Glossary of Hearing Loss and Other Terms
Related to Ears
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F G H
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711 Relay Access: 711 is the 3-digit code to dial to reach a
Telecommunications Relay Service (TRS) Operator for use when
using a teletype (TTY) and phoning a person who is deaf or
has limited hearing.
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ABI: (See Auditory brainstem implant.)
ABR: (See Auditory brainstem response testing.)
AC: (See Air conduction.)
Acoustic neuroma: A slow-growing, benign tumor on the auditory
and vestibular nerves that develops when cells that cover and insulate the
Acoustic reflex: A
contraction of muscles in the middle ear in response to loud sounds that
that produces a stiffening of the eardrum. This
helps reduce the damaging effects of loud sounds.
Acoustic room treatment: Using sound-absorbing materials (such
as carpets and acoustical tile) to reduce noise. This makes it easier for hard
of hearing people to understand what is being spoken.
Acoustics: Having to do with sound, the sense of hearing or the
science of sound.
Acquired deafness: A hearing loss that was not present at birth.
Acute otitis media: An infection of the middle ear that often
includes pain, fever and conductive hearing loss.
ADA: (See Americans with Disabilities Act.)
Adventitious hearing loss: A hearing loss that occurs sometime
Adventitious deafness: (Same as Adventitious hearing loss.)
Acquired hearing loss: (Same as Adventitious hearing loss.)
Adverse side effect: A harmful result of a drug as opposed to
the desired therapeutic effect. Often just referred to as a "side effect." For
example, tinnitus and dizziness are common side effects of many
AGC: (See Automatic gain control.)
AIED: (See Autoimmune Inner Ear Disease.)
Air-bone gap: Any difference between how a person should hear
and how they actually hear if some of the sound is being lost as it passes
through the middle ear. In hearing testing, any difference between hearing
responses for earphone or loudspeaker (air conduction) and bone vibrator (bone
conduction). A gap or difference between air-conduction and bone-conduction
responses indicates a conductive hearing loss due to problems in the middle ear.
Transmission of sound to the inner ear by way of the ear canal and the middle
ear. In hearing testing, air-conduction testing is performed by sending sounds
to the ear though an earphone or loudspeaker.
Air conduction pathway: The transmission of sound through the
outer and middle ear to the cochlea.
Air conduction threshold: The hearing threshold for a pure tone
delivered from an earphone or ear inserts.
ALD: (See Assistive Listening Device.)
Alerting device: A visual (usually flashing lights) or tactile
(vibrating) device that alerts a person who cannot hear to sounds such as door
knocks/doorbells, telephones ringing and fire alarms.
ALS: (See Assistive listening system.)
Ambient noise: (Same as Background noise.)
American sign language (ASL): The main visual/gestural (signed)
language of the
Deaf in the United States and Canada. ASL has its own word order and set of grammatical and
Americans with disabilities act (ADA): Public law 101-336 passed
in 1990 that prohibits discrimination on the basis of disability in employment,
transportation, public accommodation, state and local government and
telecommunications. This is a "civil rights act" for persons with disabilities.
Amplification: An increase in the intensity (loudness) of sounds
provided by a hearing aid or assistive listening device.
Amplifier: An electronic device for increasing the strength or
gain of an electrical signal.
Amplified telephone: A telephone that is equipped with a volume
control either built into the handset, the baste of the phone or via an
Amplitude: The physical intensity of a sound. (Subjective
impression of "loudness.")
AN: (See Auditory neuropathy spectrum
AN/AD: (See Auditory neuropathy spectrum
Analog hearing aid: A type of hearing aid that provides
amplification by continuous changes in the voltage of the sound signal being
amplified. All the older hearing aids worked this way. Modern hearing aids are
mostly digital hearing aids.
ANSD: (See Auditory neuropathy spectrum
Anvil: The second of the three bones in the middle ear. Technically
called the Incus.
Apical region: The tip of the snail-shell-shaped cochlea. The
apical region is where low frequency sounds are detected and sent to the brain.
Aplasia: Malformation of the inner ear.
ASL: (See American sign language.)
ASP: (See Automatic signal processing.)
ASR: (See Automatic speech recognition.)
Assertiveness: Behavior that allows people to request their own
rights without interfering with the rights of others. Few hard of hearing people
are assertive. Rather, then tend to be passive.
Assistive listening device (ALD): A broad category of devices
that are designed to help hard of hearing people hear (function) better in specific situations. Many ALDs are used in
conjunction with the person's hearing aids to improve their performance in noisy
situations or when the speaker is at a distance from the hard of hearing person.
Examples of ALDs include amplified telephones,
FM systems, infrared systems and
induction loop systems.
Assistive listening system (ALS): A system used in rooms and
with larger groups to make dialogue accessible. These include
Infrared systems and Induction loop systems.
Ataxia: Impaired coordination that typically reveals itself in a
staggering gait. Gait ataxia is one of the results of a damaged vestibular
(balance) system. It can be result from taking ototoxic drugs.
Atresia: Absence or malformation of the outer or middle ear. For
example, there may be no pinna or ear canal.
Attenuate: To decrease the amplitude (loudness) or energy of a
Audio-coil: (Same as T-coil and
Audiogram: A graphic representation of a person's hearing loss.
More technically, a graph of a person's hearing threshold levels (in
plotted on a chart to show the softest sound a person can detect at various
frequencies (typically between 250 and 8,000 Hz) from low pitch (left side) to high pitch (right side).
Audio induction loop: A type of assistive listening device that
consists of a coil of wire laid around a room and hooked to an
audio devices such as a television or public address system. The coil creates a
magnetic field that transmits sound to people with hearing aids and telecoils
who are sitting inside the loop. They hear clear sound without background noise
Audiological Evaluation: Tests conducted by an audiologist to
determine whether a hearing loss is present, what tones (pitches) are affected,
how severe the hearing loss is and the type of hearing loss. The evaluation also
includes recommendations as to what should be done to ameliorate the hearing
loss. For a more in-depth understanding of
what a complete audiological evaluation entails, read this article.
Audiologist: (awe-dee-ALL-oh-jist) A health-care professional with a Doctor of
Audiology (Au.D.) or a masters degree in audiology and licensed by one of the
audiology associations. Audiologists are trained to identify, measure and
evaluate hearing loss and related disorders—including balance (vestibular)
disorders and tinnitus—and to provide non-medical management of hearing loss,
including hearing aids, assistive devices and rehabilitation.
Audiology: The study or science of hearing. The profession of
audiology is concerned with measurement and rehabilitation of auditory and
Audiometer: A device for presenting precisely measured tones of
specific frequencies (or speech and recorded signals) and intensity (loudness)
levels in order to obtain an audiogram.
Audiometry: The performance of hearing-related tests.
Auditory Brainstem Implant (ABI): An ABI is
similar to a cochlear implant, except the electrodes are implanted directly in
the base of the brain. ABIs are used when a person has NF type 2 and have to
have their auditory nerves cut (which renders them useless as far as cochlear
implants are concerned). People with ABIs generally only hear
environmental sounds--not clear speech. ABI technology is today where CI
technology was 25 years ago.
Auditory brainstem response testing (ABR): A test that can
be used to assess auditory function in infants and young children using
electrodes on the head to record electrical activity from the auditory (hearing)
nerve. More technically, a hearing test that
measures the neurological responses of the auditory nerve and brainstem to a
series of clicking sounds. Basically, it measures
impulses that are sent from the inner ear to the brain when sounds are heard.
The test can be used to screen for hearing loss, estimate hearing
threshold levels, evaluate auditory processing and rule out problems in the
auditory nerve. Also referred to as Brainstem Evoked Response (BSER), Brainstem
Auditory Evoked Potential (BAEP), and Brainstem Auditory Evoked Response (BAER).
Auditory hallucinations: Hearing voices, singing, music or other
phantom sounds. These sounds may be caused by schizophrenia. Also, some drugs
cause auditory hallucinations as a side effect. However, the most common cause
is a damaged auditory system. This often results in Musical Ear Syndrome.
Auditory nerve: (AWE-dih-tore-ee) The eighth cranial nerve that
carries impulses (information) between the cochlea and the auditory cortex in the brain.
Auditory neuropathy spectrum disorder (ANSD): A term used to describe a pattern of
symptoms in which behavioral or ABR measures suggest significant hearing loss
while measures of cochlear function such as otoacoustic emissions appear normal.
More technically, a term that describes a pattern of abnormal findings for a
number of audiometric measures—e. g., auditory brain stem responses (ABR),
pure-tone and speech audiometry, and/or acoustic reflexes, yet normal findings
for otoacoustic emissions (OAE). The most common pattern is the absence of an
ABR with normal OAE. Formerly referred to as Auditory Neuropathy/Auditory
Dyssynchrony (AN/AD) and before 2001 simply as Auditory Neuropathy (AN).
Auditory/oral education: An approach based on the principle that
most hard of hearing children can be taught to listen and speak if they have
early intervention and consistent training to develop their hearing potential.
Also known as Oral deaf education.
Auditory Perseveration: (See Palinacusis.)
Auditory processing disorder: A disorder of auditory processing
resulting from disease, trauma, or abnormal development of the auditory system
in which some of the understanding or clarity (not volume) of sound is lost
within the brain or nerve pathways leading to the brain.
Auditory reflex: Any reflex occurring in response to a sound. If
the ear is essentially deaf, there will not be any auditory reflex.
Auditory rehabilitation: (Same as Aural rehabilitation.)
Auditory therapy: (See Auditory training.)
Auditory trainer: An assistive listening device—basically a
personal FM system—for use in the classroom and/or at home. The benefit is that
the background room noise is not amplified, and the parent or teacher's voice
goes directly to the child's ear from any location, even from another nearby
Auditory training: Listening to environmental sounds, music and
speech to practice recognizing and understanding what has been heard. In other
words, the process of training a person to use their residual
hearing to the best of their ability to recognize, identify and interpret sound.
Aural habilitation: (See Aural
A general term that refers to teaching hard of hearing people how to adjust to, and compensate for, their
hearing losses by making productive use of their residual hearing in
learning spoken communication skills through
speechreading and auditory training. Training in the use of hearing aids is often
included in this process.
Auria: The version of cochlear implant sound processor
immediately preceding the Harmony sound processor from Advanced
Bionics. It is a BTE
Auricle: The external ear (pinna).
Autoimmune inner ear disease (AIED): Hearing
loss or balance problems can arise when the body's immune system gets out of
whack and attacks the inner ear. Normally if you have AIED, you likely also
already have another immune system disease. Click
here for comprehensive article on AIED.
Automatic gain control (AGC): A form of hearing aid circuitry
that automatically adjusts the volume of sound so it remains within a comfortable range for
the person wearing the hearing aid.
Automatic signal processing (ASP): Methods of altering the input
to analog hearing aids to improve hearing.
Automatic speech recognition (ASR): A computer system that
convents the spoken word to text.
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Background noise: Any sound that a person does not wish to hear
or that interferes with what they are trying to hear. Background sounds compete
with speech and often
make it difficult or impossible for a hard of hearing person to understand
BAEP: Brainstem auditory evoked potential. (See
brainstem response testing.)
BAER: Brainstem auditory evoked response. (See Auditory
brainstem response testing.)
BAHA: (See Bone anchored hearing aid.)
Balance system: (See Vestibular system.)
Basal region: The base of the snail-shell-shaped
the middle ear. The basal region detects high frequency sounds and sends them to
Basilar membrane: The central membrane in the cochlea upon which
the hair cells rest. The basilar membrane is contained within the
Behavioral hearing tests: Assessment procedures that involve
observable responses to sound. The same as Behavioral Observation Audiometry.
