Publications by authors named "Darren S Kadis"

33 Publications

Extremely preterm children demonstrate hyperconnectivity during verb generation: A multimodal approach.

Neuroimage Clin 2021 Feb 12;30:102589. Epub 2021 Feb 12.

Hospital for Sick Children and University of Toronto are in Toronto, Canada; University of Toronto, Department of Physiology, Canada.

Children born extremely preterm (EPT, <28 weeks gestation) are at risk for delays in development, including language. We use fMRI-constrained magnetoencephalography (MEG) during a verb generation task to assess the extent and functional connectivity (phase locking value, or PLV) of language networks in a large cohort of EPT children and their term comparisons (TC). 73 participants, aged 4 to 6 years, were enrolled (42 TC, 31 EPT). There were no significant group differences in age, sex, race, ethnicity, parental education, or family income. There were significant group differences in expressive language scores (p < 0.05). Language representation was not significantly different between groups on fMRI, with task-specific activation involving bilateral temporal and left inferior frontal cortex. There were group differences in functional connectivity seen in MEG. To identify a possible subnetwork contributing to focal spectral differences in connectivity, we ran Network Based Statistics analyses. For both beta (20-25 Hz) and gamma (61-70 Hz) bands, we observed a subnetwork showing hyperconnectivity in the EPT group (p < 0.05). Network strength was computed for the beta and gamma subnetworks and assessed for correlation with language performance. For the EPT group exclusively, strength of the subnetwork identified in the gamma frequency band was positively correlated with expressive language scores (r = 0.318, p < 0.05). Thus, hyperconnectivity is positively related to language for EPT children and might represent a marker for resiliency in this population.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nicl.2021.102589DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7903004PMC
February 2021

Beta synchrony for expressive language lateralizes to right hemisphere in development.

Sci Rep 2021 Feb 17;11(1):3949. Epub 2021 Feb 17.

Neurosciences and Mental Health, Hospital for Sick Children, 686 Bay Street, Toronto, ON, M5G 0A4, Canada.

A left perisylvian network is known to support language in healthy adults. Low-beta (13-23 Hz) event-related desynchrony (ERD) has been observed during verb generation, at approximately 700-1200 ms post-stimulus presentation in past studies; the signal is known to reflect increased neuronal firing and metabolic demand during language production. In contrast, concurrent beta event-related synchrony (ERS) is thought to reflect neuronal inhibition but has not been well studied in the context of language. Further, while low-beta ERD for expressive language has been found to gradually shift from bilateral in childhood to left hemispheric by early adulthood, developmental lateralization of ERS has not been established. We used magnetoencephalography to study low beta ERS lateralization in a group of children and adolescents (n = 78), aged 4 to less than 19 years, who performed covert verb generation. We found that the youngest children had bilateral ERD and ERS. By adolescence, low-beta ERD was predominantly left lateralized in perisylvian cortex (i.e., Broca's and Wernicke's regions), while beta ERS was predominantly right lateralized. Increasing lateralization was significantly correlated to age for both ERD (Spearman's r = 0.45, p < 0.01) and ERS (Spearman's r =  - 0.44, p < 0.01). Interestingly, while ERD lateralized in a linear manner, ERS lateralization followed a nonlinear trajectory, suggesting distinct developmental trajectories. Implications to early-age neuroplasticity and neuronal inhibition are discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-021-83373-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7889886PMC
February 2021

Multilayer Connector Hub Mapping Reveals Key Brain Regions Supporting Expressive Language.

Brain Connect 2021 Feb 18;11(1):45-55. Epub 2021 Jan 18.

Neurosciences and Mental Health, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.

How components of the distributed brain networks that support cognition participate in typical functioning remains a largely unanswered question. An important subgroup of regions in the larger network are , which are areas that are highly connected to several other functionally specialized sets of regions, and are likely important for sensorimotor integration. The present study attempts to characterize involved in typical expressive language functioning using a data-driven, multimodal, full multilayer magnetoencephalography (MEG) connectivity-based pipeline. Twelve adolescents, 16-18 years of age (five males), participated in this study. Participants underwent MEG scanning during a verb generation task. MEG and structural connectivity were calculated at the whole-brain level. Amplitude/amplitude coupling (AAC) was used to compute functional connections both within and between discrete frequency bins. AAC values were then multiplied by a binary structural connectivity matrix, and then entered into full multilayer network analysis. Initially, hubs were defined based on multilayer versatility and subsequently reranked by a novel measure called delta centrality on interconnectedness (DCI). DCI is defined as the percent change in interfrequency interconnectedness after removal of a hub. We resolved regions that are important for between-frequency communication among other areas during expressive language, with several potential theoretical and clinical applications that can be generalized to other cognitive domains. Our multilayer, data-driven framework captures nonlinear connections that span across scales that are often missed in conventional analyses. The present study suggests that crucial hubs may be conduits for interfrequency communication between action and perception systems that are crucial for typical functioning.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/brain.2020.0776DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7891212PMC
February 2021

Extremely Preterm Children Demonstrate Interhemispheric Hyperconnectivity During Verb Generation: a Multimodal Approach.

medRxiv 2020 Nov 4. Epub 2020 Nov 4.

Hospital for Sick Children, Neurosciences and Mental Health.

Children born extremely preterm (EPT, <28 weeks gestation) are at risk for delays in development, including language. We use fMRI-constrained magnetoencephalography (MEG) during a verb generation task to assess the extent and functional connectivity (phase locking value, or PLV) of language networks in a large cohort of EPT children and their term comparisons (TC). 73 participants, aged 4 to 6 years, were enrolled (42 TC, 31 EPT). There were no significant group differences in age, sex, race, ethnicity, parental education, or family income. There were significant group differences in expressive language scores (p<0.05). Language representation was not significantly different between groups on fMRI, with task-specific activation involving bilateral temporal and left inferior frontal cortex. There were group differences in functional connectivity seen in MEG. To identify a possible subnetwork contributing to focal spectral differences in connectivity, we ran Network Based Statistics analyses. For both beta (20-25 Hz) and gamma (61-70 Hz) bands, we observed a subnetwork showing hyperconnectivity in the EPT group (p<0.05). Network strength was computed for the beta and gamma subnetworks and assessed for correlation with language performance. For the EPT group, exclusively, strength of the subnetwork identified in the gamma frequency band was positively correlated with expressive language scores (r=0.318, p<0.05). Thus, interhemispheric hyperconnectivity is positively related to language for EPT children and might represent a marker for resiliency in this population.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1101/2020.10.30.20222448DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7654860PMC
November 2020

Cortical and subcortical volume differences between Benign Epilepsy with Centrotemporal Spikes and Childhood Absence Epilepsy.

