Appendix A
Definitions and Technical Terms
This appendix consists of two glossaries. The first is a list of Social Security terms relevant to disability. The source is http://www.socialsecurity.gov/glossary.htm. The glossary is provided so that the reader can understand exactly how the Social Security Administration defines and uses each term.
The second glossary is a list of technical terms related to the science of hearing. The sources include glossaries from web sites maintained by the National Institute on Deafness and Other Communication Disorders, FreeHearingTest.com, and the Hope for Hearing Foundation. Some definitions have been adapted by the committee to specifically address terms as they are used in this report.
SOCIAL SECURITY TERMS
Term |
Explanation |
Appeal (Appeal Rights) |
Whenever Social Security makes a decision that affects your eligibility for Social Security or Supplemental Security Income (SSI) benefits, we send you a letter explaining our decision. If you disagree with our decision, you have the right to appeal it (ask us to review your case). If our decision was wrong, we’ll change it. |
Application for Benefits |
To receive Social Security or Black Lung benefits, Supplemental Security Income payments, or Medicare, you must complete and sign an application. You can apply for retirement benefits and spouse’s benefits online at http://www.socialsecurity.gov/ applytoretire, in person, or by telephone at 1-800-772-1213. Our TTY number is 1-800-325-0778. Many other services now are available through the Internet at http://www.socialsecurity.gov/ For more information see How To on our home page or go to http://www.ssa.gov/howto.htm. |
Base Years |
A worker’s (wage earner) base years for computing Social Security benefits are the years after 1950 up to the year of entitlement to retirement or disability insurance benefits. For a survivor’s claim, the base years include the year of the worker’s death. |
Benefits |
Social Security provides five major categories of benefits:
The retirement, family (dependents), survivor, and disability programs provide monthly cash benefits and Medicare provides medical coverage. |
Child |
We use the term “child” to include your biological child or any other child who can inherit your personal property under state law or who meets certain specific requirements under the Social Security Act; such as:
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Credits (Social Security Credits) |
Previously called “Quarters of Coverage.” As you work and pay taxes, you earn credits that count toward your eligibility for future Social Security benefits. You can earn a maximum of four credits each year. Most people need 40 credits to qualify for benefits. Younger people need fewer credits to qualify for disability or survivors’ benefits. For more information see How You Earn Credits (0510072). |
Decision Notice (Award Letter or Denial Letter) |
When you file for Social Security, we decide if you will receive benefits. We send you an official letter explaining our decision and, if benefits are payable, we tell you the amount you will get each month. |
Disability Benefits |
You can get disability benefits if you:
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Earnings Record (Lifetime Record of Earnings) |
A chronological history of the amount you earn each year during your working life time. The credits you earned remain on your Social Security record even when you change jobs or have no earnings. |
Evidence (Proofs) |
“Proofs.” The documents you must submit to support a factor of entitlement or payment amount. The people in your Social Security office can explain what evidence is required to establish entitlement and help you to get it. For more information see our How To page. |
Family Benefits (Dependent Benefits) |
When you’re eligible for retirement or disability benefits, the following people may receive benefits on your record:
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Health Insurance (Medicare) |
The federal health insurance program is for:
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Insured Status |
If you earned enough Social Security credits to meet the eligibility requirement for retirement or disability benefits or enable your dependents to establish eligibility for benefits due to your retirement, disability, or death, you have insured status. For more information see How You Earn Credits (05-10072). |
Medicaid |
A joint federal and state program that helps with medical costs for people with low incomes and limited resources. Medicaid programs vary from state to state, but most health care costs are covered if you qualify for both Medicare and Medicaid. For more information see the Official U.S. Government Site for Medicare and Medicaid Information. |
Medical Listings (Listing of Impairments) |