Behavioral Observation Audiometry (BOA): A hearing test used
with infants and young children in which their behavior (such as eye opening and
heard turning) is observed to see how they respond to sound. This testing can be
unreliable and can be affected by observer bias. It should be used in
conjunction with other tests.
Behind-the-ear hearing aid (BTE): A hearing aid that rests
behind the ear. Sound from the aid is carried through a small clear tube to an
earmold that fits into the ear.
paroxysmal positional vertigo (BPPV): A condition characterized by sudden,
short bursts of vertigo that typically occur with changes in head position. It
is often caused when the otoconia get jolted out of their normal positions.
The fancy medical name is cupulolithiasis.
Bi-CROS: This is a special version of the CROS hearing aid that is
designed for a person with a partial hearing loss in one ear and a total hearing
loss in the other. The person wears what looks like two hearing aids. The one on
the deaf side collects sounds from that side and transmits them to the hearing
aid on the better side, where these sounds are combined with the sounds
amplified from the better side. These combined sounds are then fed into the
better ear. With a BICROS hearing aid, you can hear a person talking to you from
your deaf side.
Bilateral: Referring to both sides.
Bilateral hearing loss: Hearing loss in both ears.
Binaural: Refers to both ears.
Binaural hearing: Hearing with both ears.
Binaural hearing aids: Hearing aids worn in both ears at the
Binaural summation: Sound received from two ears is perceived as louder than sound
received from one ear.
BOA: (See Behavioral observation audiometry.)
Body aid: The largest and most powerful of the conventional
hearing aids. The body of this hearing aid is about the size of a pack of
cigarettes and can be worn on the belt or in a pocket. Sound is carried from the
aid through a small wire that leads to an earpiece.
Bone anchored hearing aid (BAHA): A special
kind of bone conduction hearing aid. A titanium "post" is surgically implanted
into the mastoid bone behind your ear. Once this "post" heals and the bone
firmly grows around it (about a month), the hearing aid itself is snapped to the
post. The hearing aid vibrates the post, which in turn vibrates your skull,
which in turn shakes your cochlea and you hear the sound. BAHA hearing aids work
best for people with conductive hearing losses.
Bone conduction: The transmission of sound (mechanical
vibrations) through the bones of the skull to the inner ear.
This is largely how we hear our own voices.
Bone conduction hearing aid: A hearing aid that works by gently vibrating the
skull to produce hearing, rather than by putting sound in the ear. Bone
conduction hearing aids are used for large conductive hearing losses that cannot
be medically corrected.
Bone conduction testing: A hearing test than involves transmitting
sound to the inner ear via a small vibrator (bone oscillator or transducer) that
is placed on the mastoid bone behind the ear or on the forehead.
Bone conduction threshold: The threshold of hearing sensitivity
to pure tones delivered from a bone-conduction vibrator.
Bony labyrinth: The system of interconnecting pathways of the
inner ear. (See also Vestibular system.)
BPPV: (See Benign paroxysmal positional vertigo.)
Brain fog: Colloquial term used to describe some of the side
effects of damage to the vestibular (balance) system that include memory loss,
groping for words, forgetfulness, problems thinking though things, etc. People
that have severe Meniere's disease or suffer from the effects of ototoxic drugs
that have severely damaged their vestibular system often suffer from "brain
Brainstem auditory evoked potential (BAEP): (See Auditory
brainstem response testing.)
Brainstem auditory evoked response (BAER): (See Auditory
brainstem response testing.)
Brainstem evoked response (BSER): (See Auditory brainstem
BSER: Brainstem evoked response. (See Auditory brainstem
BTE: (See Behind-the-ear hearing aid.)
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CA: (see Communications Assistant.)
Caloric test: A
test that involves circulating water through the ear canal. The doctor or
audiologist observes the resulting eye movements as different water temperatures
stimulate the inner ear.
CAN: (See Computer-assisted note-taking.)
Canal Hearing Aid: A hearing aid that fits entirely within the
CAPD: (See Central auditory processing disorder.)
CapTel: (See Captioned Telephone.)
Captioned Telephone (CapTel): A form of
Telecommunications Relay Service where the person who is deaf
or has limited hearing uses a special CapTel phone and reads the words from the
other party (revoiced by a Communications Assistant), and uses
his/her voice to speak.
CART: (See Communication Access Real-time Translation.)
Originally the acronym stood for Computer Assisted Real-time Translation.
CBT: (See Cognitive Behavior Therapy.)
Central auditory processing disorder (CAPD): A language disorder
that involves the perception and processing of information that has been heard.
Children with CAPD have problems following spoken instructions and usually show
other language-learning problems, even though the inner ear is functioning
Central nervous system (CNS): That part of the nervous system
composed of the brain and spinal cord. Technically, the hair cells in the
cochlea and the auditory nerves are also part of the CNS. Problems in the
auditory parts of the CNS can distort hearing and "mess up" the way your brain
processes what you hear so you may not understand what you hear.
Cerumen: (See Ear wax.)
Ceruminosis: Increased or excessive ear wax build-up. When ear
wax builds up, it can block the ear canal and cause some degree of temporary
conductive hearing loss.
Channel: In regards to cochlear implants, a channel refers to
one of the electrode pairs that are arranged along the electrode array. The
channels are numbered consecutively with channel 1 being the lowest in pitch.
Not all channels have to be used. They can be turned off individually for
various reasons. One reason is that a given channel may affect the facial nerve.
Cholesteatoma: A non-cancerous tumor where skin cells grow uncontrolled
(usually through a hole in the eardrum) and accumulates in the middle ear. It
may also be the result of chronic otitis media. A cholesteatoma damages the middle ear and surrounding structures
and needs to be surgically removed.
Cilia: The tiny "hairs" within the cochlea.
CIC: (See Completely in the canal hearing aid.)
CII Bionic Ear: The internal part of a
particular cochlear implant made by Advanced Bionics, and released in April
2001. The CII Bionic Ear has been superseded by the HiRes 90K
internal component, released in September 2003.
CIS: (See Continuous Interleaved Sampling.)
Clarion (C-1): A previous version of internal part of a
particular cochlear implant made by Advanced Bionics. It was superseded by the
CII Bionic Ear in April 2001.
Clinical hearing loss: A hearing loss that can be detected by
normal audiological testing using the conventional test frequencies between 125
Hz and 8,000 Hz.
Closed captioning: Displaying text of spoken words, often placed at the bottom of movies or
television screens. This allows a hard of hearing viewer to follow the dialogue
(even though he can't hear it) and the action of a program simultaneously. Closed
captioning may be turned on or off at will by the person watching the TV.
CNS: (See Central nervous system.)
Coalition of Organizations for Accessible Technologies
(COAT): A coalition of national, regional, and community-based
organizations which advocates for legislative and regulatory safeguards that
will ensure full access for deaf and hard of hearing people to evolving high
speed broadband, wireless and other Internet protocol (IP) technologies.
COAT: (See Coalition of Organizations for
Cochlea: (COKE-lee-uh) The auditory portion of the inner ear consisting of
fluid-filled channels containing the hair cells. The cochlea is shaped like a
small snail shell and normally consists of two and a half turns. The cochlea
converts incoming sound waves from the middle ear into electrical signals and transmits
these signals to the
Cochlear implant: A device that substitutes for damaged (dead)
hair cells of the inner ear. It consists of an electrode array that
is surgically implanted in the cochlea. It delivers electrical signals to the
auditory nerve from an external processor, enabling people with severe to
profoundly hearing loss to perceive sound again. Cochlear implants are an option
if hearing aids do not give you significant benefit.
Cochlear nerve: Sometimes called the auditory nerve or the
acoustic nerve. One of the two branches of the eighth cranial nerve. It conducts
the hearing signals from the inner ear to the brain. (See also "Eighth cranial
Cochlear system: The hearing system of your inner ear consisting
of the cochlea and the auditory nerve.
Coding strategy: A coding strategy is a series of calculations
used by the cochlear implant system to measure the sound that is presented to
the microphone, analyze its components, and then determine which electrodes
should be stimulated and how they should be stimulated to best represent the
original sound. Next, it generates a code that is set to the implanted portion of
the system. This code tells the implant which channel address to stimulate
within the cochlear implant, when to stimulate it, and how loud that stimulation
should be to accurately represent the sound at the microphone. This happens many
thousands of times per second. Two coding strategies for example are
Cognitive Behavior Therapy (CBT): A counseling
therapy that can be used for people suffering from tinnitus. It includes four
main techniques—cognitive, distraction, relaxation and imagination.
Communication access real-time translation (CART): Captioning speech
in real time so hard of hearing people can read the words a speaker says almost
as soon as they are said.
Communications Assistant (CA): A
Telecommunications Relay Service operator who facilitates telephone calls
between people who are deaf or have limited hearing and other people.
Compendium of Pharmaceuticals and Specialties (CPS): The main
drug reference book used by doctors, pharmacists and hospitals in Canada.
Complete audiological evaluation: A series of hearing tests to
evaluate how well a person hears and understands speech. (See also
evaluation.) For a more in-depth
understanding of what a complete audiological evaluation entails, read this
Completely in the canal hearing aid (CIC): The smallest of all the
hearing aids. It fits completely in the ear canal. As such it is almost
Compression: A form of automatic gain control in a hearing aid
that keep sounds from becoming uncomfortably loud by adding less and less
amplification as sounds get louder and louder.
Computer-assisted note-taking (CAN):
Professional CAN note takers use computers and special software and pre-trained
codes to type as much as they can of what a speaker is saying. Since CAN
operators cannot keep up with normal speakers, not everything is transcribed.
Anyone with good typing skills can summarize what a speaker is saying using a
program such as Word so a hard of hearing person can at least get the gist of
what the speaker is saying.
Concha hearing aid: Another name for an in-the-ear (ITE) or
full-shell hearing aid.
Conditioned audiometry: A type of hearing testing used with
young children. Children are trained (conditioned) to perform some activity
(e.g. dropping a block in a box, pressing a toy button, put a peg in a hole etc.) in response to
sounds. The audiologist uses an audiometer set at varying levels of loudness to
assess the child's hearing loss.
Conditioned orienting response (COR): (Same as
Conditioned play audiometry (CPA): (Same as
Conductive hearing loss: A form of hearing loss arising in the
external ear canal, ear drum or middle ear. It refers to anything that impedes
the passage of sound through the outer and/or middle ear sections by preventing
or not effectively transmitting sound to the inner ear. A conductive loss could
result from something blocking the ear canal, from a ruptured ear drum, or from
anything that restricts the movement of the bones in the middle ear. The most
common cause of conductive hearing loss is fluid (infection) in the middle ear (otitis
Congenital hearing loss: A hearing loss present at birth, or
associated with the birth process, or which develops in the first few days of
may or may not be hereditary.
Continuous interleaved sampling (CIS): A software speech
running cochlear implants. The CIS speech strategy is digital and only fires one electrode at a
time, but various electrodes are fired in rapid succession—833 times per second
for the original software, and 5,156 times per second for the newer Hi-Res
software. This rapid successive stimulation gives the illusion of the continuous
stimulation the SAS speech strategy gives.
Contralateral: On the opposite side,
with reference to a given point. (The opposite of
Contralateral routing of sound hearing aid (CROS): A hearing aid
designed for a person who has normal hearing in one ear and is deaf in the
other. This hearing aid picks up sounds on the non-hearing side and transmits
them to the good ear so the person wearing a CROS aid can hear people speaking
from his deaf side.
