fMRI Study of Normal Language Development in Children

2005 Abstract

This proposal is a competitive renewal of a five-year project to study child language development using fMRI. During the first five years of this project, we have successfully recruited and scanned more than 300 normal children ages 5 to 18, and have mapped the distribution of specific language functions in the brain throughout normal development using functional MRI methods. In addition, high-resolution 3D anatomical images and diffusion tensor image (DTI) data has been acquired from these children and we have begun to reveal important correlations between gray and white matter distributions and developmental parameters such as age and IQ. Our results thus far have provided considerable insight about the neural substrates of both normal language development and disorders that disrupt language in pediatric populations; including stroke. The goals of the original proposal have largely been completed and our results have been extensively published and made available to many other laboratories in the form of normative pediatric brain image templates. Normative data from the four fMRI language paradigms we have developed is now used as a reference in studies of a wide range of neurological disorders in children both at our institution and several others worldwide.

In this proposal we will utilize our large normative fMRI language database as a frame of reference for understanding the neuroplasticity and reorganization of language in the brain developing abnormally under the influence of focal onset epilepsy, that begins during childhood. Our original study of normal language development was motivated by a realization that language lateralization in children with epilepsy is more variable and bilateral than expected. Now we propose to investigate childhood epilepsy as a model for chronic brain injury. Using the fMRI language paradigms we have developed and studied extensively in normally developing children, we aim to elucidate the subtle perturbations in language localization and lateralization associated with focal onset epilepsy. We will begin this study by performing fMRI of later developing language skills in children age 9-17 years, who have been followed since their first seizure and have developed partial onset epilepsy within 3 years from the initial seizure. If evidence of reorganization of language is found in this group of (n=50) children, we will then determine when functional reorganization begins by using fMRI to investigate language patterns in a group of (n=50) children immediately after the first seizure; occurring between 6-14 years. This bifurcated longitudinal study design using fMRI and reference to our normative data on language development will allow us to test hypotheses relating to the timing of language reorganization in the developing brain with focal onset epilepsy.