The Listing of Impairments describes, for each major body system, impairments that are considered severe enough to prevent a person from doing any gainful activity (or in the case of children under age 18 applying for SSI, cause marked and severe functional limitations). Most of the listed impairments are permanent or expected to result in death, or a specific statement of duration is made. For all others, the evidence must show that the impairment has lasted or is expected to last for a continuous period of at least 12 months. The criteria in the Listing of Impairments are applicable to evaluation of claims for disability benefits or payments under both the Social Security Disability Insurance and SSI programs. |
Medicare |
A nationwide, federally administered health insurance program that covers the cost of hospitalization, medical care, and some related services for most people over age 65, people receiving Social Security Disability Insurance benefits for 2 years, and people with end-stage renal disease. Medicare consists of two separate but coordinated programs—Part A (Hospital Insurance) and Part B (Supplementary Medical Insurance). See Health Insurance. For more information see Medicare and the Official U.S. Government Site for Medicare Information. |
OASDI (Old Age Survivors and Disability Insurance) |
The Social Security programs that provide monthly cash benefits to you and your dependents when you retire, to your surviving dependents, and to disabled worker beneficiaries and their dependents. |
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For more information see Evidence or Evidence Required to Establish Right to Benefits. |
QC (Quarter of Coverage) |
Social Security “credits.” As you work and pay taxes, you earn credits that count toward eligibility for future Social Security benefits. You can earn a maximum of four credits each year. Most people need 40 credits to qualify for benefits. Younger people need fewer credits to qualify for disability or for their spouse or children to qualify for survivors’ benefits. During their working lifetime most workers earn more credits than needed to be eligible for Social Security. These extra credits do not increase eventual Social Security benefits. However, the income earned may increase the benefit amount. For more information see How You Earn Credits (05-10072) and Credits, Social Security. |
Social Security |
Social Security is based on a simple concept: While you work, you pay taxes into the Social Security system, and when you retire or become disabled, you, your spouse, and your dependent children receive monthly benefits that are based on your reported earnings. Also, your survivors can collect benefits if you die. For more information see A Snapshot (05-10006). |
Spouse |
You are the spouse of the worker if, when he or she applied for benefits:
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Supplemental Security Income (SSI) |
A federal supplemental income program funded by general tax revenues (not Social Security taxes). It helps aged, blind, and disabled people who have little or no income |
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by providing monthly cash payments to meet basic needs for food, clothing, and shelter. |
Wage Earner |
A person who earns Social Security credits while working for wages or self-employment income. Sometimes referred to as the “Number Holder” or “Worker.” |
Widow |
You are the widow/widower of the insured person if, at the time the insured person died:
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The minimum age for
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GLOSSARY OF TECHNICAL TERMS RELATED TO HEARING
Term
Explanation
Acoustic Immittance
A series of tests, including tympanometry and acoustic reflex measures, that assess the transfer of acoustic energy through the middle ear system. These measures provide information about the integrity of the middle ear system and the structures comprising the acoustic reflex pathway.
Acoustic Nerve
The eighth cranial nerve, the nerve concerned with hearing and balance; also called the Vestibulocochlear Nerve.
Acoustic Neurinoma or Neuroma
Tumor, usually benign, which may develop on the hearing and balance nerves and can cause gradual hearing loss, tinnitus, and/or dizziness (sometimes called vestibular schwannoma). Also see Neurofibromatosis Type 2.
Acoustic Trauma
The term for damage to hearing due to a single exposure to extremely loud noise. (cf.See Noise-Induced Hearing Loss).
Acquired Deafness
Loss of hearing that occurs or develops some time during the lifespan but is not present at birth.
Air Conduction
The term for the transmission of sound through the outer ear, the bones of the middle ear, and into the inner ear.
Air-Bone Gap
The difference between the pure-tone thresholds assessed by air conduction (reflects the sensitivity of the entire peripheral auditory system) and bone conduction (reflects the sensitivity of the sensorineural system only).
Alerting Device
See Visual Alarm Signal.
Alport Syndrome
Hereditary condition characterized by kidney disease, sensorineural hearing loss, and sometimes eye defects.
