Selective impairment of On-reading (Chinese-style pronunciation) in alexia with agraphia for kanji due to subcortical hemorrhage in the left posterior middle temporal gyrus.

We report a patient with alexia with agraphia for kanji after hemorrhage in the left posterior middle temporal gyrus. The results of single-character kanji reading and two-character on- (Chinese-style pronunciation), kun- (native Japanese pronunciation), and Jukujikun (irregular kun-) reading word tests revealed that the patient could not read kanji characters with on-reading but read the characters with kun-reading. We consider that this on-reading alexia was caused by disconnection between the posterior inferior temporal cortex (orthographic lexicon) and the posterior superior temporal gyrus (phonological lexicon), and preserved kun- and Jukujikun-reading was realized by bypassing the orthography-to-phonology route by the semantic route.