Glossary Of Hearing Aid Terms
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A Glossary of Hearing Aid Terms and Definitions Casting the Light of Knowledge into the Ear

How our ears work and the possible need for a hearing aid is an important subject, if perhaps one which should be approached with caution if you're suggesting the use of one for someone else! It can be a bit fretful for children of course and quite daunting for some adults as well. So to offer help, for you or your friends or family, here is a guide to many of the more usually encountered words and terms on this topic:

  • Acquired Hearing Loss
    This is a problem with hearing that begins any time during a person's lifetime after birth. As oppose to congenital hearing loss which is triggered during pregnancy or the birth. (See also Conductive, Congenital, Mixed and Sensorineural Hearing Loss).
  • AOM (Acute Otitis Media)
    Severe form of a fairly common illness of the ear, which results in a highly inflamed eardrum. (See also COM, Eardrum and OM).
  • ALDs (Assistive Listening Devices)
    These are a family of devices designed to help with hearing. Hearing aids are acoustic ALDs. The other types are; Corded, FM, Induction Loop, and Infrared. (See below).
  • ALDs ---- Corded
    These are cheaper systems designed for conversations between two people, the user and a doctor or lawyer or close family member for example, or the TV. They are not recommended for helping the hard of hearing during any group communication.
  • ALDs ---- FM
    FM stands for frequency modulation and this ALD is a system that uses radio waves to send the sound of a speaker's voice to small receivers clipped onto the users' clothes that usually come with a selection of earpieces. Often used in various types of public meetings where the speaker moves about.
  • ALDs ---- Induction Loop
    Often used to help the hard of hearing in places such as churches, classrooms and conference centers; it is a system that uses an electromagnetic field generated from a wire looped around the borders of the given room or space. Signals are sent from the speaker to here and then transmitted throughout the loop where receivers with earpieces or hearing aids equipped with telecoils give benefit to the listener.
  • ALDs ---- Infrared
    These assistive listening devices use infrared light, which is invisible to humans, as a carrier for sonic signals which are transported to same channel receivers with earpieces from a single transmitter. Very often found in courtrooms and at the movies, they can also be purchased affordably for home use when listening to a stereo system or the television set.
  • Amplifier
    One of the components of a hearing aid. Within these circuits, sound is processed, adapted, and amplified according to the required settings that are individual to the user.
  • Amplitude
    This is the height of a sound wave, the higher the wave, the louder the sound.
  • Ampulla
    Sensory cell containing area at the base of the semicircular canals. (See Semicircular Canals).
  • Analog (Of Hearing Aids)
    Analog aids convert sound waves from the outside world into electrical impulses, before processing them, boosting them, and reconverting the electric current into louder sound for the user to hear. Modern electric hearing aids are either analog or digital. (See DSP).
  • Anvil (Can also be known as Incus)
    This is the second of three minute bones in the middle ear collectively called the Ossicles. (See also Middle Ear and Ossicles).
  • Audiogram
    This is the graphical and written documentation of a hearing test. (See Hearing Test).
  • Audiologist
    A qualified professional with a minimum of a master's level degree. An audiologist receives training for testing hearing strengths and weaknesses, and the prescription, fitting and adjusting of hearing aids and other devices.
  • Audiology
    The division of healthcare concerned with analyzing, treating and preventing conditions associated with the lessening or loss of hearing.
  • Audiometer
    An electronic device that measures capabilities of hearing.
  • Audiometry
    A set out and followed procedure to gauge hearing strength. Usually known as a hearing test.
  • Auditory Nerve
    The nerve that sends gathered information from the ear into the brain for interpretation.
  • Auricle
    The earlobe and the rest of the ear that can be seen on the outside of the head are known as the auricle or the pinna.
  • BAHA (Bone Anchored Hearing Aids)
    A type of bone conductor where the unit is attached to the bone behind the ear with a titanium screw. This is preferred by some who may get pressure sores or headaches from a headband used with other bone conductors. (See Bone Conductor Hearing Aids).
  • Binaural Hearing Aid
    One where both ears have their own separate aid attached.
  • Body Hearing Aid
    A body hearing aid offers the most powerful type of hearing aid for those suffering most from hearing loss. Too big to be worn at the ear, it is attached to the body and connected via an earpiece.
  • Bony Labyrinth
    The space in the skull where the inner ear resides.
  • Bone Conductor Hearing Aids
