抄録
Following ABR measurement, tympanogram was recorded and analysed in infants and children during sleep induced by sedatives. In this study, the middle ear cavity pressure in most of the subjects was increased in course of sleep, and we called this type as type +A tympanogram (positive pressure tympanogram).
The acoustic reflex threshold on type +A tympanogram was compared with that on type A.
The results were as follows.
There was no significant difference in threshold between both acoustic reflex of normal hearing subjects.
When ear canal pressure was not matched to the point of maximal compliance on tympanogram, acoustic reflex thereshold was elevated or absent.
Therfore, on measurement of acoustic reflex threshold, we emphasized that ear canal pressure must be matched to the point of maximal compliance of tympanogram.
