Educate Yourself – Glossary of Terms

Acoustic — Simply means having to do with sound or hearing.

Acoustic Nerve — The auditory nerve that carries hearing information between the cochlea and the brain.

Acoustic Neuroma — A tumor, usually benign, which may develop on the hearing and balance nerves and can cause gradual hearing loss, tinnitus, and/or dizziness.

Acquired Deafness — The loss of hearing that occurs or develops sometime during a person's life but was not present at birth.

Alerting Device — Visual or tactile devices to alert a person who cannot hear to door knocks, telephone rings, fire alarms, etc.

Americans with Disabilities Act (ADA) — The Americans with Disabilities Act of 1990 Public Law 101-336 prohibits discrimination on the basis of disability by public entities.

Amplified Phone — Amplified phones are specifically designed for the hearing impaired, allowing users to turn up the volume as necessary to hear speech clearly. Amplified phones also have features that make it easier to hear high-pitched noises, which many people with hearing loss find challenging.

Amplifier — An electronic device for increasing the amplitude of electrical signals, used chiefly in sound reproduction.

Amplitude — The physical intensity of a sound.

Anvil (Incus) — The second of the three bones in the middle ear.

Apical region — The tip of the snail-shell-shaped cochlea, where low frequency sounds are detected and sent to the brain.

Assistive Listening Device (ALD) — Technical tool to assist people with hearing loss, with or without a hearing aid. It brings the speaker’s voice directly to the ear. Helps to improve the signal to noise ratio in high noise environments and overcomes distance to the speaker in large meeting areas or auditoriums.

Atresia — The absence or closure of the external auditory meatus (ear canal).

Audio Loop (Induction Loop) — Uses electromagnetic waves for transmission of sound. The sound from an amplifier is fed into a wire loop surrounding the seating area (or worn on the listener’s neck) which broadcasts to a telecoil that serves as a receiver. Hearing aids without a T-switch to activate a telecoil can use a special induction receiver to pick up the sound.

Audiogram — A chart onto which the results of a hearing test are graphed. Usually the chart has intensity levels listed on one axis and frequencies (pitches) listed on the other axis.

Audiology — The science of the assessment and management of hearing and balance disorders.

Audiometry — Another name for a hearing test or hearing evaluation.

Auditory Nerve — Eighth cranial nerve that connects the inner ear to the brain.

Auditory Perception — Ability to identify, interpret, and attach meaning to sound.

Auditory Processing Disorder (APD) — Inability of an individual with normal hearing and intelligence to differentiate, recognize, or understand sounds normally.

Auditory Reflex (sometimes called Acoustic Reflex) — A reflex of the middle ear that occurs in response to sound at a certain and variable intensity. It is measured for diagnostic purposes of the auditory system.

Autoimmune Hearing Loss — Hearing loss when one’s immune system produces abnormal antibodies that react against the body’s healthy tissues. May be associated with tissue-attacking disease; such as rheumatoid arthritis or lupus.

Auxiliary Aids and Services — The Department of Justice regulation provides a comprehensive list of auxiliary aids and services required by the ADA to help overcome communication barriers. Examples of auxiliary aids and services are: assistive listening devices, interpreters, notetakers, captioning, etc.

Balance Disorder — Disruption in the labyrinth, the inner ear organ that controls the balance system, which allows individuals to know where their bodies are in the environment. The labyrinth works with other systems in the body, such as the visual and skeletal systems, to maintain posture.

Barotrauma — Injury to the middle ear caused by a rapid change of air or water pressure.

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.

Behind-The-Ear Hearing Aid/BTE Hearing Aid — A style of hearing aid in which the electronic portion of the hearing aid (including battery, microphone, speaker, amplifier, etc.) is located on top of or behind the ear. The electronic portion is connected via a piece of tubing to an earmold, which is in the ear.

Bi-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.

Bilateral — A term used to signify that both ears or both sides of the head are involved (i.e., "He has bilateral hearing loss.").

Bone-Conduction-Thresholds — The lowest level that an individual can hear a pure–tone stimulus presented through a vibrator placed on the mastoid bone or forehead. Bone–conduction threshold testing attempts to assess the ability of the sensory and neural auditory systems without the sound passing through the outer and middle ear.

