acous-, acou-, acouo-, acoustico-, acouto-, acousti-, -acousia, -acousis, -acoustical, acu-, -acusis-, -acusia +

Subjective sensations of hearing that originates within or near the ear.

The apparent increase in auditory acuity of a deaf person to conversation in noisy surroundings due to his companion unconsciously raising his voice.

A hearing impairment of a conductive (transfer of sound waves in the ears) or neurosensory nature; partial deafness.

1. Abnormally acute (sharp and loud) hearing, sometimes resulting in pain even when only moderately loud sounds are in the area of the subject; formerly, hyperacousia.
2. Increased sharpness of hearing or a condition that exists when sounds are perceived as unduly loud.

Slightly diminished auditory sensitivity, with the hearing threshold levels above the normal limit so that impairment is measurable in decibels.

1. Applied to a curve passing through those points (in a theater, concert-room, etc.) at which a speaker or performer may be heard equally well.
2. A reference to the equal intensity of sound.
3. In seismology, applied to a line (imaginary or on a map) connecting places where an equal percentage of observers heard the sound of an earthquake.

An instrument used to magnify small sounds so they are audible.

Hypersensitiveness of the organ of hearing (the ears) so that noises actually cause pain.

In physics, an effect in which a beam of light passing through a gaseous medium is capable of generating sound in the medium if the beam is periodically interrupted at some characteristic acoustic frequency.

Conduction of sounds through the bones.

1. Aiding or concerning hearing.
2. A reference to an instrument used to assist hearing; such as, an ear-trumpet.

Referring to the very faint sounds produced by the ear; thought to represent mechanical vibrations in the cochlea.

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.

To detect otoacoustic emissions, researchers insert a miniature probe ­which looks somewhat like a hearing aid and contains a sound source and a sensitive microphone ­into the outer ear canal.

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 noise, various drugs, and bacterial and viral infections.

An abnormal sensitivity to sound, sometimes found in hysteria, in which hearing is abnormally acute.

Any kind of abnormal hearing.

1. Impaired hearing.
2. Auditory illusions or hallucinations.