Shin-Ichi IZUMI, Fumiko ANZAKI, Akira ISHIDA

Department of Rehabilitation Medicine, Tokai University School of Medicine

(Received 9 July 1998; accepted 7 May 1999)

Abstract: We investigated speech errors in Wernicke's aphasia to examine whether and what kind of errors in lexical retrieval are critical in the speech production deficit of Wernicke's aphasia in the Japanese language system. Three right-handed male patients with Wernicke's aphasia due to cerebral infarction were graded as having mild, moderate, or severe aphasia according to the Standard Language Test of Aphasia, Token Test, and Phonetic Discrimination Test. Production of words with 1 to 6 syllables was tested by having patients name objects drawn on a card, and having them repeat or read aloud words written in Kana characters. Production of words with 1 to 4 syllables was tested by having patients read aloud words written in Kanji characters. Speech errors were classified to semantic paraphasia, verbal paraphasia not semantically related to the target word, phonological paraphasia, neologism, conduites d'approche, errors of one-syllable words. Phonological paraphasias were classified as addition, omission, dislocation, or substitution. Errors of dislocation and substitution were classified as vowel or consonant errors. The more severe the aphasia, the higher was the rate of consonant errors. We suggest that impairments in consonant retrieval is critical in the speech production deficit of Wernicke's aphasia in Japanese-speaking patients.

Key words: aphasia, paraphasia, Wernicke area, phonological error,Japanese language