低中音型聴力像を示す家族性難聴

FAMILIAL DEAFNESS SHOWING HEARING-PATTERN OF LOW-AND MIDDLE-TONE LOSSES

　Ⅰ．緒言

　感音性難聴の聴力像は通常高音障害型であり，低音性難聴をみることはまれである。この低音性感音性難聴については近年いくつかの論文が発表され，その病態，成因などが論ぜられているが，まだ不明の点も少なくない。

　最近，われわれは家族性難聴の臨床的観察を行なつたが，今回は同一家系内の聴力像の類似性と家族性難聴にしばしば認められた低音ならびに中音障害型の聴力像について若干の考察を加えてみたい。

　A clinical study of low-and middle-tone deafness that involved about 50 % of 60 cases of deafness who were siblings of 30 families affected with familial deafness, is made.

　The individual pattern of deafness occurring in one particular family was amazingly similar to each other.

　Comparative study of these patterns suggested the possibility of further developing into various hearing patterns. The pattern of loss of low-and middle-tones are similar to each other and differ only by being in different stages of the progression of deafness.