American Sign Language (ASL)
Manual language with its own syntax and grammar, used in the United States primarily by people who are deaf.
Americans with Disabilities Act
The Americans with Disabilities Act (ADA), passed in 1990, which defines certain rights and requires certain accommodations for people with disabilities. The ADA definitions of a person with a disability are “(1) An individual with a physical or mental impairment that substantially limits one or more major life activities; (2) An individual with a record of a substantially limiting impairment; (3) An individual who is perceived to have such an impairment.”
Amplified Phone
Phone equipped with volume control in the handset. Public coin-operated phones have a volume control button on the wall unit.
Amplitude (Sound)
The magnitude of a sound wave, associated with the loudness of a perceived sound.
Assistive Listening Device (ALD)
A variety of electronic devices to assist hard-of-hearing people, with or without a hearing aid. Includes group and personal FM amplification systems, inductive loop amplification systems, infrared amplification systems, telephone amplifiers, etc.
Audio Loop (Induction Loop)
System that 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
The diagrammatic representation of hearing as the result of an audiological examination. An audiogram shows pure-tone thresholds by air and bone conduction for each ear. It is usually part of a report including results of other tests, such as immitance testing and speech recognition testing.
Audiologist
A health care professional who is trained to evaluate hearing loss and related disorders, including balance (vestibular) disorders and tinnitus, and to rehabilitate individuals with hearing loss and related disorders. An audiologist uses a variety of tests and procedures to assess hearing and balance function and to fit and dispense hearing aids and other assistive devices for hearing.
Audiometry
The measurement of hearing function.
Auditory Brainstem Response (ABR) Test
A test for hearing in infants, young children, and others who cannot cooperate for behavioral testing, and for ear and brainstem function in all patients. ABR involves attaching electrodes to the head to record electrical activity from the hearing nerve and other parts of the brain.
Auditory Evoked Potentials
Electrical potential (voltage) changes usually measured on the scalp that occur when sound stimuli activate the sensory cells of the auditory system and then the hearing centers of the brain. Some of these potentials can be used to diagnose hearing loss.
Auditory Nerve
Former name for the eighth cranial nerve, now called the Vestibulocochlear Nerve, that connects the inner ear to the brainstem and is responsible for hearing and balance.
Auditory Neuropathy
A condition involving hearing loss, often unstable, thought to be associated with damage to the eighth cranial nerve.
Auditory Perception
Ability to identify, interpret, and attach meaning to sound.
Auditory Prosthesis
Device that aids or enhances the ability to hear.
Auditory SteadyState Response
The auditory steady-state response (ASSR), previously known as the steady-state evoked potential (SSEP), is a way of objectively assessing frequency-specific responses. ASSR uses pure-tone (carrier) stimuli that are amplitude modulated with another tone at an appropriate modulation frequency. When the neural activity shows a preference for the modulation frequency over other frequencies in the analysis, it is assumed that the auditory system is responding to the carrier frequency.
Aural Rehabilitation
Techniques used with people who have hearing loss to improve their ability to receive spoken communication.
Auricle
Outer flap of the ear. Also called the Pinna.
Autoimmune Deafness
Condition in which an individual’s immune system produces abnormal antibodies or cellular responses that attack the body’s healthy tissues and cause hearing loss.
Azimuth
Direction from the listener in the horizontal plane; expressed as angular degrees on a circle whereby 0° is directly in front of the listener, and 180° is directly behind him or her.
Basilar Membrane
Thin sheet of tissue in the scala media that vibrates in response to movements in the liquid that fills the cochlea.
Bone Conduction
The term for the transmission of sound perceived through bones of the skull and lower jaw.
Bony Labyrinth
The cavity in the skull that encloses the Membranous Labyrinth.
Brainstem Implant
Auditory prosthesis that bypasses the cochlea and auditory nerve. This type of implant helps individuals who cannot benefit from a cochlear implant because the auditory nerves are not working.
