Hemisphere In Children Research Articles

Electroclinical Features of Infantile Epileptic Spasms Syndrome.

Epileptic spasms are a unique, age-dependent manifestation of epilepsies in infancy and early childhood, commonly occurring as part of infantile epileptic spasms syndrome. Developmental stagnation and subsequent decline may occur in children with epileptic spasms, partly due to the abundant high-amplitude interictal epileptiform and slow wave abnormalities. Early recognition and treatment of epileptic spasms, along with the reversal of the electroencephalography (EEG) findings, are critical for improving outcomes. Recognizing hypsarrhythmia and its variations is key to confirming the diagnosis. The various patterns of hypsarrhythmia are not etiology specific, but could indicate the severity of the disease. Several scoring systems have been proposed to improve the inter-rater reliability of recognizing hypsarrhythmia and to assess EEG progress in response to treatment. Ictal patterns during spasms are brief and composed of slow waves, sharp transients, fast activity, and voltage attenuation, either in isolation or more commonly as a combination of these waveforms. Ictal patterns are commonly diffuse, but may be lateralized to one hemisphere in children with structural etiology. A subset of patients with epileptic spasms has a surgically remediable etiology, with readily identifiable lesions on neuroimaging in most cases. Asymmetry in epileptic spasms, concurrent focal seizures, and asymmetric interictal and ictal EEG findings may be present, but a lack of focality in electrophysiological findings is not uncommon. Intracranial EEG features of epileptic spasms have been described, but the utility of intracranial EEG monitoring in surgical candidates with overt focal epileptogenic lesions on magnetic resonance imaging is questionable, and surgery could be performed using noninvasive data.

Abstract TMP60: Contralesional Brain Regions Mirror the Volume Changes of Their Homologous Counterparts in the Ipsilesional Hemisphere in Children During the First Year After Unilateral Intracerebral Hemorrhage

Introduction: Structural changes following intracerebral hemorrhage (ICH) caused by ruptured brain vascular malformations (VMs) remain poorly understood. We conducted a longitudinal study to examine changes across ipsilesional and contralesional hemispheres after unilateral ICH, mainly in the temporoparietal area. Methods: Brain MRI was acquired in 8 patients aged 8-18 years ( Mean =15.13, SD =3.18) at presentation of ICH prior to treatment (baseline/Session 1) and repeated at 6 months (Session 2) and 12 months (Session 3) post-treatment. Using FreeSurfer 7.4.0, T1 and T2 FLAIR MR images were segmented into cortical and subcortical regions, with gray matter (GM) parcellated based on the DKT atlas. SynthSeg refined lesion extraction for more precise measurements of brain volume. Volume changes were quantified as percent change from baseline with signed values denoting increase or decrease. Pearson correlation and permutation testing ( n =5000) evaluated associations of homologous versus non-homologous regions. Results: There were significant correlations between the volume changes of homologous GM regions, for both Session 2 ( R =0.57, p <0.001) and Session 3 ( R =0.50, p <0.001), and of homologous GM in hemispheric lobes (Session 2: R =0.69, p <0.001; Session 3: R =0.67, p <0.001). Permutation tests confirmed that correlations of volume changes were greater for homologous than non-homologous regions and lobes for Sessions 2 and 3 ( p <0.001 except Session 3 lobes: p =0.016). Conclusions: We observed structural covariance of volume changes between homologous regions, most pronounced in the first 6 months after unilateral ICH. This indicates network-mediated distant effects of ICH, with atrophy reflected by diaschisis and volume recovery mirrored by positive neuroplasticity of contralateral homologs. Lesion-network mapping with correlation to long-term outcome would elucidate the effects of this long-range neuroplasticity following pediatric ICH.

Sex- and Age-Related Features of the Encephalometric Parameters of the Brain Hemispheres in Children of the Second Childhood Period.