Epilepsy Res 2020 10 23;166:106407. Epub 2020 Jun 23.

Division of Neurology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave. Cincinnati, OH, 45229, USA; Pediatric Neuroimaging Research Consortium, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave. Cincinnati, OH, 45229, USA. Electronic address:

Objective: Benign Childhood Epilepsy with Centrotemporal Spikes (BECTS) and Childhood Absence Epilepsy (CAE) are the most common childhood epilepsy syndromes and they share a similar age-dependence. However, the two syndromes clearly differ in seizures and EEG patterns. The aim of this study is to investigate whether children of the same age with BECTS, CAE and typically-developing children have significant differences in grey matter volume that may underlie the different profiles of these syndromes.

Methods: Twenty one patients with newly-diagnosed BECTS and 18 newly diagnosed and drug naïve CAE were included and compared to 31 typically-developing children. Voxel-based morphometry was utilized to investigate grey matter volume differences among BECTS, CAE, and controls. We also examined the effect of age on grey matter volume in all three groups. In addition to the whole brain analysis, we chose regions of interest analysis based on previous literature suggesting the involvement of these regions in BECTS or CAE. The group differences of grey matter volume was tested with 2-sample t-test for between two groups' comparisons and ANOVA for three group comparisons.

Results: In the whole brain group comparisons, the grey matter volume in CAE was significantly decreased in the areas of right inferior frontal and anterior temporal compared to BECTS and controls (F  = 27.53, p < 0.001). In the control group, grey matter volume in bifrontal lobes showed a negative correlation with age (r=-0.54, p < 0.05), whereas no correlation was found in either CAE or BECTS. With ROI analyses, the grey matter volume of posterior thalami was increased in CAE compared to other 2 groups (p < 0.05).

Significance: This study shows that there are grey matter volume differences between CAE and BECTS. Our findings of grey matter volume differences may suggest that there may be localized, specific differences in brain structure between these two types of epilepsy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.eplepsyres.2020.106407DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7494623PMC
October 2020

Extremely preterm children exhibit altered cortical thickness in language areas.

Sci Rep 2020 07 2;10(1):10824. Epub 2020 Jul 2.

Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Canada.

Children born extremely preterm (< 28 weeks gestation, EPT) are at increased risk for language and other neurocognitive deficits compared to term controls (TC). Prior studies have reported both increases and decreases in cortical thickness in EPT across the cerebrum. These studies have not formally normalized for intracranial volume (ICV), which is especially important as EPT children often have smaller stature, head size, and ICV. We previously reported increased interhemispheric functional and structural connectivity in a well-controlled group of school-aged EPT children with no known brain injury or neurological deficits. Functional and structural hyperconnectivity between left and right temporoparietal regions was positively related with language scores in EPT, which may be reflected in measures of cortical thickness. To characterize possible language network cortical thickness effects, 15 EPT children and 15 TC underwent standardized assessments of language and structural magnetic resonance imaging at 4 to 6 years of age. Images were subjected to volumetric and cortical thickness analyses using FreeSurfer. Whole-brain analyses of cortical thickness were conducted both with and without normalization by ICV. Non-normalized results showed thinner temporal cortex for EPT, while ICV-normalized results showed thicker cortical regions in the right temporal lobe (FDRq = 0.05). Only ICV-normalized results were significantly related to language scores, with right temporal cortical thickness being positively correlated with performance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-67662-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7331674PMC
July 2020

Effect of continuous cooling on inhibition and attention while wearing firefighter's PPE in a hot environment.

J Occup Environ Hyg 2020 05 9;17(5):243-252. Epub 2020 Mar 9.

National Personal Protective Technology Laboratory (NPPTL), National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC), Pittsburgh, Pennsylvania.

Firefighting is physically and mentally strenuous, requiring rapid, appropriate decision-making in hot environments. Intact cognitive function is imperative to firefighters' effectiveness and safety. The study purpose was to investigate the effect of hyperthermia and the effect of body cooling on sustained attention and response inhibition while wearing firefighters' personal protective ensembles after exercise in a hot environment. Twelve healthy males were recruited to participate in two randomly assigned exercise sessions (walking on a treadmill for 40 min at 40% [Formula: see text] O while wearing firefighter's protective ensemble) in a hot environment: control (no cooling) and intervention (cooling). For intervention sessions, a cooling garment was worn underneath firefighter's protective ensemble and infused with 18 °C water supplied by an external water circulator. Participants performed a computerized Go/No-Go (a measure of cognitive function) test three times at baseline and post-exercise for each experimental session. Participants completed baseline testing while wearing cotton athletic clothing. The exercise continued until the core temperature reached ∼39 °C (for all subjects regardless of cooling or non-cooling experimental sessions). Following hyperthermia, participants' physiological responses were significantly increased after exercise. Subjects' reaction time was significantly reduced (improved) after experiencing thermal strain and reaching hyperthermia. The cooling method had a significant impact on suppressing the physiological load, i.e., body cooling delayed the time to reach a T of 39 °C (p ≤ 0.05), but not cognitive inhibition and attention (reaction time and accuracy). Unexpectedly, hyperthermia resulted in shorter reaction time following exercise (16.64 ± 5.62; p < 0.03), likely influenced by increased attention/vigilance. Hyperthermia may trigger an acute increase in alertness, causing decreased reaction time.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/15459624.2020.1726933DOI Listing
May 2020

Rewiring the extremely preterm brain: Altered structural connectivity relates to language function.

Neuroimage Clin 2020 22;25:102194. Epub 2020 Jan 22.