Brainstem Testing
Test that measures hearing sensitivity without requiring responses from very young patients or persons who are unable to cooperate with behavioral tests. See Auditory Brainstem Response.
Captioning
Text display of spoken words, presented on a television or a movie screen, that allows a deaf or hard-of-hearing viewer to follow the dialogue and the action of a program simultaneously.
Central Auditory Processing Disorder
Inability to differentiate, recognize, or understand sounds due to abnormal brain function despite normal inner ear and eighth nerve function.
Cerumen
See Ear Wax.
Cholesteatoma
Accumulation of dead skin cells in the middle ear, caused by repeated middle ear infections or negative pressure in the middle ear. May be congenital.
Closed Captions (CC)
Text display of spoken dialogue and sounds on TV and videos, visible only to those using a caption decoder or TV built-in decoder chip.
Closed-Set Speech Recognition
Speech recognition test in which the possible stimulus items (words, syllables, etc.) are limited to a set of items known to the listener, e.g., when a list of several possible words is given and the listener indicates which he or she heard.
Cochlea
Snail-shaped structure in the inner ear that contains the organ of hearing.
Cochlear Implant
A surgically implanted electronic device that bypasses damaged structures in the inner ear and directly stimulates the auditory nerve, allowing some deaf individuals to learn to hear and interpret sounds and speech.
Conductive Hearing Loss
Hearing loss caused by a problem of the outer or middle ear, resulting in the inability of sound to be conducted to the inner ear.
Congenital Hearing Loss
Hearing loss that is present from birth and may or may not be hereditary.
Cued Speech
Method of communication that combines the mouth movements of speech with visual cues (hand shapes distinguish consonants, hand locations near the mouth distinguish vowels) to help deaf or hard-of-hearing individuals differentiate words that look similar on the lips (e.g., bunch vs. punch) or are hidden from view (e.g., gag).
Cycles Per Second
Measurement of frequency, or a sound’s pitch. See Hertz.
Cytomegalovirus (Congenital)
One group of herpes viruses that infects humans and can cause a variety of clinical symptoms, including deafness or hearing impairment; infection with the virus may be either before or after birth, but only prenatal infection causes hearing loss.
Deaf
A term (with a capital D) used by some people who have little or no useful residual hearing to identify themselves as members of Deaf Culture. Most Deaf people use sign language to communicate.
deaf
A term (with a lower-case d) used in this report to describe people who have little or
no useful residual hearing (i.e., severe or profound hearing loss), whether or not they identify themselves as Deaf.
Decibel (dB)
Unit used to express the intensity of a sound wave in logarithmic ratios to the base of 10. A 20-dB change is equivalent to a 100-fold change in acoustic intensity (energy flow per unit time per unit area) or a 10-fold change in sound pressure level.
Ear Canal
The short tube that conducts sound from the outer ear to the eardrum.
Ear Infection
Tissue-invasive growth of microorganisms, usually bacteria, viruses, or fungi, in the ear.
Ear Wax
Yellow secretion (Cerumen) from glands in the outer ear that keeps the skin of the ear dry and protected from infection.
Eardrum
The Tympanic Membrane, separating outer ear from middle ear. Vibrations of the air (sound) are transmitted by the eardrum to the bones of the middle ear.
Effusion
Fluid in the middle ear behind an intact tympanic membrane, usually seen in association with infection of the middle ear (Otitis Media).
Endolymph
Extracellular fluid inside the membranous labyrinth, including the balance organs (three semicircular canals, utricle, and saccule) and the cochlear duct or scala media of the cochlea. Endolymph is relatively high in potassium and low in sodium.
Eustachian Tube
Tube running from the nasal cavity to the middle ear, which opens during yawning and swallowing to allow air to flow to the middle ear. Helps keep middle ear pressure equal to ambient air pressure.