We performed a retrospective analysis of the encephalometric parameters of the brain hemispheres in children aged 8 years (30 boys and 30 girls) and 11 years (30 boys and 30 girls). The variability of the parameters of the brain hemispheres depending on age and sex was studied. In 8-year-old children, sex differences were revealed in a significant number of basic parameters: the length of the right and left hemispheres and the lengths of the left frontal lobe, right parietal lobe, right and left occipital lobes. In 11-year-old children, the sex differences were revealed only in the width of the hemispheres. Interhemispheric asymmetry was found in 8-year-old children. The comparative analysis of the encephalometric parameters of the brain hemispheres in children during the second childhood period showed that the dynamics of their changes in this range is very insignificant.

Age-related changes in the microstructural organization of the human posterior associative cortex from birth to age 12 years

BACKGROUND: Human posterior associative cortex, including its temporoparietal–occipital subarea, is important in cognitive control, verbal activity, sensory stimuli processing, and attention regulation, visuomotor responses, and situational decision making. Despite data suggesting the prolonged formation of these higher mental functions during postnatal ontogeny, the posterior associative cortex has been insufficiently characterized with respect to microstructural transformations in its individual functionally specialized zones during childhood development.
 AIM: This study aimed to examine age-related changes in the cytoarchitecture of functionally differentiated zones of the posterior associative cortex in the temporal and occipital lobes of the cerebral hemispheres from birth to 12 years of age.
 MATERIALS AND METHODS: The study analyzed 73 left cerebral hemispheres of male children from birth to age 12 years who died because of an accident. Computerized morphometry was employed to measure cortical thickness, outer pyramidal plate thickness, and pyramidal neuron profile field area on Nissl-stained paraffin sections of the cortex taken in the temporoparietal–occipital subarea (subareas 37ac, 37a, and 37d) and area 19 of the occipital region. Quantitative data were analyzed at annual intervals.
 RESULTS: The thickness of the posterior associative cortex increased on the lateral surface of the temporal and occipital lobes at the ages of 1, 4, and 7 years; on the inferior medial surface of the temporal lobe at the ages of 1 and 6 years; and on its medial surface at the ages of 1 and 7 years. The layer III thickness in subareas 37ac, 37a, and 37d significantly increased synchronously with the increase in cortical cross-sectional area, and in area 19, it continued from the age of 4 to 7 years after the stabilization of the group-average indicators of cortical thickness in this field. All areas examined were characterized by a two-step growth of cortical thickness, which exceeded the growth rate of layer III thickness in relation to the total cortical cross-section. The size of the pyramidal neurons in subareas 37ac and 37d increased in two stages, whereas those in subarea 37a and area 19 increased in three stages of different durations.
 CONCLUSIONS: Microstructural changes in the posterior associative cortex in children are heterochronic, heterodynamic, and specialized not only in topographically and functionally distinct cortical areas but also in separate cytoarchitectonic fields, subfields, and level of cytoarchitectonic layers and intracortical microstructural components. The most significant morphofunctional transformations are observed during the first year of life and at the ages of 3–4, 6–7, and 10 years.

Alterations in cortical morphometry of the contralesional hemisphere in children, adolescents, and young adults with perinatal stroke

Perinatal stroke causes most hemiparetic cerebral palsy and cognitive dysfunction may co-occur. Compensatory developmental changes in the intact contralesional hemisphere may mediate residual function and represent targets for neuromodulation. We used morphometry to explore cortical thickness, grey matter volume, gyrification, and sulcal depth of the contralesional hemisphere in children, adolescents, and young adults after perinatal stroke and explored associations with motor, attention, and executive function. Participants aged 6–20 years (N = 109, 63% male) with unilateral perinatal stroke underwent T1-weighted imaging. Participants had arterial ischemic stroke (AIS; n = 36), periventricular venous infarction (PVI; n = 37) or were controls (n = 36). Morphometry was performed using the Computational Anatomy Toolbox (CAT12). Group differences and associations with motor and executive function (in a smaller subsample) were assessed. Group comparisons revealed areas of lower cortical thickness in contralesional hemispheres in both AIS and PVI and greater gyrification in AIS compared to controls. Areas of greater grey matter volume and sulcal depth were also seen for AIS. The PVI group showed lower grey matter volume in cingulate cortex and less volume in precuneus relative to controls. No associations were found between morphometry metrics, motor, attention, and executive function. Cortical structure of the intact contralesional hemisphere is altered after perinatal stroke. Alterations in contralesional cortical morphometry shown in perinatal stroke may be associated with different mechanisms of damage or timing of early injury. Further investigations with larger samples are required to more thoroughly explore associations with motor and cognitive function.