Brainstem Implant — Auditory prosthesis that bypasses the cochlea and auditory nerve. This type of implant helps people who can’t benefit from a cochlear implant because the auditory nerves are not working.

Captioning — Text display of spoken words, presented on a television or a movie screen, that allows deaf or hard-of-hearing viewers to follow the dialogue and the action of a program simultaneously.

Captioned Telephone — Text of the conversation is displayed on a monitor built into the phone so the person with hearing loss can follow the call. A special phone is required.

CART — (Communication Access Realtime Translation) — CART is the verbatim, near instantaneous conversion of spoken language into text. A stenotype machine, notebook computer and real-time software is used to produce the text. The text is usually displayed either on a screen by a projector connected to the notebook computer, or on a notebook computer or computer monitor. CART is usually utilized by people with hearing loss who use spoken language as a primary mode of communication. However, some culturally Deaf people (whose primary mode of communication is sign language) use CART in situations such as graduate level anatomy classes, as it may be easier to read all of the specific terminology rather than have signs improvised on the spot, or use fingerspelling.

Certified Hearing Dog — A dog that has completed extensive training to alert its owner to a variety of sounds in different environments. These dogs are usually identified by a bright orange leash with black lettering.

Ceruminosis — Increased or excessive earwax buildup.

Cholesteatoma — An abnormal accumulation and pocketing of dead cells in the eardrum, which can often be surgically repaired.

Cochlea — Snail-shaped structure in the inner ear that contains the organ of hearing.

Closed Captions — Text display of spoken dialogue and sounds on TV and videos visible only to those using a caption decoder or TV with built-in decoder chip.

Cochlear Implant (CI) — A cochlear implant is an electronic device that is surgically implanted and worked by directly stimulating functioning auditory nerve fibers in the inner ear. Cochlear implants convert sound waves to electrical impulses and transmit them to the inner ear, providing people with severe to profound hearing loss the ability to hear sounds and potentially better understand speech without reading lips.

Communication Access — Accommodations that provide an environment where persons with hearing loss can communicate.

Compatible Telephone — Generates a magnetic field that can be picked up by turning on a “T-switch” to activate the telecoil in a hearing aid. The Hearing Aid Compatibility Act of 1988 mandates that all telephones manufactured in the United States from 1989 on should be hearing aid compatible.

Computer-Assisted Notetaking — Visual display of the speaker’s words. A notetaker types on a computer keyboard a summary of what is being said. The notes are displayed on a projection screen or monitor.

Conductive Hearing Loss — Hearing loss caused by an abnormal transmission of sound in the outer or middle ear. Most common in children.

Congenital Hearing Loss — The presence of hearing loss at or before birth.

Cued Speech — A sound-based visual communication system which in English uses eight handshapes in four different locations (“cues”), in combination with the natural mouth movements of speech, to make all the sounds of spoken language look different.

Deaf — Describes people who usually have no useful residual hearing and who generally use sign language as their primary mode of communication. This group of people are culturally Deaf and use the uppercase "D" when writing the term. However, people who are audiologically deaf (using a lowercase "d") generally use their residual hearing with speechreading, amplification, hearing aids and/or cochlear implants, and other hearing assistive technology. They may also learn sign language but are oral and don't use it as a primary mode of communication. Based on the age at the time of loss of hearing, people who are deaf are categorized into two groups: congenitally deaf – those who were born deaf; and adventitiously deaf – those who were born with hearing but whose sense of hearing became non-functional later in life through illness, accident or age-related (presbycusis). The term deaf should always be used with a people descriptor; for example, people who are deaf; deaf people. The phrase "the deaf" should not be used. See Glossary for definitions of "hard of hearing" and "hearing loss."

Decibel (dB) — Unit used to express the intensity of a sound wave in logarithmic ratios to the base of ten. Sounds of different frequencies need to be from 0-20 dB in intensity to be heard by normal ears. If more than 20 dB is needed, then further hearing evaluation would be recommended.

Disequilibrium — Any disturbance of balance.

Ear Infection — Presence and growth of bacteria or viruses, usually in the middle ear.

Earwax (Cerumen) — Yellow secretion from glands in the outer ear canal that keeps the skin of the ear canal dry and protected from infection.