Conventional audiogram: An audiogram that covers the frequencies
from 125 Hz to 8,000 Hz.
Conventional hearing aid: A basic hearing aid that uses analog
circuitry. This circuitry processes sound as a voltage rather than as bit as a
digital hearing aid does. These aids tend to be relatively unsophisticated
and usually require the user to adjust the volume as needed.
Cookie-bite hearing loss: Named for the shape of this kind of
hearing loss on an audiogram. Both the high and low frequencies are normal or
near-normal, but there is a broad dip in the mid-frequencies that looks like
someone took a bite out of the top of the audiogram.
Coping strategy: (See Hearing loss coping
COR: (See Conditioned orienting response.)
CPA: (See Conditioned play audiometry.)
C-Print: A computer-aided speech-to-print transcription system.
It is not a word-for-word system like CART, but is more a summary of what was
CPS: (See Compendium of Pharmaceuticals and Specialties.)
CROS hearing aid: (See Contralateral Routing of Sound Hearing
Cued speech: A visual representation of the
phonemes of spoken
language that uses
8 hand-shapes in 4 different locations (cues) on the face in combination with
the natural mouth-movements of speech to distinguish all the sounds of spoken
The medical name for benign paroxysmal positional vertigo
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DAI: (See Direct audio input.)
dB: Abbreviation for decibel—a tenth of a bel. Named
after Alexander Graham Bell, thus the "B" is always capitalized in his honor.
deaf: A person with little or no measurable hearing, i. e. 90+
dB hearing loss. A person with severe or
profound hearing loss.
Deaf: When capitalized, Deaf refers to those who consider
themselves a part of the Deaf culture, and choose to communicate using a signed
language such as American Sign Language (ASL), instead of spoken communication.
Decibel (dB): The unit that measures the intensity (loudness) of
sound. It is used to express the degree of a person's
hearing loss. The smaller the number, the better the hearing. Normal hearing
thresholds range between 0 and 20 dB. More technically, a decibel is a unit of measure that defines sound intensity
based on sound pressure level (db SPL). Decibels also measure how a person’s
hearing compares with a normal hearing level (db HL). A decibel is one-tenth of a Bell. (Named after
Alexander Graham Bell.) It is the loudness units hearing level and hearing loss are
measured in. The decibel is a relative measurement of sound intensity or
pressure, based on a logarithmic relationship between two sources where one
serves as the reference. 0 dB is the baseline norm—not the absence of
sound. People with very sensitive hearing can hearing sounds softer than 0 dB.
Sounds softer than 0 dB are expressed in negative numbers, thus -20 dB.
Desired sensation level (DSL): A hearing aid fitting method
designed specifically for children.
Differential diagnosis: Determining which of two or more diseases with
similar symptoms is the one from which a person is suffering. This is done by
systematically comparing and contrasting various symptoms.
Digital hearing aid: A hearing aid that provides amplification
by processing sounds as bits (numbers) instead of as a voltage. This is the way
computers work. Digital hearing aids can control or modify sound in almost an
infinite number of ways through its programs.
Digitally-programmable analog hearing aid: (See
Digital signal processing (DSP): Improving hearing with
manipulation by mathematical formula of a sound signal that has been converted
from analog to digital.
Diplacusis: (dip-lah-KOO-sis) The abnormal perception of sound
either in time or in pitch, such that one sound is heard as two
separate sounds. Or more simply, hearing a single tone as if it were two
tones of different pitch. This name comes from the two Greek words "diplous"—double, and "akousis"—hearing.
Also known as Paracusis duplicata.
Diplacusis binauralis: (dip-lah-KOO-sis by-nar-RAL-is) is a
condition in which the same sound is heard differently in each ear.
Diplacusis dysharmonica: (dip-lah-KOO-sis dis-har-MON-ih-kah) is
a condition in which the same sound is heard at a different pitch in each
Diplacusis echoica: (dip-lah-KOO-sis eh-KOE-ih-ka) as it's name
where you hear the same sound repeated a fraction of a second later in the affected ear—thus you hear
the original sound followed by an "echo" of the original sound.
Diplacusis monauralis: (dip-lah-KOO-sis moh-nar-RAL-is) is where
you hear a single sound as two different sounds in the same ear.
Direct audio input (DAI): The capability of connecting a sound
source, such as a TV or CD or DVD player directly into a hearing aid. DAI bypasses the hearing
aid's microphone by plugging a cord connected to a sound source directly into
the hearing aid. Most hearing aids do not have the necessary DAI connections
(called boots or shoes) so you have to ask for this specifically if you want it.
Sometimes used to refer to the connection of an FM auditory trainer directly
into a hearing aid.
Directional microphone: A microphone that lets a person focus on
a sound coming from one direction rather than picking up sounds equally from all
Disarticulation: A break or separation in the middle ear bones.
Discrimination: Hearing clarity—the ability to tell apart
(discriminate between) similar-sounding words such as "fun" and "sun." People
with normal hearing generally have 100% discrimination. If your discrimination
scores drop below 40% to 50%, you won't understand much of what you hear, no
matter how loud it is. Speech then sounds more like gibberish or a foreign
language. Discrimination is always expressed as a percentage. Now called
Word Recognition (WR) testing.
Dispensing audiologist: An audiologist who sells and fits
hearing aids, evaluates hearing and provides some aural rehabilitation. Most
audiologists are now dispensing audiologists.
Disposable hearing aid: A hearing aid that is mass-produced to
be so inexpensive that it is thrown away once its battery has worn out—usually
in 30 to 45 days.
Distortion: The inexact reproduction of sound. Hearing aids,
like all electronic devices produce a small amount of distortion.
Dix-Hallpike test: A test to determine whether you have
The test requires moving quickly from a seated position to lying down with your
head at a 45-degree angle.
Dizziness: This is a general term that people describe variously
as feeling faint, giddy, light-headed, unsteady or woozy. Others feel a sense of
imbalance or disequilibrium. Very often dizziness is one of the first signs that
a ototoxic drug is beginning to affect the balance system.
Dominant genetic condition: An inherited condition in which one
parent carries an abnormal dominant gene. More technically, a single gene of the
gene pair that produces a physical characteristic (such as hearing loss) without
reference to the other gene in the gene pair. Dominant characteristics are
passed by only one parent. Thus each child born to a parent with a dominant gene
for hearing loss will have a 50% chance of being hard of hearing himself and
will carry this dominant gene, and a 50% chance of having normal hearing and not
carrying the dominant gene.
Drop attack: A sudden case of acute vertigo
such that the person loses their balance and drops to the ground as though they
had been hit by a sledgehammer. Some people with severe Meniere's disease
experience drop attacks from time to time.
DSL: (See Desired sensation level.)
DSP: (See Digital signal processing.)
Dynamic range: The range of loudness between the softest sound
that a person can hear and the loudest sound they can stand (Uncomfortable
loudness level). Hearing aids should be adjusted to keep all sounds
within this range—although this is not always possible if you have a
severely-collapsed dynamic range. The normal dynamic range is about 120 dB,
while the dynamic range of a person with a severe or profound hearing loss may
only be about 30 dB.
Dysacusis: Any impairment of hearing involving difficulty in
processing the details of sound as opposed to any loss of sensitivity to sound.
Also, a condition in which ordinary sounds produce discomfort or pain in the ear.
Dysyncrony: (See Auditory neuropathy/Dysyncrony.)
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EABR: (See Electrical auditory brainstem response testing.)
Earbud: A small transducer (earphone) that is inserted into the
ear canal. Like earphones, earbuds deliver sound to the ear, but for some, they
are more comfortable that earphones.
Ear canal: The inch-long pathway leading from the outer ear to the eardrum. The ear
canal produces cerumen (ear wax) and contains hairs that prevent bacteria and
foreign objects from reaching the eardrum.
Eardrum: (See Tympanic membrane.)
Eardrum perforation: A hole in the eardrum.
Ear impression: An impression or cast of the ear canal made to
determine the exact size and shape of an ear. The impression is used to
make in-the-ear hearing aids, earmolds for BTE hearing aids or custom-made ear
Ear infection: The presence and growth of bacteria or viruses in
the ear. (See also acute otitis media.)
Early intervention services: Services provided by both public
and private agencies to infants and toddlers and their families. These services
are designed by law to support families in enhancing a child's potential growth
and development from birth to age three.
Earmold: The part of a behind-the-ear hearing
aid that fits into the ear and directs sound from a BTE hearing aid into the
ear canal. It also helps hold the hearing aid in place. It is typically made of
plastic or vinyl.
Ear tubes: (See Pressure equalization tube.)
Ear wax: Wax secreted from glands in the ear canal that keeps
the skin of the ear dry and protects it from infection. The medical term is
Educational audiologist: An audiologist with special training
and experience in providing auditory rehabilitation services to children in
Educational interpreter: An interpreter that specializes in
classroom interpreting. (See also Interpreter.)
Eighth cranial nerve: Sometimes called the vestibulocochlear
nerve. It divides into two parts—the cochlear (auditory) nerve responsible for
hearing, and the vestibular nerve responsible for balance. This nerve carries
hearing and balance information from the inner ear to the brain. If it is
damaged or diseased, you could experience things such as hearing loss,
hyperacusis, dizziness, loss of balance,
vertigo, nausea and vomiting.
Electrical auditory brainstem response testing (EABR): This is a
method of obtaining an ABR but using the sound generated by a
This test assists in determining how well the auditory system of a young child
is responding to the stimulation generated by the implant. (See also
brainstem response testing.)
Electrical stapedius reflex test (ESRT): An objective measure
that can be useful in establishing a most comfortable level in children with
cochlear implants who are unable to provide feedback to the
the loudness of sound. A small probe is placed in the opposite ear. The
stimulation level of the implant is increased until a small muscle reflex is
seen in the opposite ear. This muscle reflex is present in most people and
occurs at a level that is loud, but still comfortable.
Electrode array: In cochlear implants, the implanted part has a long,
flexible portion that is inserted into the cochlea though a small opening. This
portion of the implant is called the electrode array.
Electronystagmography (ENG): A battery of tests that evaluate
the interaction between the balance parts of your inner ear and your eye
Endolymphatic hydrops: The accumulation of excessive amounts of
endolymph (an inner-ear fluid) caused either by over-production or
under-resorption. This is a synonym for or variation of Meniere's disease.
ENG: (See Electronystagmography.)
ENT: Ear, Nose and Throat doctor. (See
ERA: (See Evoked response audiometry.)
ESRT: (See Electrical stapedius reflex test.)
Etiology: The cause of a problem, disease, pathology, etc.
Eustachian tube: (yoo-STAY-shun) The small tube connecting the back of the
throat to the middle ear that allows air into the middle ear and allows
naturally-occurring fluid to drain from the middle ear. During yawning and swallowing it temporarily opens to
supply air to the middle ear and to equalize the pressure in the middle ear to
that of the outside atmospheric air pressure.
EVAS: Enlarged Vestibular Aqueduct Syndrome. (See
vestibular aqueduct syndrome.)
Evoked response audiometry (ERA): A hearing test which uses an
EEG (electroencephalograph) and computer analysis to directly record the brain's
response to sound. Useful in helping to determine a child's hearing level when
the child is too young to cooperate with the audiologist. (See also
brainstem response testing.)
External auditory canal: The
ear canal—that portion of the
external ear between the pinna and the eardrum.
External ear: The outer portion of the ear that is normally
visible. Components of the external or outer ear include the pinna and the
external ear canal.
External ear canal: (See External auditory canal.)
