CLUES TO THE COGNITIVE ORGANIZATION OF READING AND WRITING FROM DEVELOPMENTAL HYPERLEXIA

Controversies regarding the organization of the cognitive systems used for processing written language were investigated in a case study of a mentally retarded hyperlexic child. Despite severe impairments in se mantic processing, this child demonstrated intact phonological and ort hographic processing. Detailed assessments of his nonword reading abil ities provided support for the hypothesis that phonological processing of written words was accomplished by using lexical representations in stead of applying nonlexical grapheme-phoneme transcoding rules. Longi tudinal investigation of the hyperlexic child's development of writing supports the notion that reading and spelling rely on common mental r epresentations rather than separate input and output mental lexicons.