Wideband Acoustic Immittance: Normative Study and Test–Retest Reliability of Tympanometric Measurements in Adults

Abstract

Purpose The purpose of this study was to present normative data of tympanometric measurements of wideband acoustic immittance and to characterize wideband tympanograms. Method Data were collected in 84 young adults with strictly defined normal hearing and middle ear status. Energy absorbance (EA) was measured using clicks for 1/12–octave frequencies (0.236 to 8 kHz), with the ear canal air pressure systematically varied (+200 to −300 daPa). In 40 ears, 7 consecutive trials and a trial of clinical 226-Hz acoustic admittance ( Y a ) tympanometry followed. A cavity test was also conducted. Results From the wideband EA tympanogram, several EA spectrums and EA tympanograms were derived. Descriptive statistics were performed, and population parameters were estimated. The immediate test–retest reliability was excellent. Effects of ear canal air pressure on EA were examined comprehensively. Differences in EA between tympanometric and ambient-pressure measurements were significant. Single-frequency EA tympanograms exemplified for half-octave frequencies were contrasted. The bandpass EA tympanogram, 0.236- and 1-kHz EA and Y a tympanograms, and 226-Hz Y a tympanogram were compared in 9 variables. Conclusions This study established a database of wideband tympanograms in healthy adults. The data analyses will promote our understanding of the middle ear transfer function. These data will serve as a reference for further studies in clinical populations.