SEMANTIC MEMORY IMPAIRMENT DOES NOT IMPACT ON PHONOLOGICAL AND ORTHOGRAPHIC PROCESSING IN A CASE OF DEVELOPMENTAL HYPERLEXIA

Recent evidence from patients with progressive language disorders and dementia has been used to suggest that phonological and orthographic p rocessing depend on intact semantic memory. These claims challenge the traditional view that there are functionally separate modules in the language system. The effect of a severe, but nonprogressive, semantic impairment on phonological and orthographic processing was evaluated i n LA, a mentally retarded child with hyperlexia. Knowledge of a word's meaning did not affect LA's word repetition, a measure of phonologica l processing, or his acquisition and retention of orthographic pattern s for writing to dictation low-frequency words with exceptional spelli ngs. These findings support the assertion that both orthographic and p honological whole-word representations can be acquired, stored, and re trieved in the absence of a functional link to semantic memory. (C) 19 97 Academic Press