Ear Canal — The external auditory meatus. The hole in the temporal bone that tunnels the sound from the pinna to the eardrum (tympanic membrane).

Eardrum — The tympanic membrane. A thin layer of skin that separates the ear canal from the middle ear cavity. The eardrum converts sound waves into vibrations.

Earhook — A portion of a Behind–The–Ear hearing aid that is designed to bend over the top of the ear and connect the aid’s casing to the tubing.

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.

Effective Communication — Term used in the ADA as a standard for access for people with hearing loss. A public accommodation must provide an auxiliary aid or service where necessary to ensure effective communication with individuals with disabilities. The Department of Justice strongly encourages staff of public accommodations to consult with the individuals before providing them with particular auxiliary aids or services.

ENG (Electronystagmography) — A special series of tests utilized to evaluate the vestibular system, during which eye movements are measured electrophysically.

Etiology — In hearing terms, the source or cause of a hearing loss.

Eustachian Tube — A small connection between the throat and the middle ear cavity which in the normal human ear system is utilized to equalize the pressure in the middle ear cavity to the pressure in the atmosphere surrounding the body.

Eustachian Tube Dysfunction — When the tube that connects the throat and the middle ear cavity becomes inflamed or blocked. Eustachian tube dysfunction can lead to negative pressure, fluid in the middle ear, and/or middle ear infections.

Exostosis — A bony growth in the ear canal.

External ear — Part of the auditory system comprised of the pinna and external auditory meatus.

Feedback — The high–pitched whistling sound that can be emitted by a hearing aid when the hearing aid’s microphone picks up its own output, thus re-amplifying itself.

Feedback Suppressor — Technology present in some newer hearing aids that is designed to limit the amount of feedback experienced by hearing aid users. Low-end hearing aids lower gain to reduce feedback, while more advanced hearing aids alter the phase of the signal to control feedback.

Fistula — An abnormal hole or rupture in the window that connects the middle ear cavity and the cochlea, allowing the leakage of inner ear fluid (perilymph) into the middle ear and often resulting in hearing loss and dizziness.

Flat Audiogram — A description of the graph of an individual’s hearing thresholds in which the degree of loss present is similar or equal for low, mid and high frequencies.

FM (Frequency Modulation) — A transmitter which broadcasts the signal by radio waves from the sound source to a receiver worn by the listener. Useful in large indoor or outdoor locations, since it can cover several hundred feet and pass through physical obstructions.

Footplate — Portion of the stapes bone that is attached to the two crura and that sits in the oval window.

Frequency — Cycles per second. The number of vibrations occurring during a second, resulting in the perceived “pitch” of a sound.

Habituation — Term used when you are no longer aware of your tinnitus except when you focus your attention on it.

Hair Cells — Sensory cells of the inner ear, which are topped with hair–like structures (stereocilia), which transform the mechanical energy of sound waves into nerve impulses.

Hard of Hearing — Hard of hearing is a descriptive term used when making the distinction among people with hearing loss; for example, people who are deaf and hard of hearing. People often use the term hard of hearing to describe themselves no matter the audiological level of hearing loss. Typically, people who use residual hearing, amplification and/or hearing assistive technology and who do not use sign language as a primary mode of communication, consider themselves hard of hearing rather than deaf. Generally, people who consider themselves hard of hearing, no matter their level of hearing loss, are committed to participating in the hearing world using speechreading, residual hearing, technology and sometimes sign language. The term hard of hearing is always used with the "people" descriptor as in "people who are hard of hearing" or "hard of hearing people." The term "the hard of hearing" should not be used.

Head-End Decoding — Hotels with in-house television cable systems can provide closed captioning services by head-end decoding. The TV signal at the master antenna (headend) is split and one of the two signals is run through a closed caption decoder. The decoded signal is outputted to an unused TV channel of the in-house cable distribution system. Viewers can have a choice of the same program on a channel with captions or on another channel without captions.

Hearing Aid — An amplification device to assist persons with hearing loss. There are different kinds of hearing aids which are distinguished by how they are worn. They might be In-The-Ear (ITE), In-The-Canal (ITC), Behind-The-Ear (BTE), or on the body. The technology is still imperfect and hearing aids do not correct hearing loss. Newest developments include hearing aids that connect wirelessly to a variety of electronics.

