ウェルニッケ失語からの回復経過において音韻性失名詞の臨床像を呈した1例

A clinical presentation of phonological anomia during recovery from Wernicke's aphasia

　音韻性失名詞は臨床で経験することは稀だが，確立された症候概念であり，近年では様々な書籍で散見される．その1例に対し，発症からの経過，特に呼称について詳細な分析を行った．症例は，発症2か月では理解力が低下しており，呼称では語性錯語・音韻性錯語が出現し，ウェルニッケ失語に該当した．発症8か月では理解力が改善し，喚語困難が中核症状として残存した．復唱は良好だが，呼称時のみに音韻性錯語や音断片などの音韻性の誤りが多く出現し，音韻性失名詞に近い病態となった．先行研究との比較検討を行い，他の失語型から音韻性失名詞に緩徐に移行していくタイプの存在が示唆された．また，発症から経過の中で理解が改善を示すこと，呼称成績そのものより錯語の内容が変化していく傾向がみられた．経過を踏まえると障害メカニズムが必ず一致するとは限らず，音韻性失名詞の中でも多様性があることが示唆された．

　Phonological anomia is rarely seen in clinical practice, but it is an established disease concept occasionally encountered in various writings of recent years. We conducted a detailed analysis of the course from onset, particularly with regard to oral naming, in one patient with phonological anomia. At two months after onset the patient had decreased comprehension and verbal and phonological paraphasia appeared in oral naming;these findings corresponded to Wernicke's aphasia. The patient's comprehension had improved at eight months with word finding difficulty remaining as a core symptom. Repetition was good, but phonological paraphasia, phonological fragments, and other phonological errors often occurred only in oral naming and the condition came to closely approximate phonological anomia. A comparison with previous studies suggested the existence of a subtype in which there is a gradual transition to phonological anomia from other aphasia types. In this case, during the course after onset, comprehension improved but in oral naming, changes in the content of the paraphasia were observed without visible increase in the correct number of responses. Consideration of the course suggests that the mechanism of the disorder is not necessarily the same in all cases and that there is some diversity among phonological anomia.