SPATIALLY SPECIFIC DEFICITS IN PROCESSING GRAPHEMIC REPRESENTATIONS IN READING AND WRITING

We report the performance of two brain-damaged subjects, HE and ML, wh ose spelling performance is characterized by selective impairment in p rocessing the side of words contralateral to their brain damage. A str iking feature of these patients' performance was the fact that their s pelling errors in all tasks-written naming, written and oral spelling, and delayed copy transcription-almost exclusively concerned the right half of words (in the case of HE) or the left half of words (in the c ase of ML), regardless of length of the target response. These pattern s of performance are interpreted as indicating damage at the level of the grapheme description computed in all spelling tasks. We also discu ss the additional observations that HE tended to complete words with n onrandom letter sequences in misspelling the final half of the word an d that ML tended to preserve the initial letter of the word fin forwar d but not backward spelling) even when she made errors on other letter s in the initial half of the word. Finally, the relationship between t hese spatially specific impairments of reading and writing and their r elationship to spatially specific deficits in non-lexical tasks is rev iewed. (C) 1995 Academic Press, Inc.