Audioscan Verifit 2 - Manual (Page 147)

Verifit ® User's Guide Version 4.2 © June 2015
23 Glossary
ABR, Auditory Brainstem Response, The auditory brainstem response (ABR) test gives information about the
inner ear(cochlea) and brain pathways for hearing. This test is also sometimes referred to as auditory evoked
potential (AEP). The test can be used with children or others who have a difficult time with conventional
behavioral methods of hearing screening. The ABR is also indicated for a person with signs, symptoms, or
complaints suggesting a type of hearing loss in the brain or a brain pathway.
AGC, Automatic Gain Control, the means by which gain is automatically controlled by the level of the signal
being amplified. (ANSI S3.22)
AGC-I, input-controlled AGC (see "input compression").
AGC-O, output controlled AGC (see "output compression").
ANSI, American National Standards Institute.
Binaural, literally means "having or relating to two ears." Binaural hearing, along with frequency cues, lets
humans and other animals determine direction of origin of sounds. Similar to diotic which is used in
psychophysics to describe an auditory stimulus presented to both ears.
BSPL, Band Sound Pressure Level, the SPL within a restricted frequency band.
BTE, Behind-The-Ear (hearing aid).
Compression, a type of AGC in which an incremental change in the input level produces a smaller incremental
change in the output level.
CR, Compression Ratio, the ratio of incremental change in input SPL to the resulting incremental change in
output SPL. Used to characterize steady state AGC action; can be a function of input level, duration and
frequency.
CROS, Contralateral Routing Of Signals; a type of hearing aid in which the microphone is at the ear opposite
to the one receiving the amplified sound.
CORFIG, coupler response for flat insertion gain; the transformation added to real-ear insertion gain to
obtain 2-cc coupler gain. Assumes linear amplification.
Coupler, a device used to acoustically couple an earphone or hearing aid to a measurement microphone and to
provide an acoustic load.
DSL, Desired Sensation Level Method, a systematic eardrum (SPLogram) approach to the hearing aid fitting
process that seeks to ensure amplified speech will be audible and comfortable while loud sounds will not be
uncomfortable.
Directional hearing aid, a hearing aid for which the gain is dependent on the direction of sound incidence when
measured under free-field conditions (ANSI S3.22).
EMC, Electromagnetic Compatibility, the unintentional generation, propagation and reception of
electromagnetic energy with reference to the unwanted effects (electromagnetic interference) that such energy
may induce. EMC aims to ensure that equipment items or systems will not interfere with or prevent each other's
correct operation through spurious emission and absorption of electromagnetic interference.
Equalization, process of controlling the SPL (or band SPL) of the stimulus, as a function of frequency, at the
field reference point (ANSI S3.46).
FM, frequency modulation, a method of transmitting information in which the frequency of a radio wave
(carrier) is varied (modulated) by the information (signal). Also, a method of reducing standing waves in a
sound field in which the frequency of a test tone (carrier) is varied by a low frequency triangle or sine wave.
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