Exaggeration
A term used by the medical community to describe a patient’s claim of impairment or distress that is out of proportion to the medical findings that can be objectively documented. The term is preferred to “malingering” or other words that imply intent to deceive on the part of the patient.
Floor Effect
A floor effect occurs in a study when the tests used are so difficult that both experimental and control (for example, normally hearing and hard-of-hearing) groups score very poorly on them, obscuring any difference between the groups that might be attributed to the effect of independent variables.
Frequency
The number of vibrations per second (usually expressed in Hertz) of a sound.
Hair Cells
Sensory cells of the inner ear, which are topped with hair-like structures, the stereocilia, and which aid in the transduction of the mechanical energy of sound waves into nerve impulses.
Haptic Sense
Sense of physical contact or touch.
Hard-of-Hearing
Describes people with any degree of hearing loss ranging from mild to profound. They can understand some speech sounds, with or without a hearing aid. Most people who identify themselves as hard-of-hearing use oral speech, although a small number learn sign language. Generally, they are committed to participating in society by using their residual hearing plus hearing aids, speechreading, and assistive technology to aid communication.
Hearing
Sensory function in which sound waves in the air are converted to bioelectric signals, which are sent as nerve impulses to the brain, where they are interpreted.
Hearing Aid
Electronic device that brings amplified sound to the ear. A hearing aid usually consists of a microphone, an amplifier, and a receiver.
Hearing Disorder
Disruption in the normal hearing process that may occur in the outer, middle, or inner ear, whereby sound waves are not converted to electrical signals and nerve impulses are not transmitted to the brain to be interpreted.
Hearing Impaired
Generic term sometimes used to describe all persons with hearing loss. The term “people with hearing loss” is preferred.
Hereditary (or Genetic) Hearing Loss
Hearing loss passed down through generations of a family.
Hertz (Hz)
The unit used to express the frequency of a sound in cycles per second. One cycle per second equals 1 Hz.
Immitance Audiometry
Measurement of the function of the middle ear, used to diagnose conductive hearing loss.
Incus
One of three bones of the middle ear that help transmit sound waves from the outer ear to the cochlea.
Inner Ear
Part of the ear that contains both the organ of hearing (the cochlea, containing the organ of Corti) and the organ of balance (the labyrinth, containing the cristae and the maculae).
Interpreter, Sign Language
An interpreter who translates from voice to sign or from sign to voice (or both) in situations in which some people use spoken language and others sign.
Kilohertz (kHz)
Unit of frequency equal to 1000 Hz, or 1000 cycles per second.
Labyrinth
See Bony Labyrinth and Membranous Labyrinth.
Lesion
Any damage to an anatomical structure.
Lexical
Pertaining to words and their characteristics.
Malleus
One of three bones of the middle ear that help transmit sound waves from the outer ear to the cochlea.
Mastoid
The bone behind the ear canal, usually hollowed out by multiple air cells that communicate with the middle ear; part of the larger temporal bone.
Membranous Labyrinth
An interconnecting system of fluid-filled tubes inside the Bony Labyrinth that encloses the inner ear’s organs of hearing and balance.
Ménière’s Disease
Inner ear disorder that can affect both hearing and balance. It can cause episodes of vertigo, hearing loss, 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 or deafness.
Middle Ear
The part of the ear that includes the eardrum and three tiny bones of the middle ear, ending at the oval and round windows that lead to the inner ear, and connected to the nasal cavity by the Eustachian tube.
Neural Prostheses
Devices, such as the cochlear implant, that substitute for an injured or diseased part of the nervous system.
Neurofibromatosis Type 1 (NF-1, von Recklinghausen’s)
Group of inherited disorders in which non-cancerous tumors grow on several nerves that may include the hearing nerve. The symptoms of NF-1 include coffee-colored spots on the skin, enlargement and deformation of bones, and neurofibromas.