Expressive language: Speaking (talking). This usually includes
vocabulary and sentences.
Eyeglass hearing aid: A style of hearing aid, popular in the
1950s through the 1970s, in which the hearing aid was built into the eyeglass
frame. They were similar in many ways to BTE hearing aids and used similar
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FDA: (See Food and Drug Administration.)
Feedback: A high-pitched whistle or squeal that’s made when an
amplified sound is picked up by a microphone and re-amplified. For example, it occurs when the sound coming out of
a hearing aid leaks out of the ear canal, gets back into the hearing aid's microphone
and is amplified over and over until all it does is howl at its maximum
loudness. Feedback can be caused by as earmold or hearing aid that does not fit
properly, from a cracked or damaged earmold (or tube in BTE hearing aids) or from a damaged hearing aid.
Many modern digital hearing aids have special anti-feedback circuitry to prevent
(or greatly reduce) feedback.
Feeling of fullness in ears: May be caused by a physical
condition—e.g. fluid in the middle ear, or by Meniere's disease, or it may be a
psychological feeling—the result of rapidly losing some of your hearing.
When this happens, your brain thinks that your ear must be "stuffed" or
"blocked" or else you'd hear normally, wouldn't you—hence the feeling of
Fidelity 120: The name of the sound processing strategy (software)
for the Harmony and Platinum cochlear implant sound processors. It works with
the HiRes 90K and CII implants from Advanced Bionics.
Filter: Acoustically, a device that allows the passage of
certain frequencies and attenuates others.
Fingerspelling: Using hand-shapes to represent the letters of
the alphabet in order to spell out words.
FM system: (See Frequency modulation system.)
Food and Drug Administration (FDA): This is the government
agency responsible for approving and regulating drug use in the USA.
Footplate: The base of the stirrup (stapes) which rests on the
oval window in the middle ear.
Frequency: The unit of measurement related to the pitch of sound. It is the number of cycles or
number of complete vibrations in one second. Frequency is now expressed in
(Hz). (It used to be expressed in cycles per second [CPS].) The more cycles per
second, the higher the pitch. Human ears normally
can hear sounds between 20 and 20,000 Hz.
Frequency modulation system (FM): A wireless assistive listening device
that picks up a speaker's voice through a microphone and transmits it, using
radio waves, to a person wearing a corresponding FM receiver. The device
effectively moves the speaker's mouth right up to the hard of hearing person's
ears thus removing background noise and distance problems.
Frequency response: The range of frequencies to which a hearing
aid can respond, adjusted to your degree of hearing loss.
Full-shell hearing aid: Another name for an ITE aid.
Functional gain: The difference in a person's responses between
aided and unaided threshold measures. Functional gain is less reliable and valid
than other methods of testing aided benefit.
Functional hearing loss: A hearing loss that is not caused by
any organic condition. In other words it is a "psychological" hearing loss,
because the hearing system is working properly.
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Gain: An increase in the amplitude or energy of an electrical
signal with amplification. Gain is the difference in amplitude between the input
signal and the output signal.
Glomus jugulare tumor: A tumor that may grow in the middle ear
and can interfere with the vibration of the middle ear bones (ossicles).
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Habituation: Habituation is the term used when you are no longer
aware of your tinnitus except when you focus your attention on it. When
habituation occurs, your tinnitus is no longer intrusive and annoying. It is
HAC: (See Hearing aid compatible.)
Hair cells: Sensory cells in the inner ear where nerve endings
attach to the auditory or vestibular nerves. Hair cells within the cochlea
convert sound waves into electrical (nerve) impulses that are carried by the brain. Hair
cells in the vestibular labyrinth respond to motion.
Half-shell hearing aid: A style of hearing aid that is a bit
larger than a canal aid, but is smaller than an
Hammer: The first, and largest, of the three middle ear bones. It is the bone
touching the eardrum. Technically called the Malleus.
Hard of hearing: A term used to describe people with hearing loss.
Their losses can range from slight to
profound. Hard of hearing people understand
some speech with or without hearing aids.
Harmony: The latest cochlear implant sound processor model from Advanced
Bionics. It is a BTE
style. It works together with the HiRes 90K implant and with the earlier
CII Bionic Ear implant, and can use high resolution sound
processing strategies such as the Fidelity 120. The Harmony processor includes a built-in
HAT: (See Hearing assistive technology.)
Hawthorne Effect: This is the term used to describe the sense of
relief and improvement some people experience just because someone is doing
something for their condition.
Head shadow effect: This refers to the amount of sound that is
blocked by a person's head before it can reach the opposite ear. This reduction
in sound is an issue for people who only have hearing in one ear, or for people
who choose to wear a hearing aid in only one ear.
Hearing aid: A device that amplifies sound and directs it into
the ear canal. A hearing aid usually consists of a microphone, amplifier and
receiver. Hearing aids come in 4 basic styles: In the ear (ITE),
behind the ear
(BTE), body aid and eyeglass hearing aid. Body aids are seldom used except for
profound losses. Eyeglass hearing aids had their heyday in the 1960s and 1970s.
They are not used today.
Hearing aid compatible: Refers to devices that
won't cause interference to hearing aids such as cell phones. Cell phones that
are compatible with digital hearing aids have a rating of M3/M4 for microphone
use, and a rating of T3/T4 for t-coil use.
Hearing aid dealer: A person who sells and fits hearing aids,
arranges for repairs, and sometimes counsels in their use.
Hearing aid dispenser: Same as hearing aid dealer. It just
sounds more professional.
Hearing aid evaluation: The process of selecting an appropriate
hearing aid. The audiologist will evaluate different types of hearing aids to
determine which is best suited to a particular hearing loss.
Hearing aid trial: A period of time (usually 30 days) during
which a person may try hearing aids that were custom made for them. If
unsatisfied for any reason, the person should be able to return them for a
refund (minus an agreed upon trial fee. Often this fees is 10% of the selling
price.) Not all audiologists charge a trial fee.
Hearing Assessment: (See Complete audiological evaluation.)
Hearing assistive technology (HAT): A relatively new term that
encompasses both assistive listening devices (ALDs) and
alerting devices for
hard of hearing people.
Hearing dog: A service dog that has completed a training course
to alert its hard of hearing owner to a variety of sounds in different
environments including such things doorbells, smoke alarms, wake-up alarms, baby
cries, etc. Sometimes called "hearing ear dogs."
Hearing ear dog: (See Hearing dog.)
Hearing evaluation: (See Complete audiological evaluation.)
Hearing impaired: Describes people with any degree of hearing loss.
This term is disliked by both deaf and hard of hearing people and is no longer
politically correct. The preferred terms are "people with hearing loss," "hard
of hearing" or "Deaf".
Hearing in noise test (HINT): A hearing test (usually used in
testing people with cochlear implants) in which sentences are spoken against a
background of white noise.
Hearing instrument specialist (HIS): A person who sells hearing
aids and is licensed by the state to do so. They are required to pass a test for
licensure to guarantee a minimal level of competence.
Hearing level (HL): The decibel level of sound
as it relates to normal hearing. Since hearing sensitivity plotted using the
Sound Pressure Level (SPL) scale shows perfect (normal) hearing a a wavy line
rather than a flat line (because our ears are not equally sensitive to all
frequencies of sound), it is hard to determine how much hearing loss a person
has. Thus, the Hearing Level scale was developed for testing human hearing with
audiometers. The resulting audiogram for perfect (normal) hearing is a flat line
at 0 dB. since each test frequency is automatically adjusted (either + or -
depending on human sound sensitivity at that frequency) to result in a flat
line. Now, hearing loss readily shows up as any deviation from this flat HL
line. That is why sound meters measure sound levels in SPL and audiometers measure peoples' hearing sensitivity
in HL. (See Sound Pressure Level.)
Hearing loss: the loss of hearing ability characterized by
decreased sensitivity to sound in comparison to normal hearing. Hearing loss may
be conductive, sensorineural, or mixed. Hearing loss
ranges from slight to
profound. Typically the classes of hearing loss are based on the average hearing
loss at 500 Hz, 1000 Hz and 2000 Hz. Here is one commonly used classification.
- Normal hearing: -10 to 15 dB
- Slight loss: 16 to 25 dB
- Mild loss: 26 to 40 dB
- Moderate loss: 41 to 55 dB
- Moderately severe loss: 56 to 70 dB
- Severe loss: 71 to 90 dB
- Profound loss: 91 to 120 dB
Hearing loss coping strategies: Ways to
successfully deal with your hearing loss. There are 5 basic areas you need to
cover in order to successfully cope with your hearing loss. They are:
- Psychologically and emotionally adjust to your hearing loss. This
includes working through the grieving process for your hearing loss.
- Wear properly fitted hearing aids if they will
- Use assistive listening devices (ALDs) to supplement
your hearing aids in difficult listening situations.
- Learn to speechread.
- Practice the myriads of little (and free) coping skills such as getting
close to the speaker, having light on the speaker's face, telling the person
you are talking to what they need to do so you can effectively communicate
with them, cutting out background noise, etc.
Hearing screening: Simple testing of the ability to hear selected
frequencies at sound levels within normal hearing limits. Screenings are used to
identify people with significant hearing loss and to refer them for more
Hearing threshold: The quietest level a person can hear at least
50% of the time under ideal conditions.
Hemianacusia: (hem-ee-an-ah-KOO-see-ah) Hearing loss in one ear.
Hereditary hearing loss: Hearing loss that is passed genetically
though generations of a family. Hearing loss can be passed by
Hertz: The frequency or pitch of a sound in cycles per second. It is abbreviated as
Hz. It was named after the German physicist Heinrich Rudolf Hertz.
HINT: (See Hearing in noise test.)
HiRes 120 (HiRes with Fidelity 120): A sound processing strategy
that runs the new Harmony processor and provides up to 120 spectral bands.
Previous technology only provided between 12 and 22 spectral bands. It uses
current steering technology to increase spectral resolution to as many as 120
spectral bands. This technology only works with the Harmony
and Platinum Sound Processors.
HiRes 90K: The latest internal part of a
particular cochlear implant made by Advanced Bionics. It was released in
September 2003. It works with the Harmony and Platinum sound processors.
HIS: (See Hearing instrument specialist.)
HL: (See Hearing level.)
HOH: Abbreviation used on the internet for "Hard of Hearing".
Homophene: (HOE-moe-feen) Two or more words that sound differently, but look
identical on a person's lips. For example, pat, bat and mat all look identical
on a person's lips so you cannot tell them apart just by lipreading.
Hypacusis: Hearing loss of a conductive
or sensorineural nature. (See Hypoacusis.)
Hyperacusis: Abnormal hearing sensitivity. Some times described
as "noise intolerance." If you have hyperacusis, you now perceive sound of
normal volume as much too loud. In fact, your may perceive them as being
painfully loud. Hyperacusis can be caused by exposure to loud sounds, or as a
result of taking certain drugs. Hyperacusis can be defined as an abnormally
strong reaction to sound occurring within the auditory pathways. At the
behavioral level, it is manifested by a person experiencing physical discomfort
as a result of exposure to sound (quiet, medium or loud). The same sound would
not evoke a similar reaction in an average listener. The strength of the
reaction is controlled by the physical characteristics of the sound, e.g., its
spectrum and intensity.
Hypnagogic: The transitional state
preceding sleep during which (auditory) hallucinations may occur. (See also
Hypnopompic: The occurrence of visions
or dreams (including auditory hallucinations) during the drowsy awakening state
following sleep. (See also Hypnagogic.)
Hypoacusis: (See also Hypacusis.) Reduced
hearing. Hearing loss.
