不快感発現音響強度閾(Uncomfortable loudness level)

抄録

The author studied on the uncomfortable loudness level (ULL) of the normal and conductive or sensory deafness ears. The results are as follows:
The ULL of the normal ear is about 75db. That of the deafened ear is closely related with the loudness growth, but also influenced by the mechanism of sensory nerves in the external aucitory canal and the middle ear, or psychologic factors. However, these two latter factors have not so st-rong influence that they change the essence of the ULL.
The ULL of the ear with sensory deafness agrees with the recruitment phenomenon, and therefore. the ULL can be used to a certain degree for the differential diagnosis of deafness.
When the ULL is above 85-95db by sensation level, and the difference between the ULL and the minimum threshold of audibility (the autllor called "comfortable area") is above 50-60db, the-deafness is mostly conductive deafness, and when the level or area is below those values sensory deafness is suspected.