Visuospatial processing skills following unilateral arterial ischemic stroke in childhood.

Due to the rare occurrence of childhood stroke, its impact on later cognitive functioning remains unclear. While it is often assumed that children recover better than adults, recent studies suggest that childhood stroke can negatively affect a wide range of cognitive domains, such as attention, language, and processing speed, among others. We examined the effect of unilateral stroke on children's visuoconstructive ability and visual memory. Seventeen children with left- or right-sided arterial ischemic stroke were tested using subtests of the Hamburg-Wechsler Intelligenztest für Kinder and the Rey-Osterrieth Complex Figure (ROCF). The ROCF was evaluated both quantitatively and qualitatively with the help of two separate scoring methods. We found that lesion laterality and age at stroke impacted childhood stroke patients' ability to recall certain elements of the figure. Regarding lesion laterality, left-sided stroke patients had more difficulties recalling internal details than right-sided stroke patients. In terms of age, patients with stroke onset before the age of 5 years remembered fewer structural elements than patients with stroke onset after the age of 5 years did. Moreover, the qualitative scoring method better differentiated between individuals and between groups than the more commonly used quantitative method. The results of this study not only highlight the importance of a qualitative assessment of the ROCF but could also aid clinicians in testing stroke patients more accurately and tailoring subsequent therapy to the patient's individual needs.

Cortical thickness in the right medial frontal gyrus predicts planning performance in healthy children and adolescents.

The ability to plan is an important part of the set of the cognitive skills called "executive functions." To be able to plan actions in advance is of great importance in everyday life and constitutes one of the major key features for academic as well as economic success. The present study aimed to investigate the neuroanatomical correlates of planning in normally developing children, as measured by the cortical thickness of the prefrontal cortex. Eighteen healthy children and adolescents underwent structural MRI examinations and the Tower of London (ToL) task. A multiple regression analysis revealed that the cortical thickness of the right caudal middle frontal gyrus (cMFG) was a significant predictor of planning performance. Neither the cortical thickness of any other prefrontal area nor gender were significantly associated with performance in the ToL task. The results of the present exploratory study suggest that the cortical thickness of the right, but not the left cMFG, is positively correlated with performance in the ToL task. We, therefore, conclude that increased cortical thickness may be more beneficial for higher-order processes, such as information integration, than for lower-order processes, such as the analysis of external information.

Effect of corpus callosum agenesis on the language network in children and adolescents.

The present study is interested in the role of the corpus callosum in the development of the language network. We, therefore, investigated language abilities and the language network using task-based fMRI in three cases of complete agenesis of the corpus callosum (ACC), three cases of partial ACC and six controls. Although the children with complete ACC revealed impaired functions in specific language domains, no child with partial ACC showed a test score below average. As a group, ACC children performed significantly worse than healthy controls in verbal fluency and naming. Furthermore, whole-brain ROI-to-ROI connectivity analyses revealed reduced intrahemispheric and right intrahemispheric functional connectivity in ACC patients as compared to controls. In addition, stronger functional connectivity between left and right temporal areas was associated with better language abilities in the ACC group. In healthy controls, no association between language abilities and connectivity was found. Our results show that ACC is associated not only with less interhemispheric, but also with less right intrahemispheric language network connectivity in line with reduced verbal abilities. The present study, thus, supports the excitatory role of the corpus callosum in functional language network connectivity and language abilities.

Atypical language representation is unfavorable for language abilities following childhood stroke.