Hz: (See Hertz.)
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IDEA: (See Individuals with Disabilities Education Act.)
Idiopathic: Having an unknown cause. If the doctors don't know
what caused your hearing loss, they say you have idiopathic hearing loss.
IEP: (See Individualized education program.)
Impedance audiometry: Testing to measure the ability of the
middle ear to conduct sound to the inner ear.
Impedance measurements: A physical measurement of a sound
reflected off the eardrum and analyzed to reveal characteristics of the middle
ear. (See also Tympanometry and
Impedance testing: (See Impedance audiometry.)
Incus: The second of the three bones in the middle ear. Commonly
called the Anvil.
Individualized education program (IEP): A team-developed written
document developed with input from the child's parents, the child (when
appropriate), teachers, school administrators and special service providers. The IEP
refers to the formal educational plan that is developed for each child who
receives special services through a local school district. It outlines the goals for education and therapy for a student
with a disability, and provides a guideline for achieving them. An IEP for a
hard of hearing child should take into consideration such factors as:
- The communication needs of the child, and the family's preferred mode of
- Linguistic needs.
- Severity of the hearing loss and the potential for maximizing auditory ability.
- Academic level.
- Social and emotional needs, including opportunities for peer interactions and
Individualized family service plan (IFSP): A team-developed
written plan for providing early intervention and other services to eligible infants and toddlers (aged 0 to 3 years)
and there families which addresses:
- Assessments of the child's strengths and needs, and identification of services
to meet such needs.
- Assessments of family resources and priorities, and the identification of
supports and services necessary to enhance the capacity of the family to meet
the developmental needs of the infant or toddler with a disability.
- A written individualized family service plan developed by three members of a
multidisciplinary team including the parent or guardian.
Individuals with Disabilities Education Act (IDEA): The
individuals with disabilities in education Act PL94-142, revised.
Induction loop: (See Audio induction loop.)
Inflection: A change in the pitch of the speaking voice to add
meaning or emphasis to a word or phrase.
Infrared system: A kind of assistive listening device that
transmits amplified sound by light waves to a receiver, thus eliminating
background noise and distance problems.
Inner ear: The third (innermost) section of the ear where sound
vibrations and balance signals are transformed into nerve impulses. The inner
ear contains the cochlea (organ of hearing) and the
labyrinth or vestibular
system (the organ of balance).
Intensity: The loudness of a sound. Measured in
Interaural Pitch Difference (IPD): More
commonly known as Diplacusis dysharmonica, IPD is where
you hear the same sound at different pitches in each ear.
Internal feedback: A whistling or squealing that results when
sound that is supposed to go into the ear goes instead directly to the
microphone through a damaged hearing aid case and becomes amplified again and
again. Internal feedback can also be due to an electronic fault in a hearing
aid. In contrast, external feedback is the result of the ear mold not fitting
tightly and allowing sound to escape from the ear canal and reach the
Interpreter: A person who conveys the spoken message to a person
with hearing loss by the use of sign language (visible movements of hands, body
and face), orally (silently mouthing the words) or with Cued speech. Sign
language interpreters are by far the most common.
In-the-canal hearing aid (ITC): A type of hearing aid that fits
partly in the ear canal but extends to the bowl of the ear.
In-the-mouth hearing aid (ITM): A type of bone
conduction hearing aid that fits in the mouth and uses tooth (bone) conduction
to transmit the sounds to the inner ear.
Intonation: (The same as Inflection.)
Intratypmanic: Through the ear drum. For example, an
intratypmanic injection of drugs through the eardrum into the middle ear.
IPD: (See Interaural Pitch Difference.)
Ipsilateral: On the same side, with
reference to a given point. (The opposite of
ITC Hearing aid: (See In-the-canal hearing aid.)
ITE Hearing aid: The general abbreviation for any in-the-ear
hearing aid. Also, specifically, a type of hearing aid that fills most of the
bowl of your ear. An ITE aid is also called a full-shell or concha aid.
ITM Hearing aid: (See In-the-mouth hearing aid.)
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Labyrinth: (See Vestibular labyrinth and
Large vestibular aqueduct syndrome (LVAS): A genetic condition
where the vestibular aqueduct is larger than normal. The result is that many
people with enlarged vestibular aqueducts suffer from hearing loss from head
trauma or from rapid changes in pressure. For a more
in-depth understanding of large vestibular aqueduct syndrome, read this article.
LDL: (See Loudness Discomfort Level.)
Left-corner audiogram: Measurable hearing only at the
frequencies of 125, 250 and 500 Hz. Thresholds are usually above 70 dB.
Linear hearing aid: A hearing aid that amplifies sound by a set
amount (e. g. 20%, 50%, etc.) at any particular pitch; regardless of the initial
volume. This can result in soft sounds not being amplified enough to be hearing,
and very loud sounds being amplified so that they are much too loud. Most older
hearing aids had linear amplifiers.
Lipreading: Watching the mouth of a person speaking as a method
to help a hard of hearing person understand what they are saying. (The modern
term is speechreading.)
Listening strategy: Any method or plan that helps a person to
hear in a particular situation, often called a hearing loss coping strategy. The
goal is to identify the situations where a person has the most difficult
hearing, or has the most need to hear, and then modify the situation in some way
to gain a hearing advantage.
Localization: The ability to determine the source or direction
of a sound.
Loop system: (See Audio induction loop.)
Loudness: The subjective impression of "amplitude" or the
intensity of a sound.
Loudness Discomfort Level (LDL): An
audiological test used to determine at what level sounds become uncomfortably
loud. If your scores are lower than normal at any given frequency you likely
suffer from Recruitment or
LVAS: (See Large vestibular aqueduct syndrome.)
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Mainstreaming: The concept that students with disabilities
should be integrated with their non-disabled peers to the maximum extent
possible, when appropriate to the needs of the student with the disability. This
concept means that hard of hearing and Deaf children should go to regular
schools rather than to special schools for the Deaf.
Malleus: The first of the three middle ear bones. It is the bone
touching the eardrum. Commonly called the Hammer.
Map: The program stored in the speech processor of a
implant that tells the system how to process sound on each channel so that it is
most audible and comfortable for the individual user. Each implant user's map
varies considerably from every other user. Maps also change over time.
Mapping: The process of programming a cochlear implant
processor with various speech strategies.
Masking: Any sound that serves to cover up another. In regards
to hearing aids, it usually refers to background sounds covering up what a
person wants to hear, or to the sound coming from the hearing aid helping to
cover up a person's tinnitus.
Masking noise: Sound used by an audiologist to prevent one ear
from hearing while the other is being tested.
Mastoid bone: The bone located behind the ear in which your inner ear is embedded. The "bump"
behind your ear is called the mastoid process.
MCL: (See Most comfortable loudness level.)
Meniere's disease: A syndrome that consists of
tinnitus, a feeling of fullness in the affected ear and a fluctuating
loss. It is thought to be caused by fluid imbalance in the
Meningitis: A bacterial or viral inflammation that can cause
auditory disorders due to infection or inflammation of the inner ear or
MES: (See Musical ear syndrome.)
Middle ear: An air-filled cavity, about the size of a pea,
between the eardrum and inner ear containing three tiny bones (called
(hammer), incus (anvil) and stapes (stirrup)—that conduct sound from the eardrum
to the inner ear via the oval window.
Mild hearing loss: A hearing loss ranging between 26 and 40 dB.
Mini-canal hearing aid: A hearing aid that is between a
canal aid in size.
Minimal auditory deficiency (MAD): A hearing loss generally of
only 10 to 15 dB below normal. Hearing thresholds are between 20 and 35 dB.
Basically equivalent to a slight to mild hearing loss.
Minimum Masking Level (MML): An audiological
test that can be used to measure the effect of sound on tinnitus. The MML is the
softest level of sound that makes you unable to hear your tinnitus.
Misophonia: Having a negative attitude
towards sound or certain sounds that may result in uncontrolled anger.
Misophonia can be defined as abnormally strong reactions of the autonomic and
limbic systems resulting from enhanced connections between the auditory and
limbic systems, but do not involve a significant activation of the auditory
system. The strength of the person’s reaction is only partially determined by
the physical characteristics of the upsetting sound and is dependent as well on
the person’s previous evaluation and recollection of the sound (e.g., sound as a
potential threat, and/or the belief that the sound can be harmful), the person’s
psychological profile and the context in which the sound is presented. (See also
Mixed hearing loss: A combination of both sensorineural (inner
ear) and conductive (middle ear or outer ear) hearing loss. The
an air-bone gap of 10 dB or more.
MM: A colloquial abbreviation for Meniere's disease from the Latin
"Morbus Meniere" meaning "disease of Meniere".
MML: (see Minimum Masking Level.)
Moderate hearing loss: A hearing loss ranging between 41 and 55
Moderately severe hearing loss: A hearing loss ranging between
56 and 70 dB.
Monaural: Referring to just one ear, as opposed to binaural—both
Monaural amplification: Using one hearing aid instead of two.
Most comfortable loudness level (MCL): The volume at which
sounds are most comfortable for a hearing aid user.
Multi-memory hearing aids: Hearing aids that have the ability to
store different listening programs for access by the user. Many
aids have 3 or 4 memories.
Musical ear syndrome (MES): Hearing phantom sounds that may
resemble voices and music but are too vague to understand such as hearing a
radio playing from another room. At other times, MES manifests itself as
perfectly clear, yet phantom, music or singing, often repeated endlessly. For a
more in-depth understanding of Musical Ear Syndrome,
read this article.
Myringotomy: A small incision made in the eardrum by a physician
to equalize air pressure and/or to drain infection or fluid from the middle ear.
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Natural environment: The setting where the child typically
spends most of his time. For example, a child at age 24 months would likely
spend time at home or in a childcare setting. These settings are the child's
Natural language: Language acquired primarily though the
accessible sensory channels.
Neckloop: A loop of wire worn like a necklace that creates a
magnetic field that can transmit sound when plugged into a portable radio or
personal ALD such as an FM or
Nerve damage: Damage to the hair cells (nerve endings) in the
Nerve deafness: The old (and very misleading) term for sensorineural
hearing loss. In actual fact, there is very little true nerve deafness. (See
sensorineural hearing loss.)
Neurologist: A medical doctor whose specialty is problems of the
peripheral and central nervous systems, and their connection to the senses.
Neurotologist: An otologist who specializes in the nervous
system related to the auditory and vestibular systems.
Newborn hearing screening: A program in place in many hospitals
that allows a child's hearing to be evaluated immediately after the baby is
NIHL: (see Noise-Induced Hearing Loss.)
Noise: Physically, the production of random, erratic sound
waves. Psychologically, any unwanted sound.
Noise-Induced Hearing Loss: Permanent hearing
loss caused by exposing your ears to loud noise. It may occur from a single
sharp loud sound (e.g. gunshot) or from continued exposure to louder noise over
time (days, months, years). Often your audiogram will initially show a "Noise
Notch" around 4,000 Hz.
Noise reduction rating (NRR): The amount of attenuation possible
from a particular type of hearing protection device.
Non-linear hearing aids: Hearing aids that amplify soft sounds
by a different amount than loud sounds in order to keep the volume comfortable
to the wearer.
Normal hearing: Hearing ranging between -10 dB and 15 dB.
Notetaker: A person who writes notes for a hard of hearing or
deaf person in various settings such as the classroom, meetings, or at the
NRR: (See Noise reduction rating.)
Nystagmus: Involuntary, rapid, rhythmic, back-and-forth movement of the eyes that
may accompany vertigo. This is typically caused by damage to the
system, or to the central nervous system.
