Atoacoustic emission is a term used to describe the sounds emitted by the hair cells in the inner ear in response to sound stimuli. The correct spelling of atoacoustic emission can be explained using the International Phonetic Alphabet (IPA) as [ætəʊəˈkuːstɪk ɪˈmɪʃən]. This phonetic transcription indicates that the first syllable is pronounced with the short vowel sound æ, followed by a diphthong (combination of two vowel sounds) represented by əʊ. The second word is stressed on the second syllable, with the vowel sound ʊ pronounced as "oo".
Atoacoustic emission refers to the sound produced by the cochlea in response to acoustic stimulation. Specifically, it is a low-intensity, acoustic signal generated by the outer hair cells of the inner ear. These emissions are generally measured by a sensitive microphone placed in the external ear canal.
Atoacoustic emissions are considered to be a valuable tool in audiological and otological research and diagnostics. They serve as an indirect measure of the integrity and function of the auditory system. The emissions are characterized by a frequency range between 500 Hz and 20 kHz and can be detected even in individuals with normal hearing. However, the signal's amplitude and frequency composition can provide insights into the presence and nature of hearing loss or abnormalities in different parts of the auditory system.
There are various types of atoacoustic emissions, including spontaneous emissions, which occur without acoustic stimulation, and evoked emissions, which are generated in response to external sounds. Evoked emissions are further classified into transient evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) among others. Each type has unique characteristics and can provide different information about the auditory system.
Overall, atoacoustic emissions offer a non-invasive and objective method to assess the inner ear's function, aiding in the diagnosis of hearing impairments and monitoring the effectiveness of interventions, such as the fitting of hearing aids or cochlear implants.
The word "otoacoustic emission" (not "atoacoustic emission") originates from the Greek roots "oto-" (ὠτός) meaning "ear" and "acoustic" (ἠχώ) meaning "sound". "Otoacoustic" combines these roots to describe a sound originating from the ear.