難治性低音障害型感音難聴の臨床—治療と病因を中心として

Severe Low-Tone Sensorineural Hearing Loss:Therapeutic Effectiveness and Etiology

　はじめに

　低音域に発症する感音難聴の存在は古くから知られ，数多くの報告がされてきた。めまいをともなわず，反復する聴力障害を呈することも多く，蝸牛型（不全型）メニエール病などと呼ばれることもある。一般に予後は良好で，自然寛解例も多い。しかし，長期観察下では，再発を繰り返したり，メニエール病に移行したり，あらゆる治療に抵抗を示す難治例も少なくない^1）。

　今回はとくに，これら難治例についての治療，病因について検討したので報告する。

Low-tone sensorineural hearing loss was de-scribed many years ago and many cases have been reported. These patients convalesce satisfactorily and several cases show spontaneous improvement, but on long-term observation, there are recurrence and severe cases that resist to therapy are numer-ous.

We studied the classification, therapy and cause of severe cases. Severe low-tone sensorineural hear-ing loss was classified into five types and treated with STT (steroid targeting therapy). STT is transtympanic injection of steroid to the patients with recurrence or intractable severe cases. Such therapy had some effect. The improvement rate was 45.8 %.

The cause of low-tone sensorineural hearing loss was suggested to be vascular disorders of the stria vascularis.