Understanding the ‘Lexia’ in dyslexia: A multidisciplinary team approach to learning disabilities

The historical roots of the IQ-achievement discrepancy definition of learning disability are discussed as a reference point for explaining why this definition came into being and why it is inadequate for dealing with the variety of learning and developmental disabilities that present in school settings. A proposal is offered and justified for defining learning disabilities on the basis of profiles for multiple developmental domains that affect learning. In this proposal, developmental dyslexia is differentiated from other learning disabilities. Developmental dyslexia is defined as uneven development (dissociation) between word reading and higher-level processes in the functional reading system. Dyslexics may struggle with word reading because of deficits in phonological processes, orthographic-phonological connections, and/or fluency (rate, automaticity, or executive coordination). The need for both national and international classification schemes for defining specific learning and developmental disabilities for the purposes of educational services and research is emphasized. Grant P50 33812-06 from the National Institute of Child Health and Human Development supported preparation of this article.