The threshold of the evoked otoacoustic emissions-a relationship to the spontaneous otoacoustic emissions

Abstract

The threshold of the evoked otoacoustic emissions (EOAE) of normal hearing subjects was measured by using otodynamic analyzer ILO88. The subjects consisted of normal hearing individuals, tinnitus without hearing loss, low tone deafness and hyperacusis. The hearing level of them was within normal limit at the measurement. The results obtained were as follows.
1. There was no difference in threshold of the EOAE between normal individual group and other subjects. But significant difference existed among the individuals.
2. The interaural difference of the threshold of EOAE might be more appropriate for the clinical use than the threshold itself.
3. Because of the phase lock effect to the spontaneous otoacoustic emissions (SOAE) by the stimulative tones, the threshold of the ears with SOAE was smaller than that of the ears without SOAE. (54.6 vs 65.3 dB SPL)
4. The further informations of the inner ear might be obtained by the analysis of frequency spectra of EOAE.