Hearing Dog — See Certified Hearing Dog.

Hearing Loop — A wire that circles a room and is connected to the sound system. The loop transmits the sound electromagnetically. The electromagnetic signal is then picked up by the telecoil by flipping the t-switch in a hearing aid or cochlear implant.

Hereditary Hearing Impairment — Inherited hearing loss that is passed down through the family.

Hearing Loss — Describes someone with any degree of hearing loss ranging from mild to profound. There are 48 million people with hearing loss in the United States accordin go the Hearing Loss Association of America. The term hearing loss can encompass both people who are deaf and people who are hard of hearing. Many people with hearing loss use hearing assistive technology such as hearing aids and/or cochlear implants. A small number who are culturally Deaf use sign language as a primary mode of communication. HLAA mostly uses the term people with hearing loss in descriptive writing and avoids using the term "hearing impaired." Hearing impaired is an audiological term and HLAA avoids using it when referring to an individual's hearing loss. See this Glossary for the definitions of "deaf" and "hard of hearing." The FDA classifies hearing loss as:

20-40dB: Mild
40-70dB: Moderate
70-90dB: Severe
>90dB: Profound

Hyperacusis — Abnormal hearing sensitivity.

Impedance — An object or medium’s resistance to energy flow.  A high-impedance medium will reject energy; a low-impedance substance vibrates more freely.

Impression — A mold of the concha and ear canal made by a hearing healthcare professional to assist the hearing aid manufacturer in producing a custom fit hearing aid that sits in and seals the user’s ear appropriately.

Incus (Anvil) — The middle bone of the ossicular chain.

Induction Coil — The telecoil inside of a hearing aid that is activated by electromagnetic energy coming from a telephone or assistive listening device.

Infrared — Similar to FM except that it uses invisible light waves to transmit sound. Frequently used in theaters.

In–The–Canal (ITC) Hearing Aid — Smaller than an ITE hearing aid, it usually fills up a portion of the ear canal and a small portion of the outer ear. A mini-canal attempts to make the hearing aid even smaller by using a smaller battery.

In–The–Ear (ITE) Hearing Aid — A style of hearing aid in which all the parts of the hearing aid are fit into the concha or bowl area of the pinna and the ear canal.

International Symbol of Accessibility for Hearing Loss — Symbol used to denote communication access. This symbol is an outline of an ear with a slash through it to identify that a room or venue is hearing-accessible. There is also another similar one with a “T” in the lower right-hand corner to identify the room or venue has a wireless hearing assistive technology known as a hearing loop installation connected to a sound system.

Interpreter-Sign Language — Visible movements of hands, body and face that replace the vocal elements of a spoken language. Depending on the communication situation and personal preferences, people who have hearing loss or who are deaf in the United States who use sign language might communicate using the unique grammar of American Sign Language (ASL) or some variety of signing that uses features taken from both ASL and English Sign Language.

Labyrinth — Organ of balance located in the inner ear. The labyrinth consists of three semicircular canals and the vestibule.

Labyrinthitis — Viral or bacterial infection or inflammation of the inner ear that can cause dizziness, loss of balance, and temporary hearing loss.

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.

Lipreading — A skill used by a person with hearing loss to try to understand speech by watching the lips. The term “speechreading” is now recognized as being more descriptive since it includes watching the facial expressions and body language, as well as the lips of the speaker.

Listening Stethoscope — A device used by hearing healthcare professionals to listen to a hearing aid for the purpose of assessing the hearing aid’s performance and adjustments / repairs.

Loop System — A type of assistive listening device that utilizes a small neck or large room loop to set up a magnetic field. The system allows for a transfer of a desired signal, with less background noise interference, to a hearing aid or other device using electromagnetic energy.

Masking Noise — A sound introduced into an ear system for the purpose of covering up an unwanted sound. Masking noises are used during hearing tests to cover up unwanted responses from a non-test ear. Tinnitus maskers also utilize a masking noise to cover up tinnitus.

Mastoid — Hard, bony structure behind the ear. Part of the temporal bone.

Mastoid Surgery — Surgical procedure to remove infection from the mastoid bone.

