The cochlea actively amplifies sound and emits echoes that reveal inner-ear health

Evidence

Otoacoustic emissions—sounds generated by your own hearing system—are a condition everyone’s flesh is to some degree heir to, simply because the hearing apparatus, from ear to brain, works not only as a receptor but as an amplifier. — George Michelsen Foy, Zero Decibels, 329 (#corroborates, via linked claim)

Otoacoustic emissions (OAEs) are faint sounds that travel from the cochlea back through the middle ear and are measured in the external auditory canal. Since their discovery in the late 1970s by David Kemp ( 1978 ), they have been used in the clinic to evaluate the health of outer hair cells (OHC) and in research to gain scientific insight into cochlear mechanics. Behaviorally they have been shown to predict the pattern of pure-tone quiet thresholds (Long and Tubis 1988 ; Lee and Long 2012 ; Dewey and Dhar 2014 ), auditory frequency selectivity, (Baiduc et al. 2014 ), and loudness perception (Mauermann et al. 2004 ). — Dijk, Pim van, Physiology, Psychoacoustics and…, 5757 (#expands, via linked claim)

Categorization

• XREF: connects to: Healthy ears emit detectable sounds that have become standard newborn hearing tests.; OAEs reveal cochlear function through sounds emitted back into the ear canal; Low-frequency sound can awaken silent inner ears to emit spontaneous tones (+5 more)

Related

• OAEs reveal cochlear function through sounds emitted back into the ear canal (similarity 0.92)
• Cochlear otoacoustic emissions measurably shift behavioral thresholds, selectivity, and loudness (similarity 0.89)
• Loud noise damage can make the cochlea spontaneously generate its own noise (similarity 0.89)
• Otoacoustic emissions non-invasively probe outer hair cell function in humans. (similarity 0.88)
• Otoacoustic emissions are faint sounds generated by the cochlea that predict auditory function (similarity 0.87)
• Tinnitus arises when the cochlea spontaneously generates its own noise (similarity 0.86)
• A normal-sounding ear is internally a sound source audible in the closed canal (similarity 0.85)
• Low-frequency sound can awaken silent inner ears to emit spontaneous tones (similarity 0.85)
• Healthy ears continuously emit faint spontaneous sounds linked to frequency sensitivity (similarity 0.85)
• Otoacoustic emissions originate peripherally before neural encoding begins (similarity 0.85)
• A healthy cochlea emits new frequencies when stimulated by two tones (similarity 0.84)
• Mild hearing loss eliminates otoacoustic emissions but not psychoacoustic efferent measures (similarity 0.84)
• Otoacoustic emission spectra show discrete energy maxima stable across sensation levels (similarity 0.83)
• Missing otoacoustic emissions reveal conductive or cochlear but not retrocochlear defects (similarity 0.83)
• Spontaneous otoacoustic emissions cluster near SFOAE fine-structure maxima but remain undetectable there. (similarity 0.83)

Broader Connections

• OAEs reveal cochlear function through sounds emitted back into the ear canal #corroborates (0.95)
• The human ear itself generates sound as a byproduct of amplifying incoming signals #corroborates (0.90) — George Michelsen Foy, Zero Decibels, 329
• Cochlear otoacoustic emissions measurably shift behavioral thresholds, selectivity, and loudness #expands (0.80) — Dijk, Pim van, Physiology, Psychoacoustics and…, 5757
• Low-frequency sound can awaken silent inner ears to emit spontaneous tones #expands (0.78)
• The hearing system actively filters and modulates sound more than passively receiving it #expands (0.75) — George Michelsen Foy, Zero Decibels, 558
• Tinnitus arises when the cochlea spontaneously generates its own noise #exemplifies (0.72) — David Howard, Jamie Angus, coustics and Psychoacoustics, 664
• Cochlear outer hair cells enable speech amid noise and reverberation #expands (0.72)