Диагностические критерии формирования морфологических изменений головного мозга у детей с перинатальным гипоксическим поражением нервной системы

Objective. To determine the diagnostic criteria of morphological changes in children with perinatal hypoxic brain injury. Patients and Methods. The study included 58 full-term newborns with severe hypoxic brain damages who, according to MRI of brain performed on 2–10 days of life, had low rates of diffusion processes of the white matter of the cerebral hemispheres – diffusion coefficient (Ds) of less than 1.35 × 10–3 mm2/s. Children received treatment in the intensive care unit of the regional perinatal center of Krasnodar Children's Clinical Hospital. Follow-up MRI was performed at the 4th week of life. Observation of children was carried out up to 2 years of age. Results. Denominated destructive changes in the nervous tissue with multicystic encephalomalacia were identified in 23 (40%) newborns (group 1). The range of values of Ds of the white matter of cerebral hemispheres in children of the 1st group was 0.60–1.11 × 10–3 m2/s. In the remaining 35 (60%) children (group 2), hypoxic brain damage was manifested by the expansion of the subarachnoid space, the interhemispheric fissure, and the lateral ventricles. These changes were reflected in a decrease in the volume of brain parenchyma with the persistent neurological deficiency in the future (disorders of psycho-speech development, cerebral palsy, structural epilepsy). The range of values of the Ds of the white matter of the cerebral hemispheres in children of the second group was 1.14–1.35 × 10–3 mm2/s. Conclusions. Using the modern high-tech methods of neuroimaging makes it possible to determine the diagnostic criteria for damaging effects of hypoxia in children with perinatal brain injury and in early stage to identify morphological changes in brain tissue. Key words: hypoxia, brain, children, magnetic resonance imaging, neurological outcome

Microstructural changes in the posterior associative cortex in children during the first year of life

The aim of the study was to study of age-related changes in cytoarchitectonics in functionally different areas of the posterior associative cortex in the temporal and occipital lobes of the cerebral hemispheres in children during the first year of life. Material and methods. The study material included left hemispheres of male children (39 observations) aged from birth to 12 months who died in accidents without brain damage. Using computer morphometry, the thickness of the cortex, the thickness of the external pyramidal layer and the area of the profile field of pyramidal neurons were measured on Nissle stained frontal histological sections of the cortex taken in the temporo-parietaloccipital subfield (subfields 37a, 37a, 37d) and field 19 of the occipital region, which are jointly part of the posterior associative cortex. Quantitative data were analyzed at monthly intervals. Results. The thickness of the posterior associative cortex in infants on the lateral surface of the temporal and occipital lobes increased by 3, 6, and 9 months; on the inferior medial and medial surfaces of the temporal lobe, by 5 and 12 months. Significant increases in the cross section of layer III occurred simultaneously: in subfield 37as by 2 and 6 months, in subfield 37a by 3 and 8 months, in subfield 37d by 2 and 5 months, and in field 19 by 3 and 9 months. All of the studied neocortex zones were characterized by two-stage cortical growth in thickness, as well as a faster rate of increase in the thickness of layer III in relation to the total cortical cross section, relative stability in the size of pyramidal neurons in sublayer III3 from birth to 3 months and their intense increase from 3 to 8-9 months. Conclusion. Microstructural changes in different fields of the posterior associative cortex have significant differences, which are reflected in the age-related dynamics of the thickness of the cortex and associative layer III, as well as the size of the pyramidal neurons. The most significant structural and functional changes in these parameters are noted from 3 to 5 months and from 8 to 9 months, as well as by the end of the first year of life.