Malleus — The first of the three middle ear bones. It is the bone touching the eardrum. Commonly called the Hammer.

Ménière’s Disease — An inner ear disorder that can affect both hearing and balance and is usually associated with vertigo (feeling like you’re spinning when you’re really not), hearing loss, roaring tinnitus, and the sensation of fullness in the ear.

Meningitis — Inflammation of the meninges, the membranes that envelop the brain and the spinal cord; may cause hearing loss, including deafness.

Middle Ear — Part of the ear that includes the eardrum and three tiny bones (ossicles) of the middle ear, ending at the oval window that leads to the inner ear.

Mild Hearing Loss — A hearing loss ranging between 21 and 40 dB.

Mixed Hearing Loss — A hearing loss that has both conductive and sensorineural components.


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.

Noise–Induced Hearing Loss — Hearing loss caused by exposure to very loud sounds, either very loud impulse sound(s) or repeated exposure to sounds over the 90-decibel level over an extended period of time that damages the sensitive structures of the inner ear. Learn more about noise-induced hearing loss.

Notetaker — A person who takes notes to enhance understanding for a person with a hearing loss.

On–The–Ear (OTE)/Open Ear Hearing Aid — A more recently developed style of a BTE hearing aid that utilizes a thinner tubing and a placement of the electronics lower down behind the ear for better cosmetic appeal with less occlusion.

Otitis Media — Inflammation of the middle ear caused by infection.

Otoacoustic Emissions — Low-intensity sounds produced by the inner ear that can be quickly measured with a sensitive microphone placed in the ear canal in individuals with normal hearing. Often used to screen the hearing of infants.

Otolaryngologist — Physician/surgeon who specializes in diseases of the ears, nose, throat, and head and neck.

Oral Interpreter — The interpreter silently mouths the words of the speaker so they are visible on the lips. Used when the person with hearing loss uses speechreading to understand the conversation.

Otologist/Neurotologist — An otologist/neurotologist is a board certified otolaryngologist who provides medical and surgical care of patients, both adult and pediatric, with diseases that affect the ears, balance system, temporal bone, skull base, and related structures of the head and neck. The neurotologist is knowledgeable of the basic sciences of hearing, balance, nerve function, infectious disease and anatomy of the head and neck. Their diagnostic, medical, and surgical skills include treatment of hearing loss and tinnitus, dizziness, infectious and inflammatory diseases of the ear, facial nerve disorders, congenital malformations of the ear, and tumors of the ear, hearing nerve, and skull base. As part of a team with neurosurgeons, they manage diseases and disorders of the cranial nerves and skull base.

Otosclerosis — Abnormal growth of bone around the ossicles and the inner ear. This bone prevents structures within the ear from working properly and causes hearing loss. For some people with otosclerosis, the hearing loss may become severe, but often the hearing can be improved by surgery or hearing aids.

Ototoxic Drugs — Drugs that can damage the hearing and balance organs located in the inner ear.

Otoscope — A magnifying and lighting tool utilized by healthcare workers to look into the ear canal.

Outer Ear — External portion of the ear, consisting of the pinna, or auricle, and the ear canal.

Otolaryngologist — An Ear, Nose, and Throat (ENT) physician.


Postlingually Deafened — Individual who becomes deaf after having acquired language.

Prelingually Deafened — Persons either born deaf or who lost his or her hearing early in childhood, before acquiring language.

Presbycusis — Loss of hearing that gradually occurs because of changes in the inner or middle ear in individuals as they grow older. The type of hearing loss often associated with presbycusis is a sensorineural hearing loss. Learn more about aging and hearing loss.

Profound Hearing Loss — A hearing loss ranging between 91 and 120 dB. This is essentially a total hearing loss.

Pure Tone Audiometry — Refers to the part of a complete hearing evaluation that includes the measuring of air-conduction and bone-conduction thresholds while using non-complex (pure) tones.

Real-Time Captioning — The process of producing either open or closed captions simultaneously with a live event. Real-time captioning incorporates a specialized computer system and stenographic keyboard much like those used in courtrooms.

Receiver — The name for the tiny speaker inside the hearing aid.

Residual Hearing — The amount of measurable, usable hearing left to a person with a hearing loss.

