Beakeasy Audiometry and Clinical Masking

Abstract

Békésy audiometry was performed in 31 patients with unilateral perceptive hearing loss, both in quiet and with 80 dB masking of the unaffected ear. The test tones and masking noise were applied with inserttype receivers. The masking noise was found to increase the separation between “I” and “C” tracings, as well as to cause a highly significant reduction in the tracing amplitude of fixed-frequency “C” tracings at 250 and 1000 cps, and of sweep-frequency “C” tracings at both lower and higher frequencies. In 7 patients, the masking changed an audiogram of Jerger type I to type II, in 7 patients it changed an audiogram of type II to type IV, and in 3 patients it changed a type I to type IV. The relation between the tracing amplitude for “I” and “C” was also changed. It is concluded that no matter what the parameter used in the evaluation, the result is often decisively influenced by the masking delivered to the non-test ear.