Developmental relationships between dyslexia and specific language impairment. (360G-Wellcome-082036_Z_07_Z)

This longitudinal study will follow the development from 3-7 years, of children at family-risk of dyslexia, children with SLI, and controls. It will document the frequency with which children from these groups experience literacy difficulties, the nature of their reading problems and how these relate to underlying language skills. It will address the overlap between dyslexia and SLI at different points in development, identify endophenotypes of dyslexia and assess the extent to which indivi dual, family and environmental factors play a role in determining outcome. The research will use assess two causal hypotheses: 1. that an underlying deficit in auditory processing causes deficits in speech perception, which in turn lead to the phonological processing impairments that underlie reading problems in dyslexia and SLI. 2. that the phonological processing impairments and other language problems that are central to dyslexia and SLI cannot be traced to underlying auditory or speec h perceptual problems but instead reflect problems in more central language or other cognitive systems. The study will also assess the mediators of response to reading intervention in these groups.