Neurofibromatosis Type 2 (NF-2)
Group of inherited disorders in which non-cancerous tumors grow on several nerves that usually include the hearing nerve. The symptoms of NF-2 include tumors on the hearing nerve that can affect hearing and balance. NF-2 may occur in the teenage years with hearing loss. Also see Acoustic Neurinoma.
Noise-Induced Hearing Loss
Hearing loss caused by exposure to loud sounds, usually over an extended period of time, that damage the sensitive structures of the inner ear. See Acoustic Trauma.
Nonsyndromic Hereditary Hearing Impairment
Hearing loss or deafness that is inherited and is not associated with other inherited clinical characteristics .
Open-Set Speech Recognition
Understanding speech when the set of possible stimulus items (words, syllables, etc.) is not known or limited.
Organ of Corti
The organ, located in the cochlea, which contains the hair cells that transduce sound waves into neural impulses that travel through the auditory nerve to the brain.
Ossicles
Collective name for the three bones of the middle ear.
Otitis Media
The term describing an inflammation or infection of the middle ear.
Otoacoustic Emissions (OAEs)
Low-intensity sounds produced by the inner ear that can be quickly measured with a sensitive microphone placed in the ear canal. Otoacoustic emissions testing can be used as one of a battery of physiological tests to diagnose hearing disorders.
Otolaryngologist
Physician or surgeon who specializes in diseases of the ears, nose, throat, and head and neck.
Otologist
Physician or surgeon who specializes in diseases of the ear.
Otosclerosis
A disease affecting the middle ear in which the stapes is fixed to the oval window so that it cannot move easily, leading to a conductive hearing loss that can be corrected by surgery or a hearing aid. Sometimes the inner ear is also affected, with a resultant mixed hearing loss (conductive plus sensorineural).
Ototoxic Drugs
Drugs such as aminoglycoside antibiotics and others that can damage the hearing and balance organs located in the inner ear in some individuals.
Outer Ear
The external portion of the ear that collects sound waves and directs them into the ear. Consists of the pinna (auricle) and the ear canal and is separated from the middle ear by the ear drum.
Oval Window
Opening in the bony wall of the cochlea to which is attached the footplate of the stapes bone; stapes vibration transmits sound into the cochlea.
Perception (Hearing)
See Auditory Perception.
Perilymph
Extracellular fluid between the bony and membranous labyrinths, filling the outer tubes (scala tympani and scala vestibuli) of the cochlea; also surrounds the semicircular canals, utricle, and saccule. Perilymph is relatively high in sodium and low in potassium.
Phoneme
The smallest unit of speech sound that serves to distinguish one utterance from another in a language.
Pinna
The outer, visible part of the ear, also called the Auricle.
Postlingually Deafened
Term for an individual who becomes deaf after having acquired language (defined as after age 2 years in this report).
Prelingually Deafened
Term for an individual who is born deaf or who loses his or her hearing early in childhood, before acquiring language (defined as before age 2 years in this report).
Presbycusis
The term describing hearing loss produced by degenerative changes of aging. Because there are so many causes of hearing loss, this label is tenable only when no other specific cause for older adult hearing loss can be found on careful otological evaluation.
Relay Service
Sometimes called dual-party telephone relay service. Enables text telephone users to communicate with a voice telephone user by use of a communications assistant who voices what the TTY user types to the voice phone user and types what the voice phone user says to the TTY user. The ADA mandated a nationwide relay service by 1993. Also see Text Telephone.
Retrocochlear
Term describing a structure or lesion beyond the cochlea in the auditory pathway from ear to brain.
Root-Mean-Square
The root mean square (or RMS) is a statistical or RMS measure of the magnitude of a varying quantity. It can be calculated for a series of discrete values or for a continuously varying function. The name comes from the fact that it is the square root of the mean of the squares of the values.
Round Window
One of two membranes separating the middle ear and the inner ear.
Semantic
Pertaining to the meaning of words or other units of speech.