    These can be used by people who because of deformity or severe infection cannot attach a regular hearing aid or earpiece to their ear. The bone conductor is routinely fitted to a headband where a device touches the skin behind the ear and sends sound waves directly through the head bone here to the cochlea, but bypasses the outer and middle ear. (See also BAHA and Cochlea).
  • BTE (Behind-The-Ear) Hearing Aids
    These aids sit behind the ear in a small sturdy case, and send sound through a clear tube to a plastic ear mold which is designed to fit each individual ear. BTEs are the ones best recommended for children as the size and growth of the ears are not problematical for these hearing aids. BTE aids are suitable for all degrees of hearing loss.
  • Cerumen
    The scientific name for the substance usually referred to as ear wax. It is secreted by glands inside the ear as a protection measure, but too much of this can cause difficulties for hearing and can damage some hearing aids.
  • CIC (Completely-In-Canal) Hearing Aids
    The very smallest of all hearing aids. CIC aids are positioned deep inside the ear canal. They are often only used by adults as the ear canals of most children are not big enough for them to fit. These are usually suitable for mild to moderate hearing problems. They cannot be used if ear discharge is a problem.
  • Circuit
    The processing place in a hearing aid where sound is converted to either data (for digital) or electric impulses (for analog) and boosted.
  • COM (Chronic Otitis Media)
    When the illness of the ear Otitis Media is present for more than two months, physicians refer to it as being chronic. (See also AOM, Eardrum, and OM).
  • Cochlea
    This hearing organ makes up the inner ear. Looking like the round shell of a snail, it is composed of a network of liquid filled tubing that also houses the tiniest of hairs. When sound is sent here by the ossicles it causes ripples in the liquid and the hairs to bend. This movement triggers electrical impulses which are transmitted to the auditory nerve. (See Auditory Nerve and Ossicles).
  • Cochlear Implant
    A controversial technique used to help people with hearing impairments by replacing a non-working cochlea. (See Cochlea).
  • Conductive Hearing Loss
    This type of loss of hearing is caused by trouble in the outer or middle ear (where sound is conducted, or directed, through to the inner ear or cochlea). It may either last briefly or permanently depending on the cause which can be varied. Too much ear wax, an inflamed, perforated or punctured eardrum, fluid trapped in the middle ear or damage to the ossicles. These problems can usually be dealt with by medical procedure. (See also Acquired, Congenital, Mixed and Sensorineural Hearing Loss).
  • Congenital Hearing Loss
    This hearing loss is one that exists right away from birth. The causes are not all known, but some have been identified as; a severe illness or disease during pregnancy, very difficult birth conditions, or genetics. (See also Acquired, Conductive, Mixed and Sensorineural Hearing Loss).
  • Cortex
    The part of the brain where information from the senses is processed.
  • Cued Speech
    This involves shaping the hands according to a fixed code which is used to provide extra information to those who are lip-reading.
  • Custom Made
    Anything designed purely to fit the individual ear involved. Ear dimensions can vary quite considerably.
  • db SPL (Decibel Sound Pressure Level)
    These are technical measures of sound used to signify hearing strengths or weaknesses.
  • Decibel (db)
    A decibel is a unit of the loudness of sound.
  • DSP (Digital Sound Processing)
    In hearing aids which are digital rather than analog the incoming sound is changed into streams of data which is comprised of billions of numbers. This leads to more precise processing and boosting of the required frequencies within the overall sound received. (See Analog).
  • Directional Hearing
    This is where the direction of the sound source is correctly identified.
  • Ear Canal
    The pathway in the outer ear which leads to the eardrum.
  • Eardrum (Tympanic Membrane)
    The eardrum lies in the middle ear. When sound waves traveling through the ear canal strike this membrane, it vibrates. These vibrations are then transmitted to the ossicles. The eardrum is highly sensitive and can be perforated or ruptured, or inflamed when subject to the infection known as Otitis Media. (See also AOM, COM, OM and Ossicles).
  • Ear mold
    This is a plastic earpiece used with BTE hearing aids.
  • Earwax
    See Cerumen.
  • ENT (Ear, Nose, and Throat) Physicians
    Doctors who specialize in these three interrelated medical fields. The correct term is Otolarynology.
  • Eustachian Tube
    A tube inside the body that links the cavity of the middle ear to the nose and the throat. It is vital for maintaining the correct air pressure so that the eardrum and ossicles can vibrate properly.
  • Faceplate
    The side of an ear mold which faces outwards.
  • Feedback
    The loud discomforting whistling or squealing that sometime emanates from hearing aids is called feedback. It is caused when boosted sound that has left the aid re-enters it, and is boosted again.
  • Fitting Software
