Estimation of Middle Ear Characteristics by an Innovative Pressure-Less Acoustic Immittance (PLAI™) Device

Tympanometry is a gold standard method for the evaluation of hearing function, allowing the identification of pathological alterations of the outer and middle ear by a non-invasive approach. However, in order to make the measurement it is necessary to alter the pressure of the outer ear, which limits the use of the technique for newborns and people with tympanic perforation. To overcome this problem, a complete pressure less technique (PLAI™) was proposed. This paper aims to present the statistically significant correlations between the resonance frequency measured with PLAI™ and the estimated volume and compliance obtained through tympanometry in both healthy subjects and patients affected by Otitis Media with Effusion (OME). The tests, conducted on 57 adult subjects, indicated a significant linear relation between the volume measured with tympanometry and the resonance frequency obtained with PLAI™ that could be used to calculate a value of volume comparable with the gold standard. Moreover, an inversely proportional relation between the compliance from tympanometry and the resonance frequency from PLAI™ was found, even if affected by several outliers, which hinder a practical use of this specific relation. These two preliminary findings show that it is possible to use this new technique as a preliminary test in subjects deemed to be at risk with tympanometry, eliminating the drawbacks related to the pressure changes but offering a comparable measurement of volume and possible future chances of research.