Changes in the distribution of language function in the brain have been documented from infancy through adulthood. Even macroscopic measures of language lateralization reflect a dynamic process of language development. In this review, we summarize a series of functional MRI studies of language skills in children ages of five to 18 years, both typically-developing children and children with brain injuries or neurological disorders that occur at different developmental stages with different degrees of severity. These studies used a battery of fMRI-compatible language tasks designed to tap sentential and lexical language skills that develop early and later in childhood. In typically-developing children, lateralization changes with age are associated with language skills that have a protracted period of development, reflecting the developmental process of skill acquisition rather than general maturation of the brain. Normative data, across the developmental period, acts as a reference for disentangling developmental patterns in brain activation from changes due to developmental or acquired abnormalities. This review emphasizes the importance of considering age and child development in neuroimaging studies of language.

No abstract

Summary:Purpose: The goal of this study was to compare language lateralization between pediatric epilepsy patients and healthy children.Methods: Two groups of subjects were evaluated with functional magnetic resonance imaging (f MRI) by using a silent verb-generation task. The first group included 18 pediatric epilepsy patients, whereas the control group consisted of 18 age/gender/handedness-matched healthy subjects.Results: A significant difference in hemispheric lateralization index (LI) was found between children with epilepsy (mean LI = −0.038) and the age/gender/handedness-matched healthy control subjects (mean LI = 0.257; t = 6.490, p < 0.0001). A dramatic difference also was observed in the percentage of children with epilepsy (77.78%) who had atypical LI (righthemispheric or bilateral, LI < 0.1) when compared with the age/gender/handedness-matched group (11.11%; χ 2 = 16.02, p < 0.001). A linear regression analysis showed a trend toward increasing language lateralization with age in healthy controls (R 2 = 0.152; p = 0.108). This association was not observed in pediatric epilepsy subjects (R 2 = 0.004, p = 0.80). A significant association between language LI and epilepsy duration also was found (R 2 = 0.234, p < 0.05). Conclusions: This study shows that epilepsy during childhood is associated with neuroplasticity and reorganization of language function.

Adolescence is a complex transitional period in human development, composing physical maturation, cognitive and social behavioral changes. The objective of this study is to investigate sex differences in white matter development and the associations between intelligence and white matter microstructure in the adolescent brain using diffusion tensor imaging (DTI) and tract-based spatial statistics (TBSS). In a cohort of 16 typically-developing adolescents aged 13 to 17 years, longitudinal DTI data were recorded from each subject at two time points that were one year apart. We used TBSS to analyze the diffusion indices including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Our results suggest that boys (13–18 years) continued to demonstrate white matter maturation, whereas girls appeared to reach mature levels earlier. In addition, we identified significant positive correlations between FA and full-scale intelligence quotient (IQ) in the right inferior fronto-occipital fasciculus when both sexes were looked at together. Only girls showed significant positive correlations between FA and verbal IQ in the left cortico-spinal tract and superior longitudinal fasciculus. The preliminary evidence presented in this study supports that boys and girls have different developmental trajectories in white matter microstructure.