Neurosciences and Mental Health Research Institute, Hospital for Sick Children, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, Canada.

Children born preterm are at increased risk for cognitive impairment, with higher-order functions such as language being especially vulnerable. Previously, we and others have reported increased interhemispheric functional connectivity in children born extremely preterm; the finding appears at odds with literature showing decreased integrity of the corpus callosum, the primary commissural bundle, in preterm children. We address the apparent discrepancy by obtaining advanced measures of structural connectivity in twelve school-aged children born extremely preterm (<28 weeks) and ten term controls. We hypothesize increased extracallosal structural connectivity might support the functional hyperconnectivity we had previously observed. Participants were aged four to six years at time of study and groups did not differ in age, sex, race, ethnicity, or socioeconomic status. Whole-brain and language-network-specific (functionally-constrained) connectometry analyses were performed. At the whole-brain level, preterm children had decreased connectivity in the corpus callosum and increased connectivity in the cerebellum versus controls. Functionally-constrained analyses revealed significantly increased extracallosal connectivity between bilateral temporal regions in preterm children (FDRq <0.05). Connectivity within these extracallosal pathways was positively correlated with performance on standardized language assessments in children born preterm (FDRq <0.001), but unrelated to performance in controls. This is the first study to identify anatomical substrates for increased interhemispheric functional connectivity in children born preterm; increased reliance on an extracallosal pathway may represent a biomarker for resiliency following extremely preterm birth.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.nicl.2020.102194DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7005506PMC
January 2021

Hyperconnectivity during screen-based stories listening is associated with lower narrative comprehension in preschool children exposed to screens vs dialogic reading: An EEG study.

PLoS One 2019 22;14(11):e0225445. Epub 2019 Nov 22.

Educational Neuroimaging Center, Faculty of Education in Science and Technology, Technion, Haifa, Israel.

Objectives: Dialogic reading (DR) is a shared storybook reading intervention previously shown to have a positive effect on both literacy and general language skills. The aim of this study was to examine the effect of DR compared to screen-based intervention on electrophysiological markers supporting narrative comprehension using EEG.

Methods: Thirty-two typically developing preschoolers, ages 4 to 6 years, were assigned to one of two intervention groups: Dialogic Reading Group (DRG, n = 16) or Screen Story Group (SSG, n = 16). We examined the effect of intervention type using behavioral assessment and a narrative comprehension task with EEG.

Results: The DRG showed improved vocabulary and decreased functional connectivity during the stories-listening task, whereas the SSG group showed no changes in vocabulary or connectivity. Significantly decreased network strength and transitivity and increased network efficiency were observed in the DRG following intervention. Greater network strength and transitivity at follow-up were correlated with increased vocabulary.

Conclusions: The results suggest the beneficial effect of DR in preschool-age children on vocabulary and EEG-bands related to attention in the ventral stream during narrative comprehension. Decreased functional connectivity may serve as a marker for language gains following reading intervention.

Significance: DR intervention for preschool-age children may reduce interfering connections related to attention, which is related to better narrative comprehension.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0225445PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6874384PMC
March 2020

Neural indices of listening effort in noisy environments.

Sci Rep 2019 08 2;9(1):11278. Epub 2019 Aug 2.

Communication Sciences Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, USA.

Listening in a noisy environment is challenging for individuals with normal hearing and can be a significant burden for those with hearing impairment. The extent to which this burden is alleviated by a hearing device is a major, unresolved issue for rehabilitation. Here, we found adult users of cochlear implants (CIs) self-reported listening effort during a speech-in-noise task that was positively related to alpha oscillatory activity in the left inferior frontal cortex, canonical Broca's area, and inversely related to speech envelope coherence in the 2-5 Hz range originating in the superior-temporal plane encompassing auditory cortex. Left frontal cortex coherence in the 2-5 Hz range also predicted speech-in-noise identification. These data demonstrate that neural oscillations predict both speech perception ability in noise and listening effort.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-019-47643-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6677804PMC
August 2019

Detrended connectometry analysis to assess white matter correlates of performance in childhood.

Neuroimage 2019 02 24;186:637-646. Epub 2018 Nov 24.

Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; College of Medicine, Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA; Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA. Electronic address:

The white matter of the brain develops in a robust, regionally-variant, nonlinear manner during childhood. To relate white matter connectivity to performance, these regional nonlinear effects of age must be accounted for. Here, we identify white matter correlates of gross intellectual functioning using cutting-edge diffusion analyses inside a data-driven two-step regression framework. A total of 98 participants, ages 3-18 years, were included in the analyses. First, white matter connectivity was modeled as a function of age for each fiber direction at each voxel, extracted from the spin distribution function, using a 6-order B-spline. The smoothing parameter for each direction was chosen by minimizing generalized cross-validation (GCV), which prevents overfitting while remaining sensitive to potentially nonlinear effects of age. In the second step, the resulting Gaussian residuals were modeled as a function of either full-scale IQ (FSIQ), or of verbal IQ (VIQ) and performance IQ (PIQ), using a linear regression framework (connectometry). Graph theoretical analyses were also performed to assess how each predictor relates to global topological changes, including average clustering coefficient, characteristic path length, global efficiency, average local efficiency, and small worldness. Analyses revealed widespread positive associations between white matter connectivity and FSIQ, including regions of the corpus callosum, fornix, and corticothalamic tracts (FDRq < .05). A separate regression model revealed a selective positive relationship between VIQ and white matter connectivity in predominately frontal tracts (e.g., anterior corticothalamic radiations, fornix, anterior corpus callosum, frontopontine tracts); in contrast, PIQ predicted white matter connectivity in the posterior brain (e.g. parietopontine tracts, posterior corticothalamic radiations, posterior corticostriatal projections), (FDRq < .05). No negative correlations were observed. Graph analyses revealed FSIQ, VIQ while controlling for PIQ, and PIQ while controlling for VIQ increase clustering coefficient, global efficiency, local efficiency, and small worldness, and decrease characteristic path length of the network. Results indicate regional white matter changes related to cognitive skills in childhood, independent of age.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neuroimage.2018.11.043DOI Listing
February 2019

Cortical morphology, epileptiform discharges, and neuropsychological performance in BECTS.