The role of reading experience in atypical cortical tracking of speech and speech-in-noise in dyslexia

Dyslexia is a frequent developmental disorder in which reading acquisition is delayed and that is usually associated with difficulties understanding speech in noise. At the neuronal level, children with dyslexia were reported to display abnormal cortical tracking of speech (CTS) at phrasal rate. Here, we aimed to determine if abnormal tracking relates to reduced reading experience, and if it is modulated by the severity of dyslexia or the presence of acoustic noise.We included 26 school-age children with dyslexia, 26 age-matched controls and 26 reading-level matched controls. All were native French speakers. Children's brain activity was recorded with magnetoencephalography while they listened to continuous speech in noiseless and multiple noise conditions. CTS values were compared between groups, conditions and hemispheres, and also within groups, between children with mild and severe dyslexia.Syllabic CTS was significantly reduced in the right superior temporal gyrus in children with dyslexia compared with controls matched for age but not for reading level. Severe dyslexia was characterized by lower rapid automatized naming (RAN) abilities compared with mild dyslexia, and phrasal CTS lateralized to the right hemisphere in children with mild dyslexia and all control groups but not in children with severe dyslexia. Finally, an alteration in phrasal CTS was uncovered in children with dyslexia compared with age-matched controls in babble noise conditions but not in other less challenging listening conditions (non-speech noise or noiseless conditions); no such effect was seen in comparison with reading-level matched controls.Overall, our results confirmed the finding of altered neuronal basis of speech perception in noiseless and babble noise conditions in dyslexia compared with age-matched peers. However, the absence of alteration in comparison with reading-level matched controls demonstrates that such alterations are associated with reduced reading level, suggesting they are merely driven by reduced reading experience rather than a cause of dyslexia. Finally, our result of altered hemispheric lateralization of phrasal CTS in relation with altered RAN abilities in severe dyslexia is in line with a temporal sampling deficit of speech at phrasal rate in dyslexia.

Aberrant somatosensory phase synchronization in children with hemiplegic cerebral palsy

Children with hemiplegic cerebral palsy (HCP) often show disturbances of somatosensation. Despite extensive evidence of somatosensory deficits, neurophysiological alterations associated with somatosensory deficits in children with HCP have not been elucidated. Here, we aim to assess phase synchrony within and between contralateral primary (S1) and secondary (S2) somatosensory areas in children with HCP. Intra-regional and inter-regional phase synchronizations within and between S1 and S2 were estimated from somatosensory evoked fields (SEFs) in response to passive pneumatic stimulation of contralateral upper extremities and recorded with pediatric magnetoencephalography (MEG) in children with HCP and typically developing (TD) children. We found aberrant phase synchronizations within S1 and between S1 and S2 in both hemispheres in children with HCP. Specifically, the less-affected (LA) hemisphere demonstrated diminished phase synchronizations after the stimulus onset up to ~120 ms compared to the more-affected (MA) hemisphere and the dominant hemisphere of TD children, while the MA hemisphere showed enhanced phase synchronizations after ~100 ms compared to the LA hemisphere and the TD dominant hemisphere. Our findings indicate abnormal somatosensory functional connectivity in both hemispheres of children with HCP.

