Impairment in writing, but not reading, morphologically complex words.

We report a patient, FP, with phonological dyslexia who is impaired in writing affixed words to dictation, but demonstrates no such deficit when reading affixed words. Moreover, she was much more impaired in the writing of regularly inflected words (e.g., "walked") as compared to irregularly inflected words (e.g., "ran") and derived words (e.g., "walker"). These findings indicate that FP's deficit was morphologically based and are consistent with accounts that assume that morphologically complex words are decomposed during lexical processing. The data also suggest that the lexical representations mediating reading and writing are, at least in part, dissociable.