Assessment of Conductive Dysfunction: Wideband Acoustic Immittance

Abstract

The conductive mechanism plays an important role in our hearing: the first stage of signal processing in the auditory system. While it consists of the ear canal, the crucial portion is the middle ear system, which transforms airborne sound into mechanical vibration and helps improve sound transmission into the fluid-filled inner ear. Hearing loss due to dysfunction of the middle ear system may be threatening to the quality of life for humans. For example, conductive hearing loss may significantly impact normal speech and language development of children. Assessment of middle ear dysfunction is essential for audiological diagnosis of hearing loss and differential diagnosis of ear diseases. For instance, middle ear dysfunction may cloud outcomes of newborn hearing screening. Acoustic immittance is the current clinical technique for assessment of middle ear dysfunction. The major procedures include tympanometry and acoustic reflex test. In these procedures, a single-frequency probe tone (e.g., 226 Hz and 1000 Hz) is used to estimate the acoustic impudence/admittance of the middle ear. Although they have been a clinical routine in audiology since 1970s, value of these procedures in assessment of conductive dysfunction has been limited.