Acta Neurol Scand 2018 Nov 10;138(5):432-440. Epub 2018 Jul 10.

Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.

Objectives: The aim of this study was to understand the relationship between cortical morphology, centrotemporal spike (CTS), and neuropsychological functioning in children with BECTS compared to their typically developing peers.

Materials And Methods: To examine whole-brain differences in cortical thickness between groups, a general linear model approach was applied to T1-weighted structural magnetic resonance imaging (MRI) in children with BECTS and typically developing children. Further region-of-interest (ROI) analyses were performed to examine the effects of frequency and lateralization of CTS. In addition, the relationship between Processing Speed Index (PSI) and cortical thickness was investigated.

Results: Twenty-three patients with BECTS and thirty-two controls were included. There was no statistically significant difference in global cortical thickness between groups. With ROI analyses, we found significantly thinner cortex within right pars opercularis when comparing children with right predominant CTS, and with very frequent right CTS (>10/min) to the control group (P = 0.028 and P = 0.026, respectively). A statistically significant interaction of group (controls vs BECTS) and PSI was seen in bilateral frontal and right superior parietal cortices, indicating a positive relationship between cortical thickness and PSI in healthy controls but not BECTS.

Conclusion: A region of cortex where right CTS may originate was thinner in BECTS compared to children without BECTS. Typically developing children with faster processing speed had thicker cortices in regions supporting visuomotor integration, motor, and executive function, but this relationship was not observed in BECTS. These results suggest that BECTS is associated with atypical cortical morphology that may underlie poorer neuropsychological performance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ane.12997DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6175642PMC
November 2018

Whole-brain MEG connectivity-based analyses reveals critical hubs in childhood absence epilepsy.

Epilepsy Res 2018 09 4;145:102-109. Epub 2018 Jun 4.

Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical Center, Cincinnati OH, USA; Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; College of Medicine, Department of Pediatrics, University of Cincinnati, Cincinnati OH, USA. Electronic address:

Absence seizures are thought to be linked to abnormal interplays between regions of a thalamocortical network. However, the complexity of this widespread network makes characterizing the functional interactions among various brain regions challenging. Using whole-brain functional connectivity and network analysis of magnetoencephalography (MEG) data, we explored pre-treatment brain hubs ("highly connected nodes") of patients aged 6 to 12 years with childhood absence epilepsy. We analyzed ictal MEG data of 74 seizures from 16 patients. We employed a time-domain beamformer technique to estimate MEG sources in broadband (1-40 Hz) where the greatest power changes between ictal and preictal periods were identified. A phase synchrony measure, phase locking value, and a graph theory metric, eigenvector centrality (EVC), were utilized to quantify voxel-level connectivity and network hubs of ictal > preictal periods, respectively. A volumetric atlas containing 116 regions of interests (ROIs) was utilized to summarize the network measures. ROIs with EVC (z-score) > 1.96 were reported as critical hubs. ROIs analysis revealed functional-anatomical hubs in a widespread network containing bilateral precuneus (right/left, z = 2.39, 2.18), left thalamus (z = 2.28), and three anterior cerebellar subunits of lobule "IV-V" (z = 3.9), vermis "IV-V" (z = 3.57), and lobule "III" (z = 2.03). Findings suggest that highly connected brain areas or hubs are present in focal cortical, subcortical, and cerebellar regions during absence seizures. Hubs in thalami, precuneus and cingulate cortex generally support a theory of rapidly engaging and bilaterally distributed networks of cortical and subcortical regions responsible for seizures generation, whereas hubs in anterior cerebellar regions may be linked to terminating motor automatisms frequently seen during typical absence seizures. Whole-brain network connectivity is a powerful analytic tool to reveal focal components of absence seizures in MEG. Our investigations can lead to a better understanding of the pathophysiology of CAE.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.eplepsyres.2018.06.001DOI Listing
September 2018

fMRI connectivity of expressive language in young children and adolescents.

Hum Brain Mapp 2018 09 2;39(9):3586-3596. Epub 2018 May 2.

Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.

Studies of language representation in development have shown a bilateral distributed pattern of activation that becomes increasingly left-lateralized and focal from young childhood to adulthood. However, the level by which canonical and extra-canonical regions, including subcortical and cerebellar regions, contribute to language during development has not been well-characterized. In this study, we employed fMRI connectivity analyses (fcMRI) to characterize the distributed network supporting expressive language in a group of young children (age 4-6) and adolescents (age 16-18). We conducted an fcMRI analysis using seed-to-voxel and seed-to-ROI (region of interest) strategies to investigate interactions of left pars triangularis with other brain areas. The analyses showed significant interhemispheric connectivity in young children, with a minimal connectivity of the left pars triangularis to subcortical and cerebellar regions. In contrast, adolescents showed significant connectivity between the left IFG seed and left perisylvian cortex, left caudate and putamen, and regions of the right cerebellum. Importantly, fcMRI analyses indicated significant differences between groups at 3 anatomical clusters, including left IFG, left supramarginal gyrus, and right cerebellar crura, suggesting a role in the functional development of language.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/hbm.24196DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6866395PMC
September 2018

Extremely preterm children exhibit increased interhemispheric connectivity for language: findings from fMRI-constrained MEG analysis.

Dev Sci 2018 11 16;21(6):e12669. Epub 2018 Apr 16.

Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio, USA.

