Abstract
We report a Japanese patient of non-fluent childhood aphasia who showed difficulty in reading postpositions in a phrase or a sentence. Japanese postpositions are always written in kana characters (syllabary). The patient could name the kana characters when they were presented in isolation. Naming tasks of kana words, as well as of phrases and sentences written in a kanji (morphographs) and kana mixture were administered. He revealed signs of mild deep dyslexia or phonological dyslexia, such as pseudo-homophone, lexicality and word frequency effects in naming kana words, and also parts of speech and imageability effects in naming phrases and sentences written in kanji and kana. When naming ungrammatical phrases with incorrect postpositions, he tended to name them grammatically. These phenomena were thought to result from damage to phonological representation. He repeatedly substituted a postposition into others as if he were searching for the right answer. The number of each incorrectly produced postposition significantly correlated with its frequency, suggesting that phonological representation of a postposition with higher frequency is more efficiently activated than that with lower frequency.
