Training grapheme to phoneme conversion in patients with oral reading and naming deficits: A model-based approach

A model-based treatment focused on improving grapheme to phoneme conversion as well as phoneme to grapheme conversion was implemented to train oral reading skills in two patients with severe oral reading and naming deficits. Initial assessment based on current cognitive neuropsychological models of naming indicated a deficit in the phonological output lexicon and in grapheme to phoneme conversion. Using a single subject experimental design across subjects, the effects of treatment were evaluated by periodic probing of both trained and untrained regular words across lexical tasks: oral reading, oral naming, written naming, and writing to dictation. Results indicated successful acquisition of trained reading targets for both patients, as well as generalisation to untrained reading items, oral and written naming of trained items, and writing to dictation of trained and untrained items. Irregular words probed across the four lexical tasks did not demonstrate any improvement, as the trained grapheme to phoneme conversion skills were unsuccessful when applied to irregular words. The present experiment provides evidence for incorporating cognitive neuropsychological models in aiding the development of appropriate treatment protocols, and demonstrates the importance of rule-based learning, rather than compensatory strategies, in maximising the effects of generalisation.