Impedance audiometry and otoadmittance meter are used more often recently f or evaluation of the ossicular chain, patency of the eustachian tube and middle ear pathology. They are called either tympanometry or impedancemetry. Reported here are the results of studies on normal and diseased ears done at Toho Medical School with the use of Type 1720 otoadmittance meter made by Grason-Stadler.
A total of 102 ears, consisting of 64 normal and 38 hard of hearing ears, ranging 7 to 18 years in age, were tested.
Tympanograms obtained can be divided into 6 types. Most of the 64 normal ears belonged to Type I, while most of the 12 ears with conductive loss to type 2 and most of the 26 ears with sensorineural loss to type 4.
The results of our test reconfirmed the data reported previously on the hard of hearing ears. However, they showed several interesting findings in normal ears, which will be discussed in the paper.
