Limited retention of information in the graphemic buffer.

This study examined a patient who mainly made letter deletion errors in spelling. It was hypothesized that his errors were due primarily to limited ability to retain information in the graphemic buffer, a structure that holds sequences of abstract letter identities for output. Consistent with this hypothesis, the patient's spelling accuracy declined on long words, but the number of letters he wrote per response was not related to word length. Moreover, by having him write words forward and backward, it was shown that his accuracy within a word depended on which part of the word he tried to output first. These results also ruled out alternative accounts of the patient's spelling deficit based on neglect or damage to lexical representations.