Glossary  of Hearing Loss and Other Terms
Related to Ears

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Numbers

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 nerves overproduce.

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 after birth.

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 ototoxic drugs.

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.

Air conduction:  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 syntactical rules.

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 attachment.

Amplitude:  The physical intensity of a sound. (Subjective impression of "loudness.")

AN:  (See Auditory neuropathy)

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.

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 FM systems, 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 signal.

Audio-coil:  (Same as T-coil and telecoil.)

Audiogram:  A graphic representation of a person's hearing loss. More technically, a graph of a person's hearing threshold levels (in decibels) 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 or echoes.

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 communication problems.

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 the electrical 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 (AN)/Dysyncrony:  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.

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 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 room.

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 rehabilitation.)

Aural rehabilitation:  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 style.

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 speech.

BAEP:  Brainstem auditory evoked potential.  (See Auditory 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 cochlea nearest the middle ear. The basal region detects high frequency sounds and sends them to the brain.

Basilar membrane:  The central membrane in the cochlea upon which the hair cells rest. The basilar membrane is contained within the Organ of Corti.

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.

Benign 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.

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: Referring to both ears.

Binaural hearing: Hearing with both ears.

Binaural hearing aids:  Hearing aids worn in both ears at the same time.

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.)

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 response testing.)

BSER:  Brainstem evoked response.  (See Auditory brainstem response testing.)

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 ear canal.

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.

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 normally.

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 Accessible Technologies.)

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 auditory nerve.

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 nerve.")

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 CIS and SAS.

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 Audiological evaluation.) For a more in-depth understanding of what a complete audiological evaluation entails, read this article.

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 invisible.

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 audiometry.)

Conditioned play audiometry (CPA):  (Same as Conditioned audiometry.)

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 or blocks 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 media).

Congenital hearing loss:  A hearing loss present at birth, or associated with the birth process, or which develops in the first few days of life. It may or may not be hereditary.

Continuous interleaved sampling (CIS):  A software speech strategy for 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 Ipsilateral.)

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 strategies.)

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 said.

CPS:  (See Compendium of Pharmaceuticals and Specialties.)

CROS hearing aid:  (See Contralateral Routing of Sound Hearing Aid.)

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 language.

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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 (loudness) 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.

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 Programmable hearing aid.)

Digital signal processing (DSP):  Improving hearing with manipulation by mathematical formula of a sound signal that has been converted from analog to digital.

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 directions.

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 BPPV. 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.

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.

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 plugs.

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 cerumen (sir-ROO-men).

Educational audiologist:  An audiologist with special training and experience in providing auditory rehabilitation services to children in school settings.

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, tinnitus, 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 cochlear implant. 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 Auditory 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 audiologist about 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 muscles.

ENG:  (See Electronystagmography.)

ENT:  Ear, Nose and Throat doctor. (See Otolaryngologist.)

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 Large 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 Auditory 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 earmolds.

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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 fullness.

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 Hertz (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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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 ITE aid.

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 telecoil.

HAT:  (See Hearing assistive technology.)

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.

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 help you.
• 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 detailed testing.

Hearing threshold:  The quietest level a person can hear at least 50% of the time under ideal conditions.

Hereditary hearing loss:  Hearing loss that is passed genetically though generations of a family. Hearing loss can be passed by dominant or recessive genes.

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.)

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.

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.

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 Tympanogram.)

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 communication.
• 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 communication.

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 decibels (dB).

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 microphone.

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.

Intonation:  (The same as Inflection.)

Ipsilateral:  On the same side, with reference to a given point. (The opposite of Contralateral.)

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.

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Labyrinth:  (See Vestibular labyrinth and Vestibular system.)

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.

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.

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 cochlear 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 speech 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 vertigo, tinnitus, a feeling of fullness in the affected ear and a fluctuating hearing loss. It is thought to be caused by fluid imbalance in the inner ear.

Meningitis:  A bacterial or viral inflammation that can cause auditory disorders due to infection or inflammation of the inner ear or auditory nerve.

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 ossicles)—malleus (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 CIC and 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.

Mixed hearing loss:  A combination of both sensorineural (inner ear) and conductive (middle ear or outer ear) hearing loss. The audiogram show an air-bone gap of 10 dB or more.

Moderate hearing loss:  A hearing loss ranging between 41 and 55 dB.

Moderately severe hearing loss:  A hearing loss ranging between 56 and 70 dB.

Monaural:  Referring to just one ear, as opposed to binaural—both ears.

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 digital hearing 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 environment."

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 Infrared receiver.

Nerve damage:  Damage to the hair cells (nerve endings) in the inner ear.

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 born.

Noise:  Physically, the production of random, erratic sound waves. Psychologically, any unwanted sound.

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 office.

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 vestibular 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 fells like they are talking inside a barrel. Some modern hearing aids can largely overcome the occlusion effect.

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-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 hair cells.

Oscillopsia:  Oscillating or bouncing vision caused by excessive motion of an image on the retina. Oscillopsia results when the vestibular system is destroyed or severely damaged.

OSHA: (See Occupational Safety and Health Agency.)

Ossicles:  (OSS-ih-kulls) General term referring to any small bone, but mostly used to refer to the three tiny bones (hammer, anvil and stirrup) in the middle ear.

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 inner ear.

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 "swimmer's ear."

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 hearing loss.

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.

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 practice.

Otology:  The medical specialty that deals exclusively with ear and hearing problems.

Otorhinolaryngologist:  (The same as an Otolaryngologist.)

Otorrhea:  A purulent discharge (puss) draining from the ear canal.

Otorrhagia:  Bleeding from the ear canal. Ear hemorrhage.

Otosclerosis:  (OH-toe-sklair-ROW-sis) An inherited dominant 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 cochlea, Because the stapes no longer vibrates freely, this causes a progressive conductive hearing loss. If the otosclerosis eventually invades the cochlea (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 vestibular organs 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 ear canal.

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 inner ear.

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PDR:  (See Physicians' Desk Reference.)

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.

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.

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 American 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 sound processor.

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:  (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 Eustachian tube is not working properly or is clogged up. Also called a Tympanostomy tube.

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 hearing sensitivity.

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 skull.

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 ear canal.

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 called CART.

Receiver:  The name for the tiny speaker inside the hearing aid. (logically it should be called the transmitter as it transmits sound, not receives sound.)

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 this article.

Relay service:  Service that enables text telephone (TTY) users to communicate with non-text telephone users by way of a relay service communications assistant.

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 tinnitus is reduced or suppressed for a period of time following hearing aid or tinnitus 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 loss.)

SDT:  Speech detection threshold. (Same as Speech awareness threshold.)

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 balance.

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 (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 dB.

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 process.

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.

Signal-to-noise ratio:  The relationship of a primary signal (a person talking) to the level