Brain plasticity has often been quoted as a reason for the more favorable outcome in childhood stroke compared to adult stroke. We investigated the relationship between language abilities and language localization in childhood stroke. Seventeen children and adolescents with left- or right-sided ischemic stroke and 18 healthy controls were tested with a comprehensive neurolinguistic test battery, and the individual neural representation of language was measured with an fMRI language paradigm. Overall, 12 of 17 stroke patients showed language abilities below average, and five patients exhibited impaired language performance. fMRI revealed increased activity in right hemisphere areas homotopic to left hemisphere language regions. In sum, seven stroke patients revealed atypical, i.e. bilateral or right lateralized language representation. Typical left hemispheric language lateralization was associated with better performance in naming and word fluency, whereas increased involvement of right homologues was accompanied by worse language outcome. In contrast, lesion lateralization or lesion volume did not correlate with language outcome or atypical language lateralization. Thus, atypical language lateralization is unfavorable for language outcome, and right homologues do not have the same cognitive capacity, even in young children.

When two are better than one: Bilateral mesial temporal lobe contributions associated with better vocabulary skills in children and adolescents.

This study considered the involvement of the mesial temporal lobe (MTL) in language and verbal memory functions in healthy children and adolescents. We investigated 30 healthy, right-handed children and adolescents, aged 7-16, with a fMRI language paradigm and a comprehensive cognitive test battery. We found significant MTL activations during language fMRI in all participants; 63% of them had left lateralized MTL activations, 20% exhibited right MTL lateralization, and 17% showed bilateral MTL involvement during the fMRI language paradigm. Group analyses demonstrated a strong negative correlation between the lateralization of MTL activations and language functions. Specifically, children with less lateralized MTL activation showed significantly better vocabulary skills. These findings suggest that the mesial temporal lobes of both hemispheres play an important role in language functioning, even in right-handers. Our results furthermore show that bilateral mesial temporal lobe involvement is advantageous for vocabulary skills in healthy, right-handed children and adolescents.

Weaker semantic language lateralization associated with better semantic language performance in healthy right-handed children.

INTRODUCTION: The relationship between language abilities and language lateralization in the developing brain is important for our understanding of the neural architecture of language development. METHODS: We investigated 35 right-handed children and adolescents aged 7-16 years with a functional magnetic resonance imaging language paradigm and a comprehensive language and verbal memory examination. RESULTS: We found that less lateralized language was significantly correlated with better language performance across areas of the brain and across different language tasks. Less lateralized language in the overall brain was associated with better in-scanner task accuracy on a semantic language decision task and out-of-scanner vocabulary and verbal fluency. Specifically, less lateralized frontal lobe language dominance was associated with better in-scanner task accuracy and out-of-scanner verbal fluency. Furthermore, less lateralized parietal language was associated with better out-of-scanner verbal memory across learning, short- and long-delay trials. In contrast, we did not find any relationship between temporal lobe language laterality and verbal performance. CONCLUSIONS: This study suggests that semantic language performance is better with some involvement of the nondominant hemisphere.

Structural congenital brain disease in congenital heart disease: results from a fetal MRI program.

OBJECTIVE: To identify the type and incidence of fetal brain pathology in fetuses with a prenatal diagnosis of congenital heart disease (CHD). PATIENTS AND METHODS: 67 pregnant women underwent a fetal MR-examinations between 20 and 38 gestational weeks. MR was done on a 1.5 T superconducting system. The type of cardiac malformation was defined by fetal echocardiography. Fetuses with a chromosomal abnormality or an extracardiac anomaly were excluded. RESULTS: Fetal MRI scans in the final study cohort (53 fetuses) yielded normal results in 32 fetuses and a brain abnormality in 21 fetuses. Congenital brain disease (CBD) was found in 39% of the final study cohort of fetuses with CHD. MRI findings were classified into malformations, acquired lesions and widening of the ventricles and/or outer CSF spaces (malformations: 7 fetuses, acquired lesions: 5 fetuses, changes in CSF spaces: 9 fetuses). Asymmetry of the ventricles was the most common finding in the CSF group. CONCLUSIONS: Our data suggest that fetal MRI can be used to characterize structural CBD in CHD. Advanced MRI techniques such as diffusion tensor imaging and proton spectroscopy are tools that, in the future, will certainly shed light on the spectrum of structural and functional CBDs that are associated with CHD.