Children born extremely preterm are at significant risk for cognitive impairment, including language deficits. The relationship between preterm birth and neurological changes that underlie cognitive deficits is poorly understood. We use a stories-listening task in fMRI and MEG to characterize language network representation and connectivity in children born extremely preterm (n = 15, <28 weeks gestation, ages 4-6 years), and in a group of typically developing control participants (n = 15, term birth, 4-6 years). Participants completed a brief neuropsychological assessment. Conventional fMRI analyses revealed no significant differences in language network representation across groups (p > .05, corrected). The whole-group fMRI activation map was parcellated to define the language network as a set of discrete nodes, and the timecourse of neuronal activity at each position was estimated using linearly constrained minimum variance beamformer in MEG. Virtual timecourses were subjected to connectivity and network-based analyses. We observed significantly increased beta-band functional connectivity in extremely preterm compared to controls (p < .05). Specifically, we observed an increase in connectivity between left and right perisylvian cortex. Subsequent effective connectivity analyses revealed that hyperconnectivity in preterms was due to significantly increased information flux originating from the right hemisphere (p < 0.05). The total strength and density of the language network were not related to language or nonverbal performance, suggesting that the observed hyperconnectivity is a "pure" effect of prematurity. Although our extremely preterm children exhibited typical language network architecture, we observed significantly altered network dynamics, indicating reliance on an alternative neural strategy for the language task.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/desc.12669DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6193851PMC
November 2018

Ictal connectivity in childhood absence epilepsy: Associations with outcome.

Epilepsia 2018 05 6;59(5):971-981. Epub 2018 Apr 6.

Division of Neurology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.

Objective: The understanding of childhood absence epilepsy (CAE) has been revolutionized over the past decade, but the biological mechanisms responsible for variable treatment outcomes are unknown. Our purpose in this prospective observational study was to determine how pretreatment ictal network pathways, defined using a combined electroencephalography (EEG)-functional magnetic resonance imaging (EEG-fMRI) and magnetoencephalography (MEG) effective connectivity analysis, were related to treatment response.

Methods: Sixteen children with newly diagnosed and drug-naive CAE had 31 typical absence seizures during EEG-fMRI and 74 during MEG. The spatial extent of the pretreatment ictal network was defined using fMRI hemodynamic response with an event-related independent component analysis (eICA). This spatially defined pretreatment ictal network supplied prior information for MEG-effective connectivity analysis calculated using phase slope index (PSI). Treatment outcome was assessed 2 years following diagnosis and dichotomized to ethosuximide (ETX)-treatment responders (N = 11) or nonresponders (N = 5). Effective connectivity of the pretreatment ictal network was compared to the treatment response.

Results: Patterns of pretreatment connectivity demonstrated strongest connections in the thalamus and posterior brain regions (parietal, posterior cingulate, angular gyrus, precuneus, and occipital) at delta frequencies and the frontal cortices at gamma frequencies (P < .05). ETX treatment nonresponders had pretreatment connectivity, which was decreased in the precuneus region and increased in the frontal cortex compared to ETX responders (P < .05).

Significance: Pretreatment ictal connectivity differences in children with CAE were associated with response to antiepileptic treatment. This is a possible mechanism for the variable treatment response seen in patients sharing the same epilepsy syndrome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/epi.14067DOI Listing
May 2018

Mapping Critical Language Sites in Children Performing Verb Generation: Whole-Brain Connectivity and Graph Theoretical Analysis in MEG.

Front Hum Neurosci 2017 5;11:173. Epub 2017 Apr 5.

Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical CenterCincinnati, OH, USA.

A classic left frontal-temporal brain network is known to support language processes. However, the level of participation of constituent regions, and the contribution of extra-canonical areas, is not fully understood; this is particularly true in children, and in individuals who have experienced early neurological insult. In the present work, we propose whole-brain connectivity and graph-theoretical analysis of magnetoencephalography (MEG) source estimates to provide robust maps of the pediatric expressive language network. We examined neuromagnetic data from a group of typically-developing young children ( = 15, ages 4-6 years) and adolescents ( = 14, 16-18 years) completing an auditory verb generation task in MEG. All source analyses were carried out using a linearly-constrained minimum-variance (LCMV) beamformer. Conventional differential analyses revealed significant ( < 0.05, corrected) low-beta (13-23 Hz) event related desynchrony (ERD) focused in the left inferior frontal region (Broca's area) in both groups, consistent with previous studies. Connectivity analyses were carried out in broadband (3-30 Hz) on time-course estimates obtained at the voxel level. Patterns of connectivity were characterized by (PLV), and network hubs identified through . Hub analysis revealed the importance of left perisylvian sites, i.e., Broca's and Wernicke's areas, across groups. The hemispheric distribution of frontal and temporal lobe EVC values was asymmetrical in most subjects; left dominant EVC was observed in 20% of young children, and 71% of adolescents. Interestingly, the adolescent group demonstrated increased critical sites in the right cerebellum, left inferior frontal gyrus (IFG) and left putamen. Here, we show that whole brain connectivity and network analysis can be used to map critical language sites in typical development; these methods may be useful for defining the margins of eloquent tissue in neurosurgical candidates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fnhum.2017.00173DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5380724PMC
April 2017

Cortical Alpha Oscillations Predict Speech Intelligibility.

Front Hum Neurosci 2017 24;11:88. Epub 2017 Feb 24.

Communication Sciences Research Center, Cincinnati Children's Hospital Medical CenterCincinnati, OH, USA; Department of Otolaryngology, University of CincinnatiCincinnati, OH, USA.

Understanding speech in noise (SiN) is a complex task involving sensory encoding and cognitive resources including working memory and attention. Previous work has shown that brain oscillations, particularly alpha rhythms (8-12 Hz) play important roles in sensory processes involving working memory and attention. However, no previous study has examined brain oscillations during performance of a continuous speech perception test. The aim of this study was to measure cortical alpha during attentive listening in a commonly used SiN task (digits-in-noise, DiN) to better understand the neural processes associated with "top-down" cognitive processing in adverse listening environments. We recruited 14 normal hearing (NH) young adults. DiN speech reception threshold (SRT) was measured in an initial behavioral experiment. EEG activity was then collected: (i) while performing the DiN near SRT; and (ii) while attending to a silent, close-caption video during presentation of identical digit stimuli that the participant was instructed to ignore. Three main results were obtained: (1) during attentive ("active") listening to the DiN, a number of distinct neural oscillations were observed (mainly alpha with some beta; 15-30 Hz). No oscillations were observed during attention to the video ("passive" listening); (2) overall, alpha event-related synchronization (ERS) of central/parietal sources were observed during active listening when data were grand averaged across all participants. In some participants, a smaller magnitude alpha event-related desynchronization (ERD), originating in temporal regions, was observed; and (3) when individual EEG trials were sorted according to correct and incorrect digit identification, the temporal alpha ERD was consistently greater on correctly identified trials. No such consistency was observed with the central/parietal alpha ERS. These data demonstrate that changes in alpha activity are specific to listening conditions. To our knowledge, this is the first report that shows almost no brain oscillatory changes during a passive task compared to an active task in any sensory modality. Temporal alpha ERD was related to correct digit identification.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fnhum.2017.00088DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5323373PMC
February 2017

Changes of White Matter Diffusion Anisotropy in Response to a 6-Week iPad Application-Based Occupational Therapy Intervention in Children with Surgically Treated Hydrocephalus: A Pilot Study.