Reverse Oral Interpreter (Visible-to-Spoken) — A professional support specialist who is trained to read the lips of a person with impaired speech, and then voice the message for the benefit of hearing persons. This type of interpreter can be used in a hospital to read lips of patients who are able to move their lips, but are not able to produce sound, due to a tracheostomy or a laryngectomy.

Rubella — A viral infection characterized by fever and a skin rash resembling measles. If a pregnant woman contracts rubella, it may result in sensorineural hearing loss in the unborn child.

Screening (Hearing) — An evaluation of the auditory system that is generally not as in-depth as a traditional hearing test and often does not include the actual assessment of an individual’s thresholds, but instead results in “pass” or “fail.”

Sensorineural Hearing Loss — Hearing loss caused by damage to the sensory cells and/or nerve fibers of the inner ear. The most common type of hearing loss in adulthood. Learn more about sensorineural hearing loss.

Serous Otitis Media — Inflammation of the middle ear with an accumulation of thin, watery fluid.

Severe Hearing Loss — A hearing loss ranging between 71 and 90 dB.

Sign Language — Method of communication for people who are deaf in which hand movements, gestures, and facial expressions convey grammatical structure and meaning.

Sudden Hearing Loss — Loss of hearing that occurs quickly due to such causes as an explosion or a viral infection.

Speech Audiometry — The portion of an audiological evaluation that uses speech stimuli to measure the auditory system. Speech audiometry testing often includes the measurement of Speech Reception Thresholds (SRTs) utilizing two-syllable spondee words and the assessment of Word Recognition / Speech Discrimination scores utilizing single syllable words in a carrier phrase. Some speech audiometry tests use sentence materials instead of single word materials.

Speech–Language Pathologist — Healthcare professional who assesses speech and language development and treats language and speech disorders.

Swim Plugs — Material used to keep water out of the ear canal. They can be custom or non-custom made and help prevent infections resulting from water getting into the ear canal or middle ear cavity.

TDD — Telecommunications Device for the Deaf. See Text Telephone (TT).

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.

Telecommunications Relay Service — Sometimes called dual-party telephone relay service. Enables text telephone users to communicate with a non-text telephone user by way of a relay service communications assistant. The ADA mandated this nationwide relay service by 1993.

Text Telephone (TT) — Formerly TDD or TTY – a text telephone is a telecommunications device used by those who cannot understand on the phone. A typewriter-like unit shows the conversation on a screen so that it can be read. The transmission is with a special coding called Baudot or ASCII.

Tinnitus — Sensation of a ringing, roaring, or buzzing sound in the ears or head. It is often associated with hearing loss and noise exposure. Learn more about tinnitus.

T-Switch — A setting on a hearing aid that can be used with a hearing aid-compatible telephone, assistive listening device, and audio loop system. When the hearing aid is switched to “T”, it activates the induction telecoil (the technical name for the “T” switch), causing the hearing aid to pick up the magnetic field generated by the “hearing aid-compatible” telephone assistive device, or audio loop system being used.

TT or TTY — See Text Telephone.

Tympanoplasty — Surgical repair of the eardrum (tympanic membrane) or bones of the middle ear.

Tympanometry — A test, also referred to as immittance testing, done during an audiological evaluation that helps to assess the integrity of the tympanic membrane (eardrum) and the middle ear cavity. During tympanometry testing, a probe is inserted into and sealed in the ear canal and then a reflected tone is measured as the pressure in the ear canal is changed. The results are often grafted onto a tympanogram, showing the compliance at various positive and negative pressure levels.


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.

Vertigo — Illusion of movement; a sensation as if the external world were revolving around an individual (objective vertigo) or as if the individual were revolving in space (subjective vertigo).

Vestibular System — System in the body that is responsible for maintaining balance, posture, and the body’s orientation in space. This system also regulates locomotion and other movements and keeps objects in visual focus as the body moves.

Vestibule — Bony cavity of the inner ear.

Videotext Display — A real-time speech-to-text system. Audible words are typed and then projected onto a screen which can be read by the audience.

Visual Alarm Signal — A visual signal, usually a flashing light, which gives notice that an audible event has taken place.


White Noise — White noise is sound at certain frequencies that help mask other sounds. Using white noise is often helpful for people who suffer from tinnitus.

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.