Visualization of immature brain lesions: MR patterns of long-term outcomes. Case reports

The periventricular and deep white matter of the immature brain of premature infants has an increased vulnerability to various, primarily ischemic injuries. The leading mechanism of selective vulnerability of the white matter of the large hemispheres in children with a low gestation period is the lack of formation of adjacent blood circulation zones between the main arteries of the developing brain. Magnetic resonance imaging has a high sensitivity to detect damage to the brain substance, both in the acute period and in the period of long-term outcomes. Periventricular leukomalacia (PVL) is one of the variants of brain damage in premature infants and the most common term in the conclusions of diagnostic doctors (ultrasound, CT, MRI). Considering the pathomorphological criteria, not always detected changes in the white matter of the large hemispheres are PVL. Diffuse (telencephalic) gliosis and diffuse leukomalacia are ordinary and typical variants of damage to the white matter of the large hemispheres in extremely premature infants, with a gestation period of up to 30-32 weeks. In the first variant, atrophic changes predominate with a pronounced decrease in the volume of white matter and a secondary expansion of the lateral ventricles. Diffuse leukomalacia is most often mistaken for PVL, but the localization of the white matter lesion of the large hemispheres is extensive and extends beyond the peri- and paraventricular region. Clinical examples show various variants of primary non-hemorrhagic brain lesions in prematurely born children in the long-term period. The analysis of the revealed changes is carried out, taking into account current data on developing the brain and pathomorphological criteria.

Poor reading is characterized by a more connected network with wrong hubs

Using graph theory, we examined topological organization of the language network in Chinese children with poor reading during an auditory rhyming task and a visual spelling task, compared to reading-matched controls and age-matched controls. First, poor readers (PR) showed reduced clustering coefficient in the left inferior frontal gyrus (IFG) and higher nodal efficiency in the bilateral superior temporal gyri (STG) during the visual task, indicating a less functionally specialized cluster around the left IFG and stronger functional links between bilateral STGs and other regions. Furthermore, PR adopted additional right-hemispheric hubs in both tasks, which may explain increased global efficiency across both tasks and lower normalized characteristic shortest path length in the visual task for the PR. These results underscore deficits in the left IFG during visual word processing and conform previous findings about compensation in the right hemisphere in children with poor reading.

Abstract 54: Bilateral Developmental Alterations in Cortical Morphology in Children With Perinatal Stroke

Perinatal stroke (PS) causes hemiparetic cerebral palsy (CP) and lifelong disability. Compensatory changes in the nonlesioned hemisphere may mediate residual function and represent targets for neuromodulation. Region-based approaches may reveal relationships between cortical thickness of nonlesioned primary motor/sensory cortices and motor function. This study uses surface-based morphometry to explore cortical alterations in the nonlesioned hemisphere in children after perinatal stroke. Children aged 6-19 with MRI-confirmed unilateral perinatal stroke and CP underwent T1-weighted anatomical imaging. Participants were classified as arterial ischemic stroke (AIS; n=36), periventricular venous infarction (PVI; n=38), or typically developing controls (TDC; n=53). Group differences in cortical thickness (distance between grey/white matter boundary and pial surface), grey matter volume, gyrification and sulcal depth and relationships between these morphology metrics and validated measures of motor/executive function were explored. Group comparisons revealed less cortical thickness, greater gyrification, and greater surface area in the nonlesioned hemisphere in both AIS and PVI as compared to TDC. Greater volume and sulcal depth were observed in the nonlesioned hemisphere for AIS. The PVI group showed greater volume in the cingulate cortex and less volume in the precuneus relative to TDC. The AIS group showed more widespread differences than the PVI group in volume and other cortical surface parameters when compared with TDC. Only modest correlations were observed between morphometric changes and clinical function. We suggest that broad differences in structural developmental plasticity occur in the nonlesioned hemisphere after perinatal stroke, particularly the larger lesions seen with AIS, and may represent novel targets for therapeutic neuromodulation.

