroimaging approaches to the study of communication disorders. Further examples of key findings in these fields are presented, with a discussion of the impacts on core SLP practice. Future research directions for further illuminating gene-brain-behaviour relationships in communication disorder are identified.

Interhemispheric temporal lobe connectivity predicts language impairment in adolescents born preterm

Although language difficulties are common in children born prematurely, robust neuroanatomical correlates of these impairments remain to be established. This study investigated whether the greater prevalence of language problems in preterm (versus term-born) children might reflect injury to major intra- or interhemispheric white matter pathways connecting frontal and temporal language regions. To investigate this, we performed a comprehensive assessment of language and academic abilities in a group of adolescents born prematurely, some of whom had evidence of brain injury at birth (n = 50, mean age: 16 years, mean gestational age: 27 weeks) and compared them to a term-born control group (n = 30). Detailed structural magnetic resonance imaging and diffusion-tractography analyses of intrahemispheric and interhemispheric white matter bundles were performed. Analysis of intrahemispheric pathways included the arcuate fasciculus (dorsal language pathway) and uncinate fasciculus/extreme capsule (ventral language pathway). Analysis of interhemispheric pathways (in particular, connections between the temporal lobes) included the two major commissural bundles: the corpus callosum and anterior commissure. We found language impairment in 38% of adolescents born preterm. Language impairment was not related to abnormalities of the arcuate fasciculus (or its subsegments), but was associated with bilateral volume reductions in the ventral language pathway. However, the most significant volume reduction was detected in the posterior corpus callosum (splenium), which contains interhemispheric connections between the occipital, parietal and temporal lobes. Diffusion tractography showed that of the three groups of interhemispheric fibres within the splenium, only those connecting the temporal lobes were reduced. Crucially, we found that language impairment was only detectable if the anterior commissure (a second temporal lobe commissural pathway) was also small. Regression analyses showed that a combination of anatomical measures of temporal interhemispheric connectivity (through the splenium of the corpus callosum and anterior commissure) explained 57% of the variance in language abilities. This supports recent theories emphasizing the importance of interhemispheric connections for language, particularly in the developing brain.

Effect of cerebral hypothermia and asphyxia on the subventricular zone and white matter tracts in preterm fetal sheep

Prolonged, moderate cerebral hypothermia is consistently neuroprotective after experimental hypoxia-ischemia. We have previously shown that hypothermia is also protective after profound asphyxia in the preterm brain. However, there is a concern whether hypothermia could suppress the proliferative response to injury in the white matter or subventricular zone (SVZ). Preterm (0.7 gestation) fetal sheep received complete umbilical cord occlusion for 25 min followed by cerebral hypothermia (extradural temperature reduced from 39.4±0.3 to 29.5±2.6°C) from 90 min to 70h after the end of occlusion or sham cooling. Occlusion-normothermia was associated with no effect on CNPase+ cells, but loss of O4+ oligodendrocytes, induction of cleaved caspase-3, and IB4+ microglia in the gyral and periventricular white matter compared to sham-occlusion (p < 0.05), with a significant increase in KI67+ cells in the periventricular white matter (p < 0.05). Hypothermia was associated with significant protection of O4+ cells, with suppression of IB4+ microglia and KI67+ cells in the periventricular white matter. There was no significant change in astrocytes, microglia, KI67+, or caspase-3+ cells in the SVZ after asphyxia. In conclusion, this study provides strong support for the selective vulnerability of immature oligodendrocytes to a highly relevant insult in the fetal sheep. Although white matter protection with cerebral hypothermia was associated with reduced proliferation in the white matter tracts, it did not impair proliferation in the SVZ.