Coupled Circuits Model in Objective Audiometry

Abstract

The technique for objective audiometry of human hearing loss based on the formula for the middle ear norm parameter and the principle of sound reflection from the tympanic membrane, as well as the genetic connection of the sound “a” with the auditory system's resonances, is considered. The proposed technique involves determining the dimensionless middle ear parameter using a multi-frequency impedance meter, being equal to one means no loss in the middle ear and the absence of birth defects. The ratio of the equivalent volume at the working frequencies of the probe signal to the equivalent volume at the resonant frequency creates an individual curve of the “audiological zero” with much greater accuracy than the “audiological zero” curve for subjective audiometry obtained by averaging the sensitivity threshold curves of the sufficient number of otologically healthy people. The ability to receive individual thresholds of audibility allows us to evaluate the functional state by determining the norm parameter or individual audibility thresholds for one and the same subject at certain intervals of time. Moreover, based on the analysis of the transient evoked otoacoustic emissions signals (TEOAE) in the outer acoustic meatus, it is shown that TEOAE is a pulsed function of the human ear with successive two maxima at resonant frequencies. It is determined that these frequencies coincide with the most prominent second and third formants of the sound “a”. Additional diagnostic parameters of the state, along with the middle and the inner human's ear are suggested.