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OAE: (See Otoacoustic emissions.)
Objective test procedure: Measurement of hearing sensitivity
based on predictions made from physiologic responses such as ABR. The child's
participation is not required.
Occlusion effect: A change in the acoustical properties of the
ear that results from the physical presence of a hearing aid in the ear canal.
The result is that the person feels like they are talking inside a barrel—natural
sounds seem muffled. Some modern hearing aids can largely overcome the occlusion
effect by using "open fit" ear molds.
Occupational Safety and Health Agency (OSHA): Responsible for
administering industrial safety standards set by the Occupational Safety and
Health Act. This includes safe noise levels.
Octave: A two-to-one relationship between frequencies. Thus 1000
Hz is one octave above 500 Hz.
OME: (See Otitis media with effusion.)
Omni-directional microphone: This is the traditional microphone
that is built into hearing aids. It picks up sounds from all directions.
Open Fitting: Hearing aids that use open
fit ear molds. These ear molds fit loosely in the ear canal and thus permit
natural sounds to enter and the louder low frequency sounds from the hearing aid
to escape thus preventing the distorted and muffled
Open-platform hearing aid: A digital hearing aid that can be set
for different hearing losses and also has he potential to be reprogrammed to
code or filter speech in ways that may not even have been invented yet.
Oral deaf education: An approach based on the principle that
most hard of hearing and deaf people can be taught to listen and speak with
early intervention and consistent training to develop their hearing potential.
The goal is for these children to grow up to become independent, participating
citizens in mainstream society. Also known as Auditory-oral education.
Oral interpreter: A professional interpreter who sits facing a
person with hearing loss while silently repeating/rephrasing what a speaker is
saying using good lip/facial movements and modifying some difficult-to-see words
to make it easier of the hard of hearing person to speechread.
Oral transliterator: (Same as Oral interpreter.)
Organic hearing loss: A hearing loss caused by a physical
condition in contrast to a Functional hearing loss.
Organ of corti: That part of the cochlea containing the
Oscillopsia: Oscillating or bouncing vision caused by excessive
motion of an image on the retina. Oscillopsia results when the
is destroyed or severely damaged.
OSHA: (See Occupational Safety and Health Agency.)
Ossicles: (OSS-ih-kulls) General term referring to any small bone, but
used to refer to the three tiny bones (hammer,
anvil and stirrup) in the
Ossiculoplasty: Surgery to repair or replace one or more of the
bones in the middle ear.
Otalgia: Ear pain.
Otitis: (oh-TITE-is) An inflammation involving some portion of the outer, middle or
Otitis externa: Infection (inflammation) of the outer part of the ear
extending into the ear canal. It may be
accompanied by pain, swelling and secretions. Sometimes referred to as
Otitis media: Inflammation of the tissue lining the middle-ear
cavity. Often resulting in infection (fluid) in the middle ear. It occurs when the
Eustachian tube becomes blocked and the fluid that
builds up in the middle ear becomes infected. Usually results in a temporary
conductive hearing loss. Common in children. Children with recurrent attacks may
have fluctuating hearing loss and may be more at risk for acquiring permanent
Otitis media with effusion (OME): Inflammation of the middle ear
with an accumulation of fluid behind the eardrum in the
middle ear space.
Otoacoustic emissions (OAE): Inaudible, but measurable, sounds
created by the vibrations of hair cells in the cochlea, which bend with the
movement of fluid. OAEs are measured with a sensitive microphone placed in the
ear canal. OAEs are used by audiologists as a test of inner ear (cochlear) function.
Otoconia: small crystals of calcium
carbonate that adhere to the gelatinous membrane in the
utricle and saccule. Sometimes called otoliths.
Otolaryngologist: A doctor trained to specialize in diseases of the
ear, sinuses, mouth, throat, larynx and other structures of the head and neck. Commonly called an ENT—ears,
nose and throat doctor.
Otolaryngology: The medical specialty that deals with problems
of the ear, nose, throat, head and neck.
Otolithic crisis of Tumarkin: A type of
drop attack without vertigo in which the person regains
their balance in a few minutes without other side effects. Sometimes used of
drop attacks due to Meniere's disease.
Otoliths: (See Otoconia.)
Otologist: (oh-TALL-oh-jist) An otolaryngologist who has completed a specialty
fellowship focused on ear disorders. Otologists complete over 10 years of
medical training and a specialized otology training fellowship prior to entering
Otology: The medical specialty that deals exclusively with ear
and hearing problems.
Otorhinolaryngologist: (The same as an
Otorrhea: A purulent discharge (puss) draining from the
Otorrhagia: Bleeding from the ear canal. Ear hemorrhage.
Otosclerosis: (OH-toe-sklair-ROW-sis) An inherited
genetic condition that causes abnormal spongy bone growth on the tiny bones in
the middle ear and in the bone surrounding the
oval window. Often this results
in the stirrup (stapes) becoming fixed to the oval window of the
Because the stapes no longer vibrates freely, this causes a progressive
conductive hearing loss. If the otosclerosis eventually invades the
(cochlear otosclerosis), the result is additional (sensorineural) hearing loss.
Otoscope: (OH-toe-scope) A special combination flashlight/magnifying glass used
for examining the ear canal and eardrum.
Ototoxic: (oh-toe-TOX-ick) Refers to any chemical or medication (drug) that is potentially
harmful to the auditory system—especially to the cochlear and
and associated nerves—concerned with hearing and balance. Ototoxic medications may aggravate an existing
hearing problem or cause new hearing problems. For a more
in-depth understanding of ototoxic
drugs, read this article.
Outer ear: The external portion of the ear that collects sounds
waves and directs them into the ear. The outer ear consists of the
pinna and the
Oval window: The membrane between the middle and inner ear where
the stirrup (stapes) bone sits. The footplate of the
stirrup pulsates with the sound
vibrations in the middle ear and transmits them into the fluid of the
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Palinacusis (Palinacousis): Also called
Auditory Perseveration. Palinacusis comes from the Greek words "palin" (again)
and "akouein" (to hear). It is a rare condition in which sounds (words) repeat
again, or many times, after the original sound has stopped.
Paracusis: Impaired hearing. Hearing loss. Also used to refer
to auditory illusions or auditory hallucinations. A disorder in the sense of
Paracusis duplicata: (See Diplacusis.)
PDR: (See Physicians' Desk Reference.)
Perilymphatic fistula: A tear in the oval
or round windows separating the middle ear from the inner ear allowing perilymph
to drain into the middle ear. This can cause hearing and balance problems
sometimes similar to Meniere's disease.
Peri-lingual: Around the time of acquiring language.
Perforated eardrum: An eardrum that has ruptured or has a hole
in it. The fancy term is tympanic membrane perforation. This is commonly a
result of a middle ear infection, and is often
indicated by pain, bleeding or discharge.
Permanent threshold shift (PTS): A permanent worsening of
hearing due to noise exposure.
Perseveration, Auditory: (See Palinacusis.)
PE tube: (See Pressure equalization tube.)
Phoneme: The smallest unit in a language
that is capable of conveying a change in meaning. For example, the "m" in "mat"
and the "b" in "bat." There are 41 phonemes in the English language.
Phonophobia: A fear of sound, or
specific sounds. Phonophobia can be defined as abnormally strong reactions of
the autonomic and limbic systems resulting from enhanced connections between the
auditory and limbic systems, but do not involve a significant activation of the
auditory system. The strength of the person’s reaction is only partially
determined by the physical characteristics of the upsetting sound and is
dependent as well on the person’s previous evaluation and recollection of the
sound (e.g., sound as a potential threat, and/or the belief that the sound can
be harmful), the person’s psychological profile and the context in which the
sound is presented. (See also Misophonia.)
Physicians' Desk Reference (PDR): The main drug reference book
used by doctors, pharmacists and hospitals in the USA.
Pidgin signed English (PSE): A form of signing that uses
Sign Language signs for the most part, but signed in English word order. People
that are hard of hearing, if they sign, generally use PSE to supplement their
oral communication. (See also Signed English.)
Pinna: (PIN-uh) The external or outer ear (auricle).
Pink noise: In contrast to
white noise, pink noise has more energy in the lower
frequencies. Since pink noise has relatively more bass than white noise, it
sounds more natural to the human ear—more like the roar of a waterfall than like
the higher-pitched hissing sound of white noise. As a result, it is sometimes
used to replace the white noise used in tinnitus maskers and in Tinnitus
Retraining Therapy. More technically, pink noise is filtered to give equal power
per octave or equal power per 1/3 octave. Since the number of Hz in each
successive octave increases by two, this means the power of pink noise per Hz of
bandwidth decreases by a factor of two or 3 dB per octave.
Pitch: The subjective impression of frequency.
Placebo: A "medicine" (sometimes called a "sugar pill")
that—unknown to the patient—has no active medicinal ingredients. It is used in
drug studies to compare the efficacy of a new drug to no treatment at all
without the patient being aware of which "treatment" they are receiving.
Platinum Sound Processor (PSP): The body worn
sound processor portion of a cochlear implant made by Advanced Bionics. It is
basically equivalent to the Harmony BTE cochlear implant
Play audiometry: (See Conditioned audiometry.)
Post-lingual: After acquiring language.
Post-lingually deafened: Deafness (hearing loss) that occurs
after language has been acquired.
Posturography: A test that measures how you maintain your
balance when one or more of your senses is blocked.
Potentiation: The interaction between two drugs such that the
pharmacologic response is greater than the sum of the individual responses to
each drug. For example, taking two ototoxic drugs at the same time may cause
a much more severe side effects to your ears than would be the case if you had taken
the same drugs, but at different times. A synergistic effect.
Pre-lingual: Before acquiring language.
Pre-lingually deafened: A person who is either born deaf or who
lost his hearing early in childhood, before acquiring language.
Presbycusis (Presbyacusis): (prez-bee-KOO-sis) Gradual hearing loss, especially in the high
frequencies, due to aging.
Pressure equalization tube (PE): A small tube that is surgically
inserted in the eardrum to equalize the pressure between the
middle ear and the
ear canal and to permit drainage. PE tubes are used when an
tube is not working properly or is clogged up—typically from a middle ear
infection. Also called a tympanostomy tube, myringotomy tube or a grommet.
Profound hearing loss: A hearing loss ranging between 91 and 120
dB. This is essentially a total hearing loss.
Programmable hearing aid: Although
digital hearing aids are
sometimes referred to as being programmable—and they are—the term programmable
hearing aid is generally used to denote a hybrid hearing aid that has digital
components that allows it to be programmed, but its underlying amplifier is
analog. Sometimes called digitally-programmable analog hearing aids.
Proprioceptive system: (proh-pree-oh-SEP-tiv) One of the three
separate balance systems in your body. It consists of nerve sensors in the
muscles, tendons and joints, especially in your legs, ankles and feet, that help
you to keep your balance. The other two systems are your visual system and your
vestibular system in your inner ears. When you vestibular system is damaged,
your proprioceptive system works with your visual system to give you some
semblance of balance.
PSE: Pidgin signed English. (See Signed English.)
PSP: (See Platinum sound processor.)
PTA: See Pure tone average.)
Pure tone: A single frequency used by audiologists to evaluate
Pure tone air conduction audiometry: Measurement of hearing
thresholds to pure tones presented through earphones or ear inserts.
Pure tone audiogram: An audiogram based on listening to pure
tones (the normal situation) as opposed to listening to speech.
Pure tone audiometer: An instrument for generating pure tone
sounds at different frequencies.
