NEUROBEHAVIORAL DEVELOPMENT--NORMAL, LI & DEAF CHILDREN

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DESCRIPTION (provided by applicant): Our broad goals are to characterize the identity, developmental time courses and relative plasticity (modifiability/vulnerability) of neural systems and subsystems important in language processing and related attentional and sensory skills. In children 2-8 years of age we will acquire event-related brain potentials (ERPs) and, in 6- to 8-year-olds, we will also acquire structural and functional magnetic resonance images (MRI) of the brain to precisely characterize both the timing and the location of neural activations as subjects perform tasks designed to activate specific aspects of sensory and language functions. In normally developing children we will test the hypothesis, based on our previous research, that systems that have longer developmental time courses are more vulnerable and are modifiable during limited (and variable) time periods, whereas systems that develop early are less vulnerable and retain the ability to change throughout life. In younger and older groups of normal children, we will assess the relative modifiability of these systems by language experience by studying children (1) at the beginning and at the end of a school year in classrooms where teachers' speech displays either higher or lower syntactic complexity and lexical diversity and (2) before and after 10 weeks of an intervention program designed to facilitate language growth. We will test the hypothesis that increased language input leads to increases in semantic and attentional skills and related neural systems in both age groups, but will affect the development of grammatical and morphological systems only in the younger age group. In addition, we will characterize these same systems in younger and older language impaired (LI) children to assess different hypotheses about the deficits that give rise to LI, and related hypotheses concerning whether or not and how Fast ForWord (FFW), Grammatical Facilitation (GF) and Narrative-Based (NBLI) interventions impact language in LI children. We will assess the hypothesis that FFW improves rapid auditory processing and auditory attentional skills in all children and that GF and NBLI affect grammatical processing and related neural systems but only in younger children. Since the proposed research will provide evidence about which perceptual and language systems are most altered by environmental input, and the time periods when they are most modifiable, these studies wilt contribute information of practical significance for the development, refinement and evaluation of educational and habilitative programs.