Специфика межполушарной функциональной асимметрии лобной области у детей 4–7 лет с задержкой психического и речевого развития

This work is an attempt to evaluate the ratio of sustainable potentials in the frontal region of the right and left hemispheres in children of 4–7 years of age with speech dysphasia (SD) and light mental problems of cerebral-organic genesis (LMP). The survey was administered to 30 children (20 boys and 10 girls) aged 4 to 7 years (5,5 ± 1,1 years); 15 children had been diagnosed with General Speech Underdevelopment (GSU) in the 2nd or 3rd degree, and the other 15 children had been diagnosed with both SD and LMP. To confirm the diagnoses all the children were examined by a neurologist and a speech therapist. The data obtained during the neurological examination determined the presence of changes on the brainstem, pyramidal and extrapyramidal levels. In turn, the speech therapist determined the degrees of SD caused by a primary disorder of cortical mechanisms. The dynamics of sustainable potential (SP) of the brain in symmetrical prefrontal leads of the left and right hemispheres, corresponding to the projection of the F9 Brodmann area, was evaluated by means of applying miniature liquid non-polarisable silver chloride electrodes. For children with the 2nd and 3rd degree SD in a state of rest a high level of activity coordination in the frontal areas of the right and left hemispheres was detected, whereas a shift to a functional state entailed a reduction in the level of such coordination. In children with a combination of the SD and the LMP there was no change in the level of activity coordination in the hemispheres during the transition from one functional state to another. A higher level of activity in the right hemisphere was revealed in children with a combination of the SD and the LMP in comparison with children with the 2nd and 3rd degree SD only.

Cortical auditory evoked potentials and hemispheric specialization of speech in individuals with learning disability and healthy controls: A preliminary study

Background: Dichotic listening (DL) technique is a behavioral non-invasive tool which is used in studying hemispheric lateralization. Previous studies using behavioral DL have hypothesized that individuals with learning disabilities (LD) exhibit a lack of cortical specialization for processing speech stimulus. However, there is no event related potential (ERP) evidence, hence the main objective of the study is to explore hemispheric asymmetry using cortical auditory evoked potential (CAEPs) in normal hearing adults and also to compare the same in children with LD and healthy controls. Methods: CAEPs were recorded in 16 normal hearing young adults, eight right-handed children with LD and their age matched controls. Two stop constants (/Pa/ – voiceless, bilabial, stop: /Ta/ - voiceless, alveolar, stop) were chosen for this experiment and presented in each ear and dichotically in two different orders (/pa-ta/, /ta-pa/). ERPs were processed using a standard pipeline, and electrodes readings over the left and right hemispheres were averaged to create left and right regions of interest (ROI). The CAEPs were analyzed for mean amplitude and peak latency of P1-N1-P2 components. Results: The current study results suggest no statistically significant difference between the two stimulus in monaural condition and absence of order effect in dichotic condition. In healthy controls the CAEP latencies were shorter over the left hemisphere in both monaural and dichotic conditions in adults and control children. However, it was very evident that such a difference was lacking in children with LD. Conclusions: Hemispheric asymmetry can be detected using CAEPs for speech stimulus. The measures are consistent and void of stimulus or order effect. Taken together, the findings of current study, both monaural and dichotic condition illustrates the hemispheric differences in processing speech stimuli in normal hearers. Absence of latency differences between hemispheres in children with LD indicate a lack of hemispheric asymmetry.

Cortical auditory evoked potentials and hemispheric specialization of speech in individuals with learning disability and healthy controls: A preliminary study.

Background: Dichotic listening (DL) technique is a behavioral non-invasive tool which is used in studying hemispheric lateralization. Previous studies using behavioral DL have hypothesized that individuals with learning disabilities (LD) exhibit a lack of cortical specialization for processing speech stimulus. However, there is no event related potential (ERP) evidence, hence the main objective of the study is to explore hemispheric asymmetry using cortical auditory evoked potential (CAEPs) in normal hearing adults and also to compare the same in children with LD and healthy controls. Methods: CAEPs were recorded in 16 normal hearing young adults, eight right-handed children with LD and their age matched controls. Two stop constants (/Pa/ - voiceless, bilabial, stop: /Ta/ - voiceless, alveolar, stop) were chosen for this experiment and presented in each ear and dichotically in two different orders (/pa-ta/, /ta-pa/). ERPs were processed using a standard pipeline, and electrodes readings over the left and right hemispheres were averaged to create left and right regions of interest (ROI). The CAEPs were analyzed for mean amplitude and peak latency of P1-N1-P2 components. Results: The current study results suggest no statistically significant difference between the two stimulus in monaural condition and absence of order effect in dichotic condition. In healthy controls the CAEP latencies were shorter over the left hemisphere in both monaural and dichotic conditions in adults and control children. However, it was very evident that such a difference was lacking in children with LD. Conclusions: Hemispheric asymmetry can be detected using CAEPs for speech stimulus. The measures are consistent and void of stimulus or order effect. Taken together, the findings of current study, both monaural and dichotic condition illustrates the hemispheric differences in processing speech stimuli in normal hearers. Absence of latency differences between hemispheres in children with LD indicate a lack of hemispheric asymmetry.