Pure tone average (PTA): The average of your hearing
loss at the following 4 test frequencies—500, 1,000, 2,000 & 4,000 Hz. The PTA
is expressed in decibels (dB).
Pure tone bone conduction audiometry: Measurement of hearing
thresholds to pure tones presented from a small vibrator placed against the
Pure tone screening: Test used to determine hearing sensitivity
to pure tones at a fixed hearing level, typically 20 dB HL.
Pure tone testing: This test measures the softest level a person
can hear at a number of different pitches.
Pure tone threshold audiometry: Determining the softest level a
pure tone can be heard about 50% of the time.
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Real ear measurement: A testing technique used to measure the
sound levels produced by a hearing aid while in the are canal. A tiny probe
microphone is placed in the ear canal ahead of the hearing aid. Real ear
measurement evaluates how well a hearing aid is producing the
amplification and quality of sound it should when it is actually working in the
Real-time captioning: The process of producing and projecting
onto a screen verbatim dialogue as typed by a captionist. It provides clear,
accurate print that is easily visible to people in large audiences. Commonly
Receiver: The name for the tiny speaker inside the hearing aid.
(logically it should be called the transmitter as it transmits sound, not
Receptive language: Understanding language. This includes memory
and understanding what is heard (or seen in the case of sign language).
Therefore, receptive language relies on hearing or seeing.
Recessive genetic condition: Inherited condition in which both
parents carry an abnormal recessive gene. More technically, where both genes of
a gene pair are required to produce a physical characteristic (such as hearing
loss). Recessive characteristics are passed only if both parents have the same
recessive gene. Thus each child born to a parent with the same recessive genes
for hearing loss will have a 25% chance of being hard of hearing; a 50% chance
of carrying the gene without having any hearing loss, and a 25% chance of not
having a hearing loss and not carrying the recessive gene.
Recruitment: (re-KROOT-ment) The abnormally greater increase in the
sensation of loudness in response to increased sound intensity as compared with
a normal ear. In practical terms, if you have recruitment, you perceive certain
louder sounds as much louder than normal, and they often hurt. Recruitment is
one result of the greatly-reduced dynamic range found in people with
sensorineural hearing losses. For a more
in-depth understanding of recruitment, read
Relay service: Service that enables text telephone (TTY) users
to communicate with non-text telephone users by way of a relay service
Residual hearing: The amount of measurable, usable hearing left to a
person with a hearing loss.
Residual inhibition: An effect that can occur in which
is reduced or suppressed for a period of time following hearing aid or
masker use. This inhibition may last from a few seconds to a few hours and
sometimes even longer.
Resonance: (REZ-oh-nance) The vibration of an object or a body
of air where certain pitches are made louder. This is the effect noted when
blowing over the top of a bottle.
Reverberation: The prolonging of a sound after the sound source
has ceased. An echo within a room. Reverberation is caused by a lack of sound
absorption materials on the walls, floor and ceiling.
Reverse-slope hearing loss: A rare kind of hearing loss where
the hearing loss is the reverse of most sensorineural hearing losses. With a
reverse-slope loss, the hearing loss is greater in the low frequencies and the
person may have normal or near normal hearing in the very high frequencies.
People with severe reverse-slope losses have normal or near-normal speech in
spite of their degree of hearing loss because they hear the high-frequency
consonants so well.
Rotation test: A test that monitors your eye movements in
relation to your body rotation.
Rubella: A viral infection characterized by fever and a skin
rash resembling measles. If a pregnant woman gets Rubella (German measles), it
may result in sensorineural hearing loss in the unborn child.
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Saccule: A chamber in the
vestibular labyrinth that helps
monitor the position of your head in relation to the ground. The saccule is
responsible for detection of vertical movement.
SAS: (See Simultaneous analog stimulation.)
SAT: (See Speech awareness threshold.)
SD: Sudden deafness. (See Sudden sensorineural hearing
SDT: Speech detection threshold. (Same as Speech awareness
Selective amplification: The general method used for fitting
hearing aids in which more power is provided at the pitches where a person has
greater hearing loss and less power is provided at the pitches where the hearing
is closer to normal.
Semicircular canal: Any of the three tubes that form the
vestibular labyrinth in the inner ear. The canals are filled with fluid and
contain hair cells sensitive to fluid movement, which assist with your sense of
Sensitivity control: In cochlear implants, the sensitivity control
determines how sensitive the microphone is. High sensitivity settings
cause the microphone gain to increase. This can be good in a quiet
environment, but in a noisy environment, it results in poor loudness
relationships between soft and loud sounds. The general rule of thumb is to set
the sensitivity about halfway.
Sensorineural hearing loss (SHL, SNHL): (sen-sor-ee-NOOR-al) A hearing loss caused by damage
(abnormal function) of the cochlea and/or auditory nerve. Often called "nerve
deafness." Typically a sensorineural hearing loss is the result of damaged or
dead hair cells (nerve endings) in the inner ear. More than 90% of adults with
hearing loss have this kind of hearing loss.
Serous otitis media: Inflammation of the middle ear with an
accumulation of thin, watery (serous) fluid.
Severe hearing loss: A hearing loss ranging between 71 and 90
Service coordinator: The person selected by an early
intervention team and designated in an IFSP to coordinate and facilitate early
intervention services and integrate the family into the process. The service
coordinator must demonstrate understanding of the laws and the nature of the
Service provider: A public or private agency designated to
provide early intervention services for an eligible child and the child's family
in accordance with an approved IFSP.
SHL: (See Sensorineural hearing loss).
Signal-to-noise ratio: The relationship of a primary signal (a
person talking) to
the level of the ambient background noise. People with hearing loss need a much better
signal-to-noise ratio than people with normal hearing.
Signed English: A form of sign language that uses signs in
English word order, often with added suffixes and prefixes that are not present
in American Sign Language. Signing Exact English and Seeing Essential English
are two examples.
Sign language: A manual system of communication by which
concepts and language are represented visually through hand movements,
gestures and facial expressions rather than spoken words. In the United States and Canada, the
most common signed language is American Sign Language (ASL). Most hard of
hearing people that learn some sign (not that many do in the first place) typically
use signed English (pidgin signed English) to supplement speech when
communication becomes difficult.
Silhouette: An adapter, placed behind the ear and used with a
hearing aid equipped with a telecoil. It works similar to a neckloop or
Simultaneous analog stimulation (SAS): A software speech
running cochlear implants. The SAS speech strategy feeds current to all of the electrodes all the
time, thus giving continuous stimulation along the entire length of the
electrode array. This is an analog stimulation, meaning that the current levels
at each electrode are smoothly increased or decreased rather than switched on or
off like in CIS.
Ski-slope hearing loss: The shape of your hearing loss as
displayed on your audiogram. If you have a ski-slope hearing loss, your low
frequency hearing is normal or near normal. Your hearing loss quickly drops to
profound by the mid to high frequencies. It looks like a steep ski-slope from
the left side of your audiogram.
Slight hearing loss: A hearing loss ranging between 16 and 25
SLP: (See Speech-language pathologist.)
SNHL: (See Sensorineural hearing loss.)
Sound bore: A channel through the earmold where sound is
received from the hearing aid and delivered to the ear canal.
Sound field system: An FM system that has a small loudspeaker
near the listener to amplify the speaker's voice. The speaker wears a wireless
FM microphone. Sound field systems used in classrooms may have several
loudspeakers focused on different parts of the classroom so all students can
Sound Pressure Level (SPL): Sound pressure level
is the loudness of sound when measured by
sound meters. Sound meters are calibrated in dB SPL. This is because the
condenser microphones used in sound meters are sensitive to changes in sound
pressure in the air, just as our ears are. The SPL scale measures the amplitude of sound based on the pressure of the air
waves reaching the microphone of the sound meter. Since human ears are not
equally sensitive to all frequencies of sound, perfect (normal) hearing would
plot as a wavy line, not a straight line. This makes it hard to determine
whether a person has a hearing loss. Thus, human hearing is normally measured,
not using the SPL scale, but the HL (hearing level) scale. (See
Speech awareness threshold (SAT): The lowest hearing level in
decibels at which a person can detect the presence of speech. Also knows as the
speech detection threshold (SDT).
Speech detection threshold (SDT): (See
Speech frequencies: Those frequencies within the 200 to 6000 Hz
area that are most important for hearing and understanding speech.
Speech intelligibility: The ability to be understood when using
speech. As hearing loss increases, typically speech intelligibility decreases.
Speech-language pathologist (SLP): A health care professional (minimum
of a Masters degree in Speech-language pathology) whose
professional practice includes the evaluation, rehabilitation and prevention of
speech and language disorders. Speech and language delays are frequently seen in
children with hearing losses.
Speechreading: Interpreting the spoken message by
recognizing the movements of the lips, jaws and tongue as well as using
additional cues such as body language, gestures and facial expressions. In
addition a speechreader uses what he knows about the elements of sound, the
structural characteristics of the language, the topic, and the context to figure
out what the person is saying. Formerly called lipreading.
Speech perception: The ability to recognize speech when it is
presented at suprathreshold levels (levels loud enough to be heard).
Speech processor: The circuitry in
the external part of a cochlear implant that converts analog signals from the
microphone into digital signals which the brain understands.
Speech reception threshold (SRT): (Same as Speech recognition
Speech recognition threshold (SRT): The faintest level at which
a person can understand simple two-syllable words (spondee words) 50% of the
time. Also known as the Speech reception threshold (SRT), Speech threshold (ST)
or Spondee threshold (ST).
Speech threshold (ST): (See Speech recognition threshold.)
SPL: (See Sound Pressure Level.)
Spondee: A two-syllable word that has
equal stress on both syllables. Some examples of spondee words include baseball,
cowboy, hotdog, icecream and railroad. Spondee words are used in
Speech Recognition Threshold (SRT) testing.
Spondee threshold (ST): (See Speech recognition threshold.)
Squealing: The feedback sound a hearing aid
makes when it does not fit tightly in the ear canal. Often the hard of hearing
person does not hear this sound, but it sure annoys the people nearby.
SRT: (See Speech recognition threshold.)
SSEP: (See Steady state evoked potentials.)
SSHL: (See Sudden sensorineural hearing loss.)
SSNHL: (See Sudden sensorineural hearing loss.)
ST: Speech threshold and Spondee threshold. (See Speech
Stapes: The third (and smallest) of the three middle ear bones.
It is commonly called the stirrup. It is the smallest bone in our bodies.
Stapedectomy: A surgical procedure to treat otosclerosis that
removes all or part of the stapes (stirrup) that has been fixed in place by otosclerosis, and
replaces it with a prosthesis.
Steady state evoked potentials (SSEP): An objective measure of
hearing that requires no participation from the child. SSEP provides detailed
information about the child's hearing acuity. This is a very new measure hat
does not yet have widespread availability.
Stetoclip: A device resembling a stethoscope, but used for listening
to a hearing aid through a clear plastic tube that attaches to the hearing aid.
Stirrup: The third (and smallest) of the three middle ear bones.
Technically knows as the stapes. It is the smallest bone in our bodies.
Sub-clinical hearing loss: A hearing loss above 8,000 Hz. It can
only be detected using a special audiometer calibrated to test hearing in the
frequencies between 8,000 and 20,000 Hz. Conventional hearing testing only tests
those frequencies between 125 and 8,000 Hz. Many ototoxic drugs cause
sub-clinical hearing loss, at least in the beginning. That is why sub-clinical
testing is so important, yet it is seldom done.
Sudden deafness (SD): (See Sudden sensorineural hearing loss.)