Neuropediatrics 2016 Oct 20;47(5):336-40. Epub 2016 Jul 20.

University of Cincinnati College of Medicine, Cincinnati, Ohio, United States.

Objective Our aims were (1) to test whether diffusion tensor imaging (DTI) could detect underlying white matter (WM) changes after a 6-week iPad application-based occupational therapy (OT) intervention in children with surgically treated hydrocephalus (HCP); and (2) to explore the association between WM changes and performance outcomes. Methods Five children (age range: 6.05-9.10 years) with surgically treated HCP completed an intensive iPad-based OT intervention targeting common domains of long-term deficits in children with HCP. The intervention included 6 weekly sessions in an OT clinic supplementing home-based program (1 hour/day, 4 days/week). DTI and neuropsychological assessments were performed before and after the intervention. Observation After the therapy, significant increases in fractional anisotropy (FA) and/or decreases in radial diffusivity were found in extensive WM areas. All participants demonstrated an increased perceptual reasoning index (PRI, Wechsler Abbreviated Scale of Intelligence: 2nd edition, PRI gains = 14.20 ± 7.56, p = 0.014). A significant positive correlation was found between PRI increase and the increase of FA in the right posterior limb of the internal capsule and the right external capsule (both p < 0.05). Conclusion This study provides initial evidence of DTI's sensitivity to detect subtle WM changes associated with performance improvements in response to a 6-week OT intervention in children with HCP.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1055/s-0036-1584938DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5035702PMC
October 2016

Obese adolescents with type 2 diabetes perform worse than controls on cognitive and behavioral assessments.

Pediatr Diabetes 2017 06 29;18(4):297-303. Epub 2016 Mar 29.

Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.

Background: Children with type 1 diabetes demonstrate worse cognitive performance compared with their peers. Little is known regarding the cognitive and behavioral performance in obese adolescents with type 2 diabetes.

Methods: Cross sectional evaluation of 20 obese adolescents with type 2 diabetes and 20 healthy adolescents was performed in Cincinnati, Ohio. Cognitive tests that included measures of processing speed, working memory, verbal and semantic fluency and parent reports of executive function and problem behavior were compared. Academic achievement and the relationship between cognitive/behavioral scores and diabetes duration and diabetes control (hemoglobin A1c) were assessed in the type 2 diabetes group only.

Results: The type 2 diabetes group had mean duration of diabetes of 2.8 ± 2.2 yr and hemoglobin A1c of 7.9 ± 2.2%. Adolescents with type 2 diabetes scored lower than controls on tests of working and verbal memory and processing speed (all p < 0.05) and worse for Internalizing, Externalizing, and Total Problems behaviors on the Child Behavior Checklist (all p < 0.05). Adolescents with type 2 diabetes scored below the population mean in academic achievement, most notably calculation. Working memory and processing speed were negatively correlated with duration of diabetes (r = -0.50 and -0.47, respectively, p < 0.05).

Conclusions: Obese youth with type 2 diabetes score poorly compared with controls on multiple assessments of cognitive function and adaptive behavior. Further work is needed to determine if these effects are driven by obesity, diabetes or other demographic and socioeconomic risk factors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/pedi.12383DOI Listing
June 2017

Auditory cortical activity to different voice onset times in cochlear implant users.

Clin Neurophysiol 2016 Feb 10;127(2):1603-1617. Epub 2015 Nov 10.

Communication Sciences Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Otolaryngology, College of Medicine, University of Cincinnati, Cincinnati, OH, USA. Electronic address:

Objective: Voice onset time (VOT) is a critical temporal cue for perception of speech in cochlear implant (CI) users. We assessed the cortical auditory evoked potentials (CAEPs) to consonant vowels (CVs) with varying VOTs and related these potentials to various speech perception measures.

Methods: CAEPs were recorded from 64 scalp electrodes during passive listening in CI and normal-hearing (NH) groups. Speech stimuli were synthesized CVs from a 6-step VOT /ba/-/pa/ continuum ranging from 0 to 50 ms VOT in 10-ms steps. Behavioral measures included the 50% boundary point for categorical perception ("ba" to "pa") from an active condition task.

Results: Behavioral measures: CI users with poor speech perception performance had prolonged 50% VOT boundary points compared to NH subjects. The 50% boundary point was also significantly correlated to the ability to discriminate consonants in quiet and noise masking. Electrophysiology: The most striking difference between the NH and CI subjects was that the P2 response was significantly reduced in amplitude in the CI group compared to NH. N1 amplitude did not differ between NH and CI groups. P2 latency increased with increases in VOT for both NH and CI groups. P2 was delayed more in CI users with poor speech perception compared to NH subjects. N1 amplitude was significantly related to consonant perception in noise while P2 latency was significantly related to vowel perception in noise. When dipole source modelling in auditory cortex was used to characterize N1/P2, more significant relationships were observed with speech perception measures compared to the same N1/P2 activity when measured at the scalp. N1 dipole amplitude measures were significantly correlated with consonants in noise discrimination. Like N1, the P2 dipole amplitude was correlated with consonant discrimination, but additional significant relationships were observed such as sentence and word identification.

Conclusions: P2 responses to a VOT continuum stimulus were different between NH subjects and CI users. P2 responses show more significant relationships with speech perception than N1 responses.