    The computer software used by the audiologist to match programmable hearing aids up to the needs of the individual user. (See Audiologist).
  • FM
    See ALDs ---- FM.
  • Frequency
    The rate of vibration of a sound wave in a period of time. (See also Hertz).
  • Frequency Control (Tone Control)
    These are potentiometers or other controllers on a hearing aid used for fine tuning.
  • Frequency Response
    Which sound waves frequencies are amplified by the hearing aid is its frequency response. Literally meaning which frequencies the device responds to. It will depend both on user need and the environment they are in.
  • Frequency Response Curve
    A graphical representation of a hearing aid's abilities to amplify different frequencies across its operating range.
  • Gain
    The effectiveness of a hearing aid (how much sound is amplified) is known as its gain.
  • Hard Of Hearing
    A term used to describe those people who need the use of hearing aids.
  • Hammer (Can also be known as Malleus)
    The first of the three tiny bones jointly known as the ossicles. (See also Middle Ear and Ossicles).
  • Hearing Aids
    Any devices which assist in hearing.
  • Hearing Loss Level
    This is the degree of hearing difficulties suffered by a hard of hearing person; it is the difference between what they can hear as a minimum and an agreed average for a healthy young person. Hearing loss is usually measured in decibels (db) and is as follows:
    - Average from 25db to 40db ---- Mild hearing loss.
    - Average from 40db to 55db ---- Moderate hearing loss.
    - Average from 55db to 70db ---- Moderate/Severe hearing loss.
    - Average from 70db to 90db ---- Severe hearing loss.
    - Average greater than 90db ----- Profound hearing loss.
  • Hearing Test
    The test carried out by an audiologist to determine the hearing threshold on a person for a number of individual frequencies.
  • Hearing Threshold
    These are the faintest or weakest sounds that can be reliably heard for each given frequency in a hearing test.
  • Hertz (Hz)
    The unit used for measuring frequencies. The cycles of these per second is often expressed in Hz. (See Frequencies).
  • Inner Ear
    The cochlea. (See Cochlea).
  • Incus
    See Anvil.
  • In-Situ
    This is where a hearing test is carried out with the hearing aid already in place. In this case high, medium and low tones are grouped together and created by the hearing aid itself.
  • ITC (In-The-Canal) and ITE (In-The-Ear) Hearing Aids
    Small hearing aids that fit snugly inside the ear and the ear canal. Not recommended for younger children, whose growing ears are too small, older children would have to have them replaced regularly; these aids are for mild to moderate hearing loss, and occasionally for severe hearing loss. They can be damaged by too much earwax or discharges.
  • Lip Reading
    The ability to understand a speaker by watching the movement of the mouth and facial expressions. Speech reading is another term used for this which also contains interpretations of hand gestures and body language.
  • Loudspeaker
    See Receiver.
  • Malleus
    See Hammer.
  • Medical Clearance
    This is the obtaining of a doctor or physician's approval for the purchase of a hearing aid.
  • Microphone
    That component of a hearing aid which collects sound from the outside world as acoustic energy and sends it on to be processed.
  • Middle Ear
    The cavity containing the eardrum and the ossicles where sound arrives from the outer ear and is conducted onwards as vibrations into the inner ear.
  • Mild Hearing Loss
    See Hearing Loss Level.
  • Mixed Hearing Loss
    Hearing problems which are caused by a combination of Conductive and Sensorineural hearing losses. (See Acquired, Conductive, Congenital and Sensorineural Hearing Loss).
  • Moderate Hearing Loss
    See Hearing Loss Level.
  • Noise
    Unwanted sound that obstructs the hearing of the sounds we want to hear.
  • Noise Control Systems
    Manufacturers use these to try to prevent the user from having their signal interfered with by too much noise, background or otherwise.
  • Non-Programmable Hearing Aids
    These simpler versions do not have complicated circuits inside them, and the user must adjust them by using trimmers on the aid to affect such things as bass (low frequency sound), treble (high frequency sound) and maximum volume. (See also Programmable Hearing Aid).
  • Occlusion Effect
    Occlusion is the strange sensation when using an ear mold or hearing aid, that makes the ear feel as if it is blocked up. Users get used to this after a short time period.
  • OM (Otitis Media)
    An infection of the middle ear which causes various amounts of inflammation to the eardrum. It is usually started off by colds, the flu, other breathing problems or a sore throat spreading to the ear. This is an illness which primarily affects children, in the United States around three quarters of those under three will have suffered from this condition at least once. (See also AOM, COM and Eardrum).
  • Organ Of Corti
    A part of the cochlea which contains the tiny hairs that convert sound to nerve impulses. (See Cochlea).
  • Ossicles
