acous-, acou-, acouo-, acoustico-, acouto-, acousti-, -acousia, -acousis, -acoustical, acu-, -acusis-, -acusia
(Greek: akoustikos, to hear, hearing; to listen, listening)
The human ear serves as both a detector and a generator of sound. Tiny hair cells in the inner ear convert incoming acoustic vibrations into nerve signals, but as the cells move in response to sound waves, they themselves produce faint sounds, which are known as otoacoustic emissions.
By listening to these feeble signals, researchers can study in remarkable detail how the inner ear works. Now, detection of these emissions shows promise as a means of evaluating a wide range of common hearing problems involving damage to hair cells.
The sound source generates either a click or a tone, and the microphone picks up the resulting ear-generated sound. In an ear with normal hearing, the faint output sound is nearly identical to the input sound.
This type of test may prove particularly valuable because many hearing difficulties involve damage to hair cells. Such damage can be caused by exposure to prolonged or excessively loud noises, various drugs, or bacterial and viral infections.
Symptoms of presbycusis are gradual hearing loss and tinnitus.
The normal process of growing older produces changes in the cochlea and the cochlear nerves and, in other words, damage in the inner ear, and results in permanent sensorineural hearing loss.
Presbycusis most often occurs in both ears and, because the loss of hearing is so gradual, people with presbycusis may not realize that their hearing is diminishing.
Presbycusis is common, affecting a third of the people between 65 and 75 years and up to a half of the people 75 and over.
The only treatment for presbycusis is the wearing of hearing aids which can be worn in the ears or behind the ears.
Other visual communicative techniques, such as lipreading or watching facial expressions, are also helpful in coping with hearing loss.
The poor acoustics of the auditorium resulted in the symphony conductor's concern that she might be experiencing pseudoacousma.