The level of steady potentials of the left and right hemispheres in children with learning disabilities

This chapter reviews a growing body of international research that documents a puzzling pattern of gender differences in health and considers the limitations of current explanations. Such limitations derive from a failure to capture the complexity of men's and women's lives because much of the research focuses either on differences in their social and economic status or biology. We argue that an integrated model is needed to enable researchers to understand more fully the health connections between gendered lives and physiological processes. We elaborate the framework of constrained choice (CC) as one approach to address this conundrum. Constrained choice provides an innovative multilevel model for examining how the social environment differentially shapes men's and women's agency and health-related opportunities and choices. We provide examples of studies in the United States and Qatar that employ the framework and highlight ways in which it can be used more effectively in future research.

Metabolic correlates of cognitive function in children with unilateral Sturge-Weber syndrome: Evidence for regional functional reorganization and crowding.

To evaluate metabolic changes in the ipsi- and contralateral hemisphere in children showing a cognitive profile consistent with early reorganization of cognitive function, we evaluated the regional glucose uptake, interhemispheric metabolic connectivity, and cognitive function in children with unilateral SWS. Interictal 2-deoxy-2[18 F]fluoro-D-glucose (FDG)-PET scans of 27 children with unilateral SWS and mild epilepsy and 27 age-matched control (non-SWS children with epilepsy and normal FDG-PET) were compared using statistical parametric mapping (SPM). Regional FDG-PET abnormalities calculated as SPM(t) scores in the SWS group were correlated with cognitive function (IQ) in left- and right-hemispheric subgroups. Interhemispheric metabolic connectivity between homotopic cortical regions was also calculated. Verbal IQ was substantially (≥10 points difference) higher than non-verbal IQ in 61% of the right- and 71% of the left-hemispheric SWS group. FDG SPM(t) scores in the affected hemisphere showed strong positive correlations with IQ in the left-hemispheric, but not in right-hemispheric SWS group in several frontal, parietal, and temporal cortical regions. Significant positive interhemispheric metabolic connectivity, present in controls, was diminished in the SWS group. In addition, the left-hemispheric SWS group showed inverse metabolic interhemispheric correlations in specific parietal, temporal, and occipital regions. FDG SPM(t) scores in the same regions of the right (unaffected) hemisphere showed inverse correlations with IQ. These findings suggest that left-hemispheric lesions in SWS often result in early reorganization of verbal functions while interfering with ("crowding") their non-verbal cognitive abilities. These cognitive changes are associated with specific metabolic abnormalities in the contralateral hemisphere not directly affected by SWS.

Cortical Processing of Level Cues for Spatial Hearing is Impaired in Children with Prelingual Deafness Despite Early Bilateral Access to Sound.

