低音障害型突発難聴

Acute Sensorineural Hearing Loss in Low Frequencies

　I．はじめに

　原因不明で比較的急速に難聴が起こるという点ではいわゆる突発性難聴の範疇に入るものであるが，その聴力障害が低音部に限られ，しかも程度が軽いという点で，一般の突発性難聴とは異質のものが疑われる疾患がある。この種の疾患の存在については，既に多くの臨床医家の認めるところであるが，症例をまとめて検討した報告は少ないように思う。

　筆者は，そのような難聴症例39例について，自覚症状，難聴の経過，予後を検討した結果，本難聴が一つの特異な疾患群とも考えられることを述べ，さらにその病因，障害部位，治療について若干の考察を加えた。

　Investigations on 39 cases of sensorineural hearing loss in low frequencies revealed that the hearing impairment of these cases is considered as one type of the disease itself, though it belongs to sudden deafness in large.

　Clinical features of the hearing impairment were as followes :

　1) Obscure origin.

　2) Relative acute onset.

　3) Females were more frequently affected.

　4) Tinnitus, sensation of ear obstruction andautophonia were very common complaints.

　5) Sensorineural hearing loss was slight or moderate, limitted to the low frequency range.

　6) In most cases, hearing loss was recovered completely in a short period of time.

　This type of hearing impairment is thought tobe caused by latent viral infection of the cochlea or acoustic nerve. Though the hearing impairment of this type can be recovered spontaneously, the treatment applied to sudden deafness seems to be effective to quicken the recovery.