On The Use of Hearing-Aid Type Earphones in Clinical Audiometry

Abstract

In a preceding article (König, 1962) it was demonstrated that the most important factors which actually limit the range of application of the different procedures normally employed in clinical audiometry are the transcranial and transtemporal leakages. The observations reported here are intended to concretize our previous theoretical considerations and to show how the use of hearing-aid type earphones may enhance the accuracy of audiometric measurements. In order to evidence the advantages of such earphones in a striking manner, the author gives a typical example of severe bilateral middle ear deafness where neither the air-conduction curves nor the bone-conduction curves could be determined correctly by means of ordinary receivers of commercially available audiometers, whereas by using hearing-aid type earphones the audiometrist was able to establish a more strictly accurate audiogram. In contrast to the maximum bone-air gap generally observed in the different audiology centres, transtympanic transmission losses as high as 90 db were recorded at certain frequencies.