Significance: The current findings indicate that N1/P2 measures during a passive listening task relate to speech perception outcomes after cochlear implantation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.clinph.2015.10.049DOI Listing
February 2016

Characterizing Information Flux Within the Distributed Pediatric Expressive Language Network: A Core Region Mapped Through fMRI-Constrained MEG Effective Connectivity Analyses.

Brain Connect 2016 Feb 2;6(1):76-83. Epub 2015 Dec 2.

1 Pediatric Neuroimaging Research Consortium, Cincinnati Children's Hospital Medical Center , Cincinnati, Ohio.

Using noninvasive neuroimaging, researchers have shown that young children have bilateral and diffuse language networks, which become increasingly left lateralized and focal with development. Connectivity within the distributed pediatric language network has been minimally studied, and conventional neuroimaging approaches do not distinguish task-related signal changes from those that are task essential. In this study, we propose a novel multimodal method to map core language sites from patterns of information flux. We retrospectively analyze neuroimaging data collected in two groups of children, ages 5-18 years, performing verb generation in functional magnetic resonance imaging (fMRI) (n = 343) and magnetoencephalography (MEG) (n = 21). The fMRI data were conventionally analyzed and the group activation map parcellated to define node locations. Neuronal activity at each node was estimated from MEG data using a linearly constrained minimum variance beamformer, and effective connectivity within canonical frequency bands was computed using the phase slope index metric. We observed significant (p ≤ 0.05) effective connections in all subjects. The number of suprathreshold connections was significantly and linearly correlated with participant's age (r = 0.50, n = 21, p ≤ 0.05), suggesting that core language sites emerge as part of the normal developmental trajectory. Across frequencies, we observed significant effective connectivity among proximal left frontal nodes. Within the low frequency bands, information flux was rostrally directed within a focal, left frontal region, approximating Broca's area. At higher frequencies, we observed increased connectivity involving bilateral perisylvian nodes. Frequency-specific differences in patterns of information flux were resolved through fast (i.e., MEG) neuroimaging.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/brain.2015.0374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4744880PMC
February 2016

Changes in voice onset time and motor speech skills in children following motor speech therapy: Evidence from /pa/ productions.

Clin Linguist Phon 2014 Jun 21;28(6):396-412. Epub 2014 Jan 21.

Program in Neurosciences and Mental Health, Sick Kids Research Institute , Toronto, Ontario , Canada .

This study evaluated changes in motor speech control and inter-gestural coordination for children with speech sound disorders (SSD) subsequent to Prompts for Restructuring Oral and Muscular Phonetic Targets (PROMPT) intervention. We measured the distribution patterns of voice onset time (VOT) for a voiceless stop (/p/) to examine the changes in inter-gestural coordination. Two standardized tests were used (Verbal Motor Production Assessment for Children (VMPAC), GFTA-2) to assess the changes in motor speech skills and articulation. Data showed positive changes in patterns of VOT with a lower pattern of variability. All children showed significantly higher scores for VMPAC, but only some children showed higher scores for GFTA-2. Results suggest that the proprioceptive feedback provided through PROMPT had a positive influence on speech motor control and inter-gestural coordination in voicing behavior. This set of VOT data for children with SSD adds to our understanding of the speech characteristics underlying speech motor control. Directions for future studies are discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3109/02699206.2013.874040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4885741PMC
June 2014

Cortical thickness in children receiving intensive therapy for idiopathic apraxia of speech.

Brain Topogr 2014 Mar 24;27(2):240-7. Epub 2013 Aug 24.

Division of Neurology, Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.

Children with idiopathic apraxia experience difficulties planning the movements necessary for intelligible speech. There is increasing evidence that targeted early interventions, such as Prompts for Restructuring Oral Muscular Phonetic Targets (PROMPT), can be effective in treating these disorders. In this study, we investigate possible cortical thickness correlates of idiopathic apraxia of speech in childhood, and changes associated with participation in an 8-week block of PROMPT therapy. We found that children with idiopathic apraxia (n = 11), aged 3-6 years, had significantly thicker left supramarginal gyri than a group of typically-developing age-matched controls (n = 11), t(20) = 2.84, p ≤ 0.05. Over the course of therapy, the children with apraxia (n = 9) experienced significant thinning of the left posterior superior temporal gyrus (canonical Wernicke's area), t(8) = 2.42, p ≤ 0.05. This is the first study to demonstrate experience-dependent structural plasticity in children receiving therapy for speech sound disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10548-013-0308-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3921462PMC
March 2014

Relationship between speech motor control and speech intelligibility in children with speech sound disorders.

J Commun Disord 2013 May-Jun;46(3):264-80. Epub 2013 Apr 6.

The Speech & Stuttering Institute, 2-150 Duncan Mill Road, Toronto, Ontario M3B 3M4, Canada.

Unlabelled: The current study was undertaken to investigate the impact of speech motor issues on the speech intelligibility of children with moderate to severe speech sound disorders (SSD) within the context of the PROMPT intervention approach. The word-level Children's Speech Intelligibility Measure (CSIM), the sentence-level Beginner's Intelligibility Test (BIT) and tests of speech motor control and articulation proficiency were administered to 12 children (3:11 to 6:7 years) before and after PROMPT therapy. PROMPT treatment was provided for 45 min twice a week for 8 weeks. Twenty-four naïve adult listeners aged 22-46 years judged the intelligibility of the words and sentences. For CSIM, each time a recorded word was played to the listeners they were asked to look at a list of 12 words (multiple-choice format) and circle the word while for BIT sentences, the listeners were asked to write down everything they heard. Words correctly circled (CSIM) or transcribed (BIT) were averaged across three naïve judges to calculate percentage speech intelligibility. Speech intelligibility at both the word and sentence level was significantly correlated with speech motor control, but not articulatory proficiency. Further, the severity of speech motor planning and sequencing issues may potentially be a limiting factor in connected speech intelligibility and highlights the need to target these issues early and directly in treatment.

Learning Outcomes: The reader will be able to: (1) outline the advantages and disadvantages of using word- and sentence-level speech intelligibility tests; (2) describe the impact of speech motor control and articulatory proficiency on speech intelligibility; and (3) describe how speech motor control and speech intelligibility data may provide critical information to aid treatment planning.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcomdis.2013.02.003DOI Listing
February 2014

Quality of life in young adults who underwent resective surgery for epilepsy in childhood.

