Intro to Audiology Terms

acoustic admittance

the total flow of energy through the middle-ear system expressed in mohms

the reciprocal of impedance, which is expressed in ohms

acoustic feedback

the whistling sound that is created when the signal leaving the receiver of a hearing aid leaks back into the microphone and is reamplified

acoustic gain

the difference, in decibels, between the intensity of the input signal and the intensity of the output signal in a hearing aid

acoustic impedance

the total opposition to the flow of acoustic energy (as in the plane of the tympanic membrane)

it consists of mass reactance, stiffness reactance, and frictional resistance and is influenced by frequency

acoustic neuritis

inflammatory or degenerative lesions of the auditory nerve

acoustic neuroma

a tumor involving the nerve sheath of the auditory nervea

coustic reflex

contraction of one or both of the middle-ear muscles in response to an intense sound

acoustic reflex arc

the path of an acoustic stimulus that ascends from the outer ear to the brain stem and then descends via the facial nerves on both sides of the head to innervate the stapedius muscles in both middle ears

acoustic reflex decay

a decrease in the magnitude of the middle-ear reflex that occurs with constant acoustic stimulation

acoustic reflex threshold (ART)

the lowest intensity at whcih a stimulus can produce the acoustic reflex

acoustic trauma notch

a precipitous increase in hearing loss in the 3000 to 6000 Hz range, with recovery of hearing function at higher frequencies

it is usually, but not exclusively, associated with patients with noise-induced hearing loss

action potential

change in voltage measured on the surface of a neuron when it fires

acute

characterized by rapid onset, frequently of short duration

aditus ad antrum

a space in the middle ear containing the haed of the malleus and the greater par tof the incus

it communicates upward and backward with the mastoid antruma

afferent

carrying impulses from the periphery toward the brain

air bone gap (ABG)

the amount by which the air-conduction threshold of a patient exceeds the bone-conduction threshold at any frequency in the same ear

air conduction

the course of sounds that are conducted to the inner ear by way of the outer ear and middle ear

alternate binaural loudness balance test (ABLB)

procedure that tests for recruitment in unilateral hearing losses

the growth of loudness of pure tones in the impaired ear is compared with that of the opposite ear as a function of increasing intensity

American National Standards Institute

an organization established to oversee the creation and use of guildelines that affect all centers of US business

these include acoustical devices like audiometers, construction equipment, and much more

it is also involved in accreditation of a variety of programs

Americans with Disabilities Act

a public law passed in 1990 to provide equal opportunity for individuals with disabilites

amplitude

the extent of the vibratory motion of a mass from its position of rest to that point farthest from the position of rest

amplitude distortion

the presence of frequencies in the output of an electroacoustic system that were not present at the input, resulting in a disproportional difference between the input and output waves

ampulla

the widened end of each of the three semicircular canals where they return to the utricle

each ampulla contains an end organ for the sense of equilibrium

analog hearing aid

an amplification system in which the electrical signal is analogous to the input acoustical signal in frequency, intensity, and temporal patterns

anechoic chamber

a specially built room with large wedges of sound-absorbing material on all walls, the floor, and the ceiling, whose purpose is to provide maximum sound absorption and to keep reverberation to an absolute minimum

annulus

the ring of tissue around the periphery of the tympanic membrane that holds it in position at the end of the external auditory canal

cochlear duct

scala media basically

cochlear implant

coil and series of electrodes surgically placed in the mastoid and inner ear

itis designed to provide sound to a patient with a profound eharing loss through a processor and external coilco

cochlear microphonic

the measurable electrical response of the hair cells of the cochlea

cold runningn speech

rapidly delivered speech, either prerecorded or by monitored live voice, in which the output is monotonous and the peaks of the words strike zero on the VU meter

commissures

nerve fibers connecting similar structures on both sides of the braincomp

complex wave

sound wave made up of a number of different sinusoids, each with a different frequency

compliance

the opposite/inverse of stiffness

component

pure-tone constituent of a complex wave

compression

that portion of a sound wave where the molecules of the medium are compressed together; also known as condensation

in a hearing aid, a method of limiting the amplification of louder sounds relative to weaker sounds