"Blocking" lexical competitors in severe global agraphia: a treatment of reading and spelling

Severe global agraphia in Patient MM is analyzed via anagram spelling. Errors in word spelling reflect conflict among lexical competitors and "blocking" of semantic errors by sublexical and lexical cues. Lexical graphemic competition predominates in the context of MM's nearly absent sublexical transcoding of phonemes into graphemes. His orthographic lexicon is severely impaired, resulting in poor activation of lexemes and impaired activation and inhibition of the grapheme level in spelling. In MM's multiple revisions of spelling errors, graphemes from more than one lexical competitor persist in an active state simultaneously. Experimental treatment addressed MM's impaired sublexical reading and spelling, and facilitated sentence spelling through functional computer tasks. Spelling treatment resulted in evolution of MM's global agraphia to surface agraphia. MM's spelling performance supports the claim that lexical and sublexical processes interact during normal spelling, and shows that severe global agraphia is amenable to treatment.