Sudden hearing loss: (See Sudden sensorineural hearing loss.)
Sudden sensorineural hearing loss (SSHL, SSNHL): Hearing loss in the
inner ear that occurs all at once or within only a few days due to such causes
as an explosion, a viral infection or the side effect of some
Suprathreshold levels: Sound levels loud enough to be heard.
Swimmer's ear: (See Otitis externa.)
Syndromic hearing loss: A hearing loss that is accompanied by
additional physical characteristics such as blindness, physical deformities or
mental retardation. It may also involve other organs.
Synergistic: A reaction where the total is more than the sum of
the individual parts. For example, noise and certain drugs have a synergistic
effect on hearing loss. Assume that a given amount of noise normally causes 1
unit of hearing loss. Also, assume that a given drug normally causes 2 units of
hearing loss. Therefore, if you were exposed to both the noise and the drug, you
would expect to have 3 units of hearing loss. However, in this hypothetical
example, when tested, you find you have 7 units of hearing loss. The extra 4
units above what you would have expected by adding up the two figures, is caused
by the synergistic action of noise and ototoxic drugs working together.
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T-coil: (See Telecoil.)
TDD: Telecommunication device for the deaf. (See Teletype.)
Telecoil: A tiny coil of wire built into many hearing aids that
allows the hearing aid to pick up the magnetic fields emitted by telephones, various assistive listening
devices, or induction room loops. Sometimes referred to as "t-switch" or
Telecommunication device for the deaf: This term has
fallen out of favor as the Deaf community never liked it. They use TTY, the
abbreviation for teletype instead. (See Teletype.)
Telecommunications Relay Service (TRS): A
telecommunication system that uses operators (called
Communications Assistants [CA]) to facilitate telephone calls to or from
people who are deaf or have limited hearing and also people with speech
disabilities. This includes text to voice (TTY),
Voice Carry Over (VCO), Captioned Telephone
Service, Video Relay Service (VRS) and several other
Telemic: An optional accessory to the TEMPO cochlear implant by Med-El
that allows the user to take advantage of two features--a built-in telecoil for
accessing certain assistive listening devices, or an external microphone.
Teletype (TTY): A text telephone that allows people with very limited
hearing or no hearing to communicate over the phone. Rather than speaking into
the phone and listening, a person types and reads. It uses Baudot code which has
largely been rendered obsolete by the widespread use of digital technology.
Temporary threshold shift (TTS): A temporary (lasting less than
a day) hearing loss due to exposure to loud sounds. Repeated exposure to sound
loud enough to cause TTS can eventually lead to permanent hearing loss.
Text telephone: (See Teletype.)
Threshold: In audiometry, the softest sounds (usually pure tones
or speech) a person can detect 50% of the time. The term is used for both speech
and pure tone testing.
Tinnitus: (TIN-ih-tus or tih-NIGH-tus) A sensation (subjective perception) of various
(phantom) noises in the ears. Tinnitus is variously described as ringing, roaring,
clicking, humming, buzzing, swishing, whooshing, clanging, shrieking and other similar sounds
that seems to originate in your ears or head. It is not a disease, but a symptom
of various abnormal underlying condition it he auditory system. It is often
associated with hearing loss and exposure to loud noise. For a more
in-depth understanding of tinnitus, read this
Tinnitus masker: A hearing aid-like device that produces white
noise the purpose of which is to cover up the internal tinnitus sounds.
Tinnitus Retraining Therapy (TRT): An
effective treatment for tinnitus where the person with tinnitus undergoes a
two-part treatment which includes wearing a white-noise generator set to a bit
below the level of their tinnitus, and directive counseling where the person
learns about tinnitus and how to break their emotional attachment to it.
Tonotopic organization: The inner ear and the auditory area of
the brain and central nervous system are arranged in pitch order, from low to
high. Sounds of different pitches are processed by different hair cells in the
cochlea, nerve fibers or brain synapses. The cochlear implant, therefore, is
designed to present pitch information to the areas of the cochlea that are
"tuned" to be sensitive to those pitches.
Total communication: An approach to communicating with severely
and profoundly hard of hearing people that includes simultaneous use of signing
and speech (simultaneous communication or sim-com), sometimes supplemented with
Transient Spontaneous Tinnitus (TST): A short,
usually high-pitched tinnitus lasting for a few seconds. Almost everyone hears
this kind of tinnitus occasionally.
Transition: Occurs at the age of three when a child and family
are no longer eligible for services under Part C of the Individuals with
Disabilities Education Act (IDEA). This is a collaborative process involving
families, Part C and Part B programs and, as appropriate, other community-based
preschool programs to ensure uninterrupted provision of appropriate services.
Planning and decision-making must occur well in advance of the child's third
TRS: (See Telecommunications Relay Service.)
TRT: (See Tinnitus retraining therapy.)
TST: (See Transient Spontaneous Tinnitus.)
T-switch: (See Telecoil.)
TTS: (See Temporary threshold shift.)
TTY: (See Teletype.)
Tumarkin, Otolithic crisis of: (See Otolithic
crisis of Tumarkin).
Tympanic: Referring to the middle ear.
Tympanic membrane: The eardrum. It separates the outer ear from
the middle ear and is conducts sound to the middle ear. More technically, the
eardrum is a thin, taut,
concave, pearly-white membrane
that covers the entrance to the middle ear. It vibrates in response
to incoming sounds, which are then transmitted to the middle and inner ear.
Tympanogram: A measure of the mobility of the eardrum. A
tympanogram is a graph that shows how well the middle ear pressure
regulating system is working, whether the eardrum is intact and how well it
moves. It can be used to identify middle ear disorders that require medical
Tympanometer: Instrument used to screen for middle-ear disorders
such as otitis media.
Tympanometry: A test that checks the function of the eardrum and
middle ear by measuring whether the eardrum moves normally when varying amounts
of air pressure are applied to the ear.
Tympanoplasty: Surgery to repair or replace a damaged eardrum.
Tympanostomy tube: (see Pressure equalization tube.)
Tympanum: The middle ear cavity.
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UCL: (See Uncomfortable loudness level.)
Uncomfortable loudness level (UCL): The volume at which sounds
become uncomfortably loud. Any further increase in volume would hurt.
Unilateral hearing loss: Hearing loss in one ear only.
Unilateral hearing loss adversely affects the educational process in a
significant percentage of students who have it.
Utricle: A chamber in the
vestibular labyrinth that helps
monitor the position of your head in relation to the ground. The utricle is
responsible for detection of horizontal movement.
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VCO: (See Voice Carry Over.)
Vent: A small hole through a In-the Ear hearing aid or
to allow air into the ear. The size of the vent can be modified to change the
acoustical properties of a hearing aid.
Ventilation tube: A small tube inserted into the eardrum that
relieves the pressure of a middle ear infection by allowing fluid to drain from
the middle ear. (Also called a Pressure equalization tube.)
Vertigo: Vertigo is the illusion or sensation of movement when
none is present. If may feel like you are spinning around, or that the room is
spinning around you. Frequently vertigo is accompanied by feelings of imbalance
and/or nausea. Vertigo is a common result of damage to the balance system of the
inner ear. Less often, it is caused by abnormal conditions in the central
nervous system. Many ototoxic drugs can cause vertigo.
Vestibular aqueduct: A narrow bony canal
(aqueduct) that runs through the skull, connecting the inner ear (vestibule) to
the cranial cavity—hence its name. Running through this bony canal is a
membranous tube called the endolymphatic duct which connects the endolymphatic
sac (located between the skull and the brain) and the inner ear. It is filled
with endolymphatic fluid.
Vestibular labyrinth: A structure of the inner ear made up of three
fluid-filled, semicircular tubes (canals) that assist with balance. (See also
Vestibular nerve section: Surgery to cut the
vestibular branch of the 8th cranial nerve. This is done when intractable
vertigo resulting from a condition such as
Meniere's disease becomes debilitating. When this is
done, the person has no balance function in that ear, but no more vertigo
Vestibular rehabilitation: A therapeutic program that uses
exercises to help you regain your sense of balance.
Vestibular system: That portion of the inner ear and the central
nervous system involved with the sense of balance. It includes the semi-circular
canals, saccule, utricle and vestibule. This system controls your equilibrium (balance) and
stabilizes your eyes in space. It works together with your brain to sense,
maintain and regain your balance and a sense of where your body and its part are
positioned. It regulates movement (walking, running, etc.) and keep objects in
visual focus as the body moves. Many ototoxic drugs can damage your vestibular
system. This can give rise to a whole host of balance-related problems.
Vestibulocochlear nerve: (See Eighth cranial nerve.)
Video Relay Service (VRS): A form of
Telecommunications Relay Service which allows a user with a
videophone to connect with a TRS Communications Assistant (CA)
who uses American Sign Language (ASL) to facilitate telephone
calls between people who use ASL (typically deaf people) and others.
Visual reinforcement audiometry (VRA): A hearing testing
procedure for children in which the child's responses to sound are reinforced
with a visual event (such as a toy that moves). The audiologist attempts to
condition the child to look for the toy when a sound is heard, thus providing a
method for testing the hearing of small children. This procedure is most
appropriate for children in the 6-month to 3-year age range.
VNS: (See Vestibular nerve section).
Voice Carry Over (VCO): Voice Carry Over
allows people who are deaf or have limited hearing to speak directly to hearing
people. When a standard telephone user speaks to you, a Communication Assistant
(CA) serves as your "ears" and types everything said where it is displayed on
your TTY or special VCO phone.
Volume control: A device for increasing or decreasing the volume
(gain) of a hearing aid or assistive listening device.
VRA: (See Visual reinforcement audiometry.)
VRS: (See Video Relay Service.)
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Wavelength: Wavelength is the distance between sound
(compression) waves and is directly related to frequency—the higher the
frequency, the shorter the wavelength. In fact, if you divide the speed of sound
in air by the frequency of the sound you are interested in, the result is the
wavelength. Human hearing ranges from 20 to about 20,000 Hz. The corresponding
wavelengths are 56.3 feet to 0.67 inches.
Wax: (See Ear wax.)
WD: (See Word discrimination testing.)
Whistling: The feedback sound a hearing aid
makes when it does not fit tightly in the ear canal. Often the hard of hearing
person does not hear this sound, but it sure annoys the people nearby.
White noise: White noise is noise whose
amplitude is constant throughout the audible frequency range. The sound of white
noise is a high-pitched hissing, similar to the sound of steam escaping from an
overheated radiator. White noise is produced by a random noise generator, and is
used in tinnitus maskers and in Tinnitus Retraining Therapy. More technically,
white noise is defined as sound with equal power per Hz in frequency. Since each
successive octave of frequency has twice as many Hz in its range, the power in
white noise increases by a factor of two for each succeeding higher octave.
Thus, white noise increases by 3 dB per octave in power. Incidentally, our ears
hears the high frequency hissing in white noise more than the lower-frequency
sounds since the ear is more sensitive to high frequencies. This high-frequency
sound tends to grate on the nerves more than lower frequency sounds, so now they
are beginning to use the more natural-sounding pink noise
in tinnitus maskers and related devices instead of white noise.
Wide dynamic range compression: A special circuit in some
hearing aids that compresses a wide range of sounds into a narrower range. This
makes soft sounds easier to hear and makes loud sounds more comfortable for
Word discrimination testing (WD): The older term for what is now called "Word
recognition testing." (See Word recognition testing.)
Word recognition testing (WR): A test that determines how well you
can understand single-syllable words when they are heard at your most
comfortable level. The results are expressed as a percentage. (See also
WR: (See Word recognition testing.)
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