Evaluation of human middle ear function via an acoustic power assessment

Abstract

Measurements of middle ear (ME) acoustic power flow (power reflectance, power absorption, and transmittance) and normalized impedance (acoustic resistance, acoustic reactance, and impedance magnitude) were compared for their utility in clinical applications. Transmittance, a measure of the acoustic power absorbed by the ME, was found to have several important advantages over other measures of acoustic power flow. In addition to its simple and audiologically relevant physical interpretation (absorbed power), the normal transmittance curve has a simple shape that is visually similar to the ME transfer function. The acoustic impedance measures (resistance and reactance) provided important additional information about ME status and supplemented transmittance measurements. Together these measurements can help identify unusual conditions such as eardrum perforations. While this article is largely a review of the development of a commercial power reflectance measurement system, previously unpublished experimental results are presented.

Predictions of middle-ear and passive cochlear mechanics using a finite element model of the pediatric ear

“…The EA level representation in Eq. (11) allows for useful comparisons to other logarithmic measures of hearing function (Allen et al, 2005). The FE analysis ran on a personal computer (Dell Precision T7910, 32 GB memory) using ANSYS 15.0, and the computation time was 18 min, 20 s for all responses at 20 frequencies.…”

“…The EA, umbo and BM displacement level changes provide different views of how the MEE impedes the sound transmission from the ear canal into cochlea. EA is one of power-flow variables that can provide useful information on the status of the ear canal and middle ear (Allen et al, 2005). Unlike EA, which measures the response of the whole TM, umbo displacement is a more direct measure of the dynamic state of the middle ear ossicles and is less influenced by the compliance of the TM (Rosowski et al, 2012), which is a possible explanation of the more correlation of the umbo displacement level loss with the BM loss.…”

“…These measures are used in research and clinical audiology with both adults and young children to differentiate between normal ears and ears with specific middle-ear disorders (Keefe et al, 1993;Feeney et al, 2003;Allen et al, 2005;Beers et al, 2010;Ellison et al, 2012;Hunter et al, 2013). EA is the fraction of incident energy absorbed by the ear at a probe inserted in a mid-canal location.…”

Reflectância de banda larga em indivíduos com artrite reumatoide

“…A OM atua como um transformador de impedância entre o ar, de baixa impedância, do meato e os fluidos, de alta impedância, da cóclea (Margolis e Hunter, 2001, Allen et al, 2005. Como o sistema de transmissão não é perfeito, parte da energia incidente é absorvida no tímpano e parte é refletida de volta no MAE (Stinson, 1990).…”

“…A reflectância de energia (RE) mensura a razão entre a energia refletida e a energia incidente na orelha média. Esta razão vai de zero (quando há transferência completa do som na orelha média) a um ou 100% (quando nenhum som é transferido) (Keefe et al, 1993;Allen et al, 2005). Tal método apresenta algumas vantagens sobre a timpanometria, como: (a) não é necessária a pressurização do MAE; (b) fornece informações sobre uma ampla faixa de frequências; (c) pode ser realizado em poucos segundos (Feeney et al, 2003;Hunter et al, 2008).…”