    These three bones (the smallest in the human body) act as a team for receiving vibrations from the eardrum and using these to cause the ripples in the liquid of the cochlea. They are known commonly as the hammer, the anvil and the stirrup. Or medically as the malleus, incus and stapes. (See also Cochlea, Eardrum and Otosclerosis).
  • Otology
    The study of the ear, and the prevention and curing of ear diseases.
  • Otosclerosis
    A condition where the ossicles (see above) become immobile because of deformed growth.
  • Ototoxins
    Drugs that can be harmful to the ear and hearing in general because of known and unknown side effects.
  • Outer Ear
    The auricle and the ear canal. Here, sound is collected and directed inwards. (See Auricle and Ear Canal).
  • Oval Window
    This is where the middle ear cavity joins with the inner ear.
  • Pinna
    See Auricle.
  • Presbyacusis
    The problems of poor hearing that habitually come with older age.
  • Profound Hearing Loss
    See Hearing Loss Levels.
  • Programmable Hearing Aid
    An analog or digital hearing aid that is programmable is one that has operating modes set for individual users particular hearing complaints. (See also Non-Programmable Hearing Aids).
  • Rationale
    This is a mathematical formula used by audiologists to help them calculate the amplification needed for every hearing aid they fit according to the results of hearing tests and type of hearing loss involved. The rationales are collated from thousands of statistics on the performance of past hearing aids. (See Audiologist).
  • RECD (Real Ear to Coupler Distance)
    These are factors taken into consideration when correcting the fitting or measuring performance of a hearing aid. They are based on the size differences of ear canals and usually apply when comparing children with adults.
  • Receiver
    That part of the hearing aid which sends the amplified sound into the ear.
  • Residual Hearing
    That part of a partially deaf person's hearing that still operates is known as residual hearing.
  • Saturation Response
    This is the loudest sound that the hearing aid is permitted to create.
  • Sensorineural Hearing Loss
    A permanent form of hearing loss where the hair cells inside the cochlea or the auditory nerve are damaged. This situation can be caused by excessive noise, aging, illness, the side effects of drugs or medicines, injury to the head or an inherited condition. To avoid sensorineural hearing loss, always use proper hearing protection. (See also Auditory Nerve, Cochlea, and Acquired, Congenital, Conductive, Mixed Hearing Loss).
  • Semicircular Canals
    These control our balance. They are connected to the cochlea. (See Cochlea).
  • Sign Language
    A system of hand movements and positioning which is used to represent words and thought concepts by deaf and partially deaf people when trained in its use. Many others who have no hearing problems of their own also learn sign language to help those who are hard of hearing.
  • Severe Hearing Loss
    See Hearing Loss Levels.
  • Speech Reading
    See Lip Reading.
  • Sound Level
    This is the effect on air molecules by acoustic energy (sound waves). Sound levels are measured in decibels, of which there are numerous forms. It is also affected by factors such as air pressure.
  • Stapes
    See below.
  • Stirrup (can also be known as Stapes)
    This is the third of the miniscule team of bones known as the ossicles. (See Ossicles).
  • Telecoil
    A device which fits onto the outside of a hearing aid to ease the use of a telephone for the owner of the aid.
  • Threshold Of Hearing
    See Hearing Threshold.
  • Tinnitus
    A health complaint where a more or less constant ringing or humming is heard in the ear.
  • Vent
    An opening in the ear mold which has a number of functions:
    - To allow air through into the ear which evaporates moisture build up.
    - To permit some sounds through for the natural hearing of people with less serious hearing difficulties.
    - To enable the user to better recognize the sound of his/her own voice.
  • Wax
    See Cerumen.

So there we are. Some of the most often come across terms and definitions for hearing aids and the ear that they can assist.

Knowing what these words mean almost always makes them less scary, especially for children. And although almost all health practitioners in this and other fields understand well the nervousness and fears of those that come to them for help, it is good to familiarize yourself with them first. It's therefore less to take in at a later date where you may find yourself rushed, and also will enable the potential users to ask more pertinent questions.

And if you think you might need one, find out for sure. Our hearing is very important, even doing everyday things like sitting in front of the television can be a lot less enjoyable if you can't hear properly. So don't get left out, get a hearing aid.

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About The Author

Matt Jacks is a successful freelance writer providing valuable tips and advice for consumers purchasing discount digital hearing aids, replacing hearing aid batteries and

This "Glossary of Hearing Aids Terms and Definitions" reprinted with permission.

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