Epilepsia 2012 Sep 19;53(9):1577-86. Epub 2012 Jul 19.

Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.

Purpose: This study investigated quality of life (QOL) in young adults who had undergone epilepsy surgery before the age of 16 years. The contribution to QOL of seizure status in the prior year, sex, number of antiepileptic drugs, and mood were evaluated.

Methods: Sixty-nine young adults who had undergone surgery were subdivided into those who were seizure-free in the past year (n = 38) and those who had seizures (n = 31) in that time. A nonsurgical comparison group of young adults (n = 29) with childhood-onset medically intractable epilepsy was also studied. All groups completed measures of QOL and mood.

Key Findings: After accounting for mood, sex, and number of antiepileptic drugs, the seizure-free group reported better cognitive and physical function and overall QOL, experienced less seizure worry, and had better self-perception. Mood was the most consistently predictive covariate, and was independently predictive of many aspects of QOL.

Significance: Seizure freedom associated with surgery in childhood is associated with improved QOL in certain domains. Findings highlight the importance of mood in determining self-perception of QOL.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1528-1167.2012.03594.xDOI Listing
September 2012

Characterizing the normal developmental trajectory of expressive language lateralization using magnetoencephalography.

J Int Neuropsychol Soc 2011 Sep 4;17(5):896-904. Epub 2011 Aug 4.

Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada.

To characterize the developmental trajectory for expressive language representation and to test competing explanations for the relative neuroplasticity of language in childhood, we studied 28 healthy children and adolescents (aged 5-19 years) participating in a covert verb generation task in magnetoencephalography. Lateralization of neuromagnetic responses in the frontal lobe was quantified using a bootstrap statistical thresholding procedure for differential beamformer analyses. We observed a significant positive correlation between left hemisphere lateralization and age. Findings suggest that adult-typical left hemisphere lateralization emerges from an early bilateral language network, which may explain the pediatric advantage for interhemispheric plasticity of language.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1017/S1355617711000932DOI Listing
September 2011

Self-reported symptoms of psychological well-being in young adults who underwent resective epilepsy surgery in childhood.

Epilepsia 2011 May 22;52(5):891-9. Epub 2011 Mar 22.

University of Toronto Mississauga, Mississauga, Ontario, Canada.

Purpose: This study investigated the relationship of childhood resective surgery for lesional epilepsy and recent seizure history on self-reported symptoms of mood and psychological distress in young adults (aged 18-30).

Methods: Ninety-eight individuals with epilepsy of childhood onset were divided into three groups: a seizure-free surgical group (n = 39), a surgical group still experiencing seizures (n = 31), and a nonsurgical epilepsy comparison group (n = 28). Participants completed two standardized questionnaires about current mood state and psychological and psychiatric symptoms: the Profile of Mood States (POMS) and the Symptom Checklist-90 Revised (SCL-90R).

Key Findings: Forty-eight percent of all participants reported a history of psychological problems. The percentage of the seizure-free surgical group who met the SCL-90R criteria for current clinically significant distress was statistically less than in the other groups. Those who were seizure free also reported significantly fewer total symptoms on the SCL-90R. The current number of antiepileptic medications was related to scores on a number of the scales.

Significance: These results provide modest support for the contention that seizure freedom after pediatric epilepsy surgery is associated with reduced risk for psychological distress during early adulthood.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1528-1167.2011.03026.xDOI Listing
May 2011

Localization of Broca's area using verb generation tasks in the MEG: validation against fMRI.

Neurosci Lett 2011 Mar 30;490(3):215-9. Epub 2010 Dec 30.

Division of Neurology, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8.

Functional MRI (fMRI) is routinely used to non-invasively localize language areas. Magnetoencephalography (MEG) is being explored as an alternative technique. MEG tasks to localize receptive language are well established although there are no standardized tasks to localize expressive language areas. We developed two expressive language tasks for MEG and validated their localizations against fMRI data. Ten right-handed adolescents (μ=17.5 years) were tested with fMRI and MEG on two tasks: verb generation to pictures and verb generation to words. MEG and fMRI data were normalized and overlaid. The number of overlapping voxels activated in fMRI and MEG were counted for each subject, for each task, at different thresholding levels. For picture verb generation, there was 100% concordance between MEG and fMRI lateralization, and for word verb generation, there was 75% concordance. A count showed 79.6% overlap of voxels activated by both MEG and fMRI for picture verb generation and 50.2% overlap for word verb generation. The percentage overlap decreased with increasingly stringent activation thresholds. Our novel MEG expressive language tasks successfully identified neural regions involved in language production and showed high concordance with fMRI laterality. Percentage overlap of activated voxels was also high when validated against fMRI, but showed task-specific and threshold-related effects. The high concordance and high percentage overlap between fMRI and MEG activations confirm the validity of our new MEG task. Furthermore, the higher concordance from the picture verb generation task suggests that this is a promising task for use in the young clinical population.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neulet.2010.12.055DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3076374PMC
March 2011

Pathology type does not predict language lateralization in children with medically intractable epilepsy.

Epilepsia 2009 Jun 13;50(6):1498-504. Epub 2009 Feb 13.

Department of Psychology, University of Toronto, Toronto, Ontario, Canada.

Purpose: We examined potential differences in the effects of pathology type on language lateralization in pediatric epilepsy.

Methods: We examined findings from intracarotid sodium amobarbital procedure (IAP/Wada) in a large consecutive sample of children with refractory epilepsy. Subjects were assigned to one of three pathology groups: developmental (n = 28), acquired (n = 26), and tumor (n = 20); groups were compared for language lateralization.

Results: Rates of atypical language lateralization did not differ across groups. Greater than half of the subjects with left hemisphere insults and seizure onset before 6 years of age had atypical language lateralization, independent of pathology type.

Discussion: Atypical language lateralization may occur in the context of developmental, acquired, and/or tumor pathology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1528-1167.2008.02014.xDOI Listing
June 2009