Lexical influences in graphemic buffer disorder.

We report the case of patient BH, who misspelled about half of the words she attempted and showed the characteristic features of "graphemic buffer disorder" (an effect of letter length on spelling accuracy, errors involving the substitution, omission, addition, and movement of letters that affect the middles more than the ends of words). Speech comprehension and production were good. Reading of words was, at most, only mildly impaired, though reading of nonwords was more affected. Words were spelled more accurately than nonwords, and BH's ability to spell words correctly was influenced by their imageability, age of acquisition, frequency, and number of orthographic neighbours (N). The effect of length was much reduced once these factors (especially N) were controlled. BH's spelling pattern is discussed in terms of top-down lexical influences on the graphemic buffer. We argue that such effects may be more widespread than has previously been acknowledged.