Wideband tympanometry and absorbance measurements in otosclerotic ears

Abstract

Objectives This study aimed to assess absorbance using a thorough analysis of individual points of its plot in ears with intraoperatively confirmed otosclerosis. To the best of our knowledge, until recently no analyses have been performed that concerned the shape of an absorbance plot and a detailed analysis of its individual points. This study is the first to undertake such an issue. Methods A total of 77 otosclerotic ears were included in the study. Pure tone audiometry, low frequency tympanometry, and wide band tympanometry including absorbance were performed preoperatively. The average patients’ age in the group was 43.49 years (standard deviation = 10.44). Individual points of absorbance plot were thoroughly analyzed. Parameters were analyzed, such as resonance frequency; number of peaks; maximum absorbance (Height); and plot Width at the following Heights: 1/3, 1/2, and 2/3 (Width1/3, Width1/2, Width2/3, respectively), as well as associated absorbance parameters and frequencies. Results Data analysis revealed five different types of absorbance plots. Numerous statistically significant differences regarding the parameters of individual points of the plots were found among the distinguished types. Conclusions There are five types of absorbance plots in otosclerotic ears: type I, characterized by two distinct peaks, closely resembling normal ear absorbance plot; type II with a single distinct peak reaching high values of absorbance; type III with reduced absorbance for frequencies <2000 Hz; type IV with reduced absorbance for all frequencies; and type V with reduced absorbance for frequencies >2000 Hz. Absorbance measurements may play an important role in the diagnostics of otosclerosis; however, further research is necessary in this area. Levels of Evidence 4 Laryngoscope, 129:E365–E376, 2019

Analysing wideband absorbance immittance in normal and ears with otitis media with effusion using machine learning

“…The multidimensional graphs obtained from WAI enable the clinician to better understand the dynamic characteristics of the middle ear by recognizing specific tympanometric patterns associated with middle ear pathologic change. Niemczyk et al 12 investigated WAI patterns in ears with intraoperatively confirmed otosclerosis by analysing resonance frequency, and number of peaks with detailed descriptions in terms of height and width. Although the patterns were statistically significantly different and provided important diagnostic information in terms of otosclerotic status, this approach appears less helpful clinically for the purpose of differential diagnosis as the absorbance patterns overlap with absorbance graphs found in the normal ear condition and other middle ear disorders.…”

Measurement of Wideband Absorbance as a Test for Otosclerosis

“…Many investigations have confirmed that absorbance in otosclerotic ears is decreased compared to normal-hearing ears, especially in the low-frequency range [ 1 , 14 , 19 , 20 , 21 ]. The decrease is due to increased stiffness of the vibrating system which in turn gives rise to a decrease in low-frequency acoustic susceptance, and consequently an increase in reflection coefficient.…”

Wideband Acoustic Absorbance in Otosclerosis: Does Stapedotomy Restore Normal Tympanic Cavity Function?*

“…After stapedotomy, the stiffness associated with otosclerosis is reduced, but compliance of the tympano-ossicular system is increased compared with normal ears, making resonant frequency even lower than normal. 15 21 24 25 27…”

“…Many studies have shown reduced absorbance, or increased reflectance, in otosclerotic ears, 14 15 16 17 18 19 particularly in the low frequency band. This reduction in absorbance occurs due to increased stiffness in the system, which leads to a decreased acoustic sensitivity to low frequencies and, consequently, increased reflection.…”