Bilateral cochlear implantation aims to restore binaural hearing, important for spatial hearing, to children who are deaf. Improvements over unilateral implant use are attributed largely to the detection of interaural level differences (ILDs) but emerging evidence of impaired sound localization and binaural fusion suggest that these binaural cues are abnormally coded by the auditory system. We used multichannel electroencephalography (EEG) to assess cortical responses to ILDs in two groups: 13 children who received early bilateral cochlear implants (CIs) simultaneously, known to protect the developing auditory cortices from unilaterally driven reorganization, and 15 age matched peers with normal hearing. EEG source analyses indicated a dominance of right auditory cortex in both groups. Expected reductions in activity to ipsilaterally weighted ILDs were evident in the right hemisphere of children with normal hearing. By contrast, cortical activity in children with CIs showed: (1) limited ILD sensitivity in either cortical hemisphere, (2) limited correlation with reliable behavioral right-left lateralization of ILDs (in 10/12 CI users), and (3) deficits in parieto-occipital areas and the cerebellum. Thus, expected cortical ILD coding develops with normal hearing but is affected by developmental deafness despite early and simultaneous bilateral implantation. Findings suggest that impoverished fidelity of ILDs in independently functioning CIs may be impeding development of cortical ILD sensitivity in children who are deaf but do not altogether limit benefits of listening with bilateral CIs. Future efforts to provide consistent/accurate ILDs through auditory prostheses including CIs could improve binaural hearing for children with hearing loss.

An Event-Related Potential Study on the Perception and the Recognition of Face, Facial Features, and Objects in Children With Autism Spectrum Disorders.

The study investigated whether children with autism spectrum disorders (ASD) showed atypical patterns of brain specialization for face processing, whether the response to familiar and unfamiliar faces, facial features, and objects were different from typically developing children. Event-related potentials were recorded in 5- to 8-year-old children (12 children with ASD, 12 typically developing children) using passive viewing paradigm. The fastest P1 latencies to faces and the largest P1 amplitudes to objects were observed in both participant groups. Both groups exhibited larger N170 response to faces and eyes, F(3, 66) = 46.94, p < .0001). However, earlier P1 and N170 latencies were found on left hemisphere in children with ASD, respectively, F(1, 83) = 4.32, p = .04; F(1, 83) = 6.73, p = .01, indicating an atypical face processing pattern. All children showed a significant effect of familiarity for objects and mouths, F(1, 71) = 33.97, p < .0001; F(1, 71 = 15.94, p = .0002. Children with ASD revealed smaller negative central to faces relative to typically developing children. Face processing abnormalities revealed in children with ASD very likely exist.

Postoperative axonal changes in the contralateral hemisphere in children with medically refractory epilepsy: A longitudinal diffusion tensor imaging connectome analysis

To determine brain plasticity changes due to resective epilepsy surgery in children, we performed a longitudinal connectome analysis on the pattern of axonal connectivity in the contralateral hemisphere. Pre- and postoperative diffusion tensor imaging (DTI) data were acquired from 35 children with intractable focal epilepsy. A total of 54 brain regions of interest (ROIs) were generated in the hemisphere contralateral to the resection. Within a 54×54 connectivity matrix, a pairwise connectivity score was calculated for each connection between two ROIs, based on the DTI fiber streamline number in each connection. A permuted Spearman's ρ-rank analysis was used to identify specific inter-regional connections showing a significant association between the postoperative change of connectivity score and clinical variables. Nineteen connections in the contralateral hemisphere showed postoperative increases in the strength of connectivity. Postoperative increase in connectivity between insular-inferior frontal operculum regions as well as that between superior frontal orbital and mid frontal orbital regions were both significantly associated with a larger surgical resection volume (ρ>+0.40) and a younger patient age (ρ>-0.34). These increases were more robust in patients with frontal resection and in those achieving seizure freedom. Neuropsychological evaluation on subsets of patients revealed that such increases in connectivity were associated with preserved or improved cognitive functions such as visual memory and planning. Resective epilepsy surgery may lead to increased contralateral axonal connectivity in children with focal epilepsy. Our data lead to a hypothesis that such increased connectivity may be an imaging marker of postoperative brain plasticity to compensate for cognitive function. Hum Brain Mapp 37:3946-3956, 2016. © 2016 Wiley Periodicals, Inc.