Sensorineural Hearing Loss
Hearing loss caused by damage to the sensory cells or nerve fibers (or both) of the inner ear.
Sign Language
Method of communication for people who are deaf or hard of hearing in which hand movements, gestures, and facial expressions convey grammatical structure and meaning.
Also see American Sign Language.
Signal-to-Noise Ratio
A term that refers to the relative decibel levels of a signal and a noise. A signal-to-noise ratio of +10 dB means that the level of the signal is 10 dB higher than that of the noise, and a signal-to-noise ratio of –10 dB means that the level of the signal is 10 dB lower that that of the noise.
Sound Wave
Alternating low- and high-pressure areas moving through the air, which are interpreted as sound when collected in the ear.
Spectrum (Sound Spectrum)
The array of frequencies into which a complex sound can be analyzed. A sound spectrogram shows the relative intensities of the various frequencies as a function of time.
Speech Processor
Part of a cochlear implant that converts speech sounds into electrical impulses to stimulate the auditory nerve, allowing an individual to understand sound and speech.
Spondee
A two-syllable word with equal emphasis on both syllables; usually each syllable is a word in its own right (e.g., baseball, cowboy, railroad).
Stapes
One of three bones of the middle ear that help transmit sound waves from the outer ear to the cochlea.
Sudden Hearing Loss/Sudden Deafness
Loss of hearing that occurs quickly due to such causes as exposure to very intense noise, a viral infection, a rupture of one of the membranes connecting the middle ear to the inner ear, or the use of some drugs.
Syndromic Hearing Impairment
Hearing loss or deafness that, along with other characteristics, is inherited or passed down through generations of a family.
Syntactic
Pertaining to the grammatical features of speech, that is, how words and other semantic units are combined and arranged to communicate meaning.
Tactile Devices
Mechanical instruments that make use of touch to help individuals who have certain disabilities, such as deaf-blindness, to communicate.
Tectorial Membrane
Thin strip of membrane in the organ of Corti. It is in contact with sensory hairs, which are moved by sound vibrations, producing nerve impulses.
Text Telephone
Formerly TDD or TTY; a text telephone is a telecommunications device used by those who cannot understand speech on the phone. A typewriter-like unit shows the conversation on a screen so that it can be read. A text telephone must “talk” with another text telephone or a computer. Also see Relay Service.
Tinnitus
Sensation of a ringing, roaring, or buzzing sound in the ears or head that exists when no external sound stimulus is present. It is often associated with many forms of hearing impairment and noise exposure.
Tonotopic
Constructed so that specific frequencies are associated with corresponding neural places; the cochlea has a tonotopic organization.
Transducer
Any device that changes an input of one form of energy into an output of another, such as a microphone that changes the mechanical energy of sound waves into electrical energy.
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.
TTY
See Text Telephone.
Tympanic Membrane or Tympanum
Membrane separating the outer ear from the middle ear; the ear drum.
Usher Syndrome
Hereditary disease that affects hearing and vision and sometimes balance.
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 head moves.
Vestibule
The part of the bony labyrinth that houses the utricle and saccule.
Vestibulocochlear Nerve
The eighth cranial nerve, formerly called the auditory nerve, that connects the inner ear to the brainstem and is responsible for hearing and balance.
Vibrotactile Aids
Mechanical instruments that help individuals who are deaf to detect and interpret sound through the sense of touch.
Visual Alarm Signal
A visual signal (flashing light) alerting a person about a sound, such as a doorbell, fire alarm, ringing telephone. Some systems monitor a single event; others can monitor several events and indicate which event has occurred.
Waardenburg Syndrome
Hereditary disorder that is characterized by hearing impairment, a white shock of hair and/or distinctive blue color to one or both eyes, and wide-set inner corners of the eyes. Balance problems are also associated with some types of Waardenburg syndrome.
Wavelength
Distance between the peaks of successive sound waves.
White Noise
A complex sound made up of sounds of all frequencies, used to mask other sounds.