Communication impairments in children: causes, correlates and outcomes. (360G-Wellcome-053335_Z_98_C)

Children with specific language impairment (SLI) fail to develop language at the normal rate, for no apparent cause. This programme is concerned with the causes of SLI, both in terms of underlying cognitive processes, and in terms of etiology. One theory maintains that a basic problem in auditory perception is at the root of SLI, with language difficulties as a secondary consequence. The ways in which auditory perceptual problems can affect language learning will be explored by assessing language development in children with mild hearing losses, and by modelling the effects of degraded auditory input on language learning in a computer simulation. Auditory discrimination will also be investigated directly in children with SLI, by recording electrical brain responses to different sounds; the effects of training auditory discrimination will also be examined. At the etiological level, twin studies reveal significant heritability for SLI, but results vary depending on how the phenotype is defined. This study will consider which aspects of SLI are most heritable, and will look for environmental correlates of non-heritable deficits. In addition, heterogeneity of SLI will be explored by studies aimed at pinpointing the nature of "pragmatic language impairment", which is diagnosed when a child who can produce complex language fails to use it appropriately.