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Abstract:
A case study is presented that provides evidence for separate
graphemic lexicons involved in reading and spelling. Patient ML
showed a phonological dyslexic pattern in reading, with near normal
word reading but severely impaired nonword reading. In contrast,
his spelling was very impaired for both words and nonwords.
Extensive testing of reading and spelling indicated that he could
access lexical graphemic representations in reading but not in
spelling. An alternative account of these findings is that there is
one graphemic lexicon with separate input and output connections to
semantics and ML has a disruption on the output side. To test
between the two possibilities, a copying task was conducted with
three conditions ñ direct copying, and copying after short
and longer delays. Words that ML could or could not write correctly
to dictation were used. The single lexicon approach would predict
that MLís accuracy in copying should be unaffected by
whether or not he could spell the words correctly, since persisting
activation in the single lexicon could be used to reproduce the
target word even in the delay condition. However, in the delayed
(but not direct copy) condition, ML showed greater difficulty in
reproducing the words he could not write. The results thus suggest
that ML had to access a different graphemic lexicon in the delayed
condition ñ supporting the separate graphemic lexicons
view.
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