acoustic neuroma (Also called vestibular schwannoma.) - a tumor, usually benign, which develops on the hearing and balance nerves and can cause gradual hearing loss, tinnitus, and dizziness.
acquired deafness - loss of hearing that occurs or develops over the course of a lifetime; deafness not present at birth.
ageusia - loss of the sense of taste.
Alport's syndrome - a hereditary condition characterized by kidney disease, sensorineural hearing loss, and some difficulties with eye defects.
American Sign Language (ASL) - manual (hand) language with its own syntax and grammar used primarily by people who are deaf.
anosmia - absence of the sense of smell.
aphasia - total or partial loss of ability to use or understand language; usually caused by stroke, brain disease, or injury.
aphonia - complete loss of voice.
apraxia - inability to make a voluntary movement in spite of being able to demonstrate normal muscle function.
articulation disorder - inability to correctly produce speech sounds (phonemes) because of imprecise placement, timing, pressure, speed, or flow of movement of the lips, tongue, or throat.
assistive devices - technical tools and devices such as alphabet boards, text telephones, or text-to-speech conversion software used to assist people with physical or emotional disorders in performing certain actions, tasks, and activities.
audiologist - a healthcare professional trained to identify and measure hearing impairments and related disorders using a variety of tests and procedures.
auditory brainstem response (ABR) test - test used for hearing in infants and young children, or to test for brain functioning in unresponsive patients.
auditory nerve - eighth cranial nerve that connects the inner ear to the brainstem.
auditory perception - ability to identify, interpret, and attach meaning to sound.
auditory prosthesis - device that substitutes or enhances the ability to hear.
augmentative devices - tools that help individuals with limited or absent speech to communicate.
aural rehabilitation - techniques used with people who are hearing impaired to improve ability to speak and to communicate.
autism - brain disorder that begins in early childhood and persists throughout adulthood; affects three crucial areas of development: communication, social interaction, and creative or imaginative play.
autoimmune deafness - hearing loss in an individual that may be associated with a tissue-causing disease, such as rheumatoid arthritis or lupus.
balance - biological system that enables individuals to know where their bodies are in the environment and to maintain a desired position; normal balance depends on information from the labyrinth in the inner ear, and from other senses such as sight and touch, as well as from muscle movement.
balance disorder - disruption in the labyrinth, the inner ear organ that controls the balance system allowing individuals to know where their bodies are in the environment.
barotrauma - injury to the middle ear caused by a reduction of air pressure.
benign paroxysmal positional vertigo (BPPV) - balance disorder that results in a sudden onset of dizziness, spinning, or vertigo that occurs when suddenly moving the head from one position to another.
brainstem implant - auditory prosthesis that bypasses the cochlea and auditory nerve to help individuals who cannot 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 a deaf or hard-of-hearing viewer to follow the dialogue and the action of a program simultaneously.
central auditory processing disorder - inability of individuals with normal hearing and intelligence to differentiate, recognize, or understand sounds.
chemosensory disorders - disorders or diseases of smell or taste.
cholesteatoma - accumulation of dead cells in the middle ear caused by repeated middle ear infections.
cochlea - snail-shaped structure in the inner ear that contains the organ of hearing.
cochlear implant - medical device that bypasses damaged structures in the inner ear and directly stimulates auditory nerve to allow some deaf individuals to learn to hear and interpret sounds and speech.
computed tomography scan (Also called a CT or CAT scan.) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
conductive hearing impairment - hearing loss caused by dysfunction of the outer or middle ear.
cued speech - method of communication that combines speech reading with a system of handshapes placed near the mouth to help deaf or hard-of-hearing individuals differentiate words that look similar on the lips.
cytomegalovirus (congenital) - one group of herpes viruses that infect 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.
decibel - unit that measures the intensity or loudness of sound.
dizziness - physical unsteadiness, imbalance, and lightheadedness associated with balance disorders.
dysarthria - group of speech disorders caused by disturbances in the strength or coordination of the muscles of the speech mechanism as a result of damage to the brain or nerves.
dysequilibrium - any disturbance of balance.
dysfluency - disruption in the smooth flow or expression of speech.
dysgeusia - distortion or absence of the sense of taste.
dysosmia - distortion or absence of the sense of smell.
dysphagia - difficulty swallowing.
dysphonia - any impairment of the voice or difficulty speaking.
dyspraxia of speech - partial loss of the ability to consistently pronounce words in individuals with normal muscle tone and coordination of the speech muscles.
dystonia - abnormal muscle tone of one or more muscles.
ear infection - presence and growth of bacteria or viruses in the ear.
ear wax - yellow secretion from glands in the outer ear (cerumen) that keeps the skin of the ear dry and protected from infection.
endolymph - fluid in the labyrinth - the organ of balance located in the inner ear.
gustation - act or sensation of tasting.
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.
hearing - series of events in which sound waves in the air are converted to electrical signals that are sent as nerve impulses to the brain where they are interpreted.
hearing aid - electronic device that brings amplified sound to the ear.
hearing disorder - disruption in the normal hearing process; sound waves are not converted to electrical signals and nerve impulses are not transmitted to the brain to be interpreted.
hoarseness - abnormally rough or harsh-sounding voice caused by vocal abuse and other disorders.
hypogeusia - diminished sensitivity to taste.
hyposmia - diminished sensitivity to smell.
inner ear - part of the ear that contains both the organ of hearing (the cochlea) and the organ of balance (the labyrinth).
labyrinth - organ of balance located in the inner ear. The labyrinth consists of three semicircular canals and the vestibule.
labyrinthine hydrops - excessive fluid in the organ of balance (labyrinth) that can cause pressure or fullness in the ears, hearing loss, dizziness, and loss of balance.
labyrinthitis - viral or bacterial infection or inflammation of the inner ear that can cause dizziness, loss of balance, and temporary hearing loss.
Landau-Kleffner syndrome - A childhood disorder of unknown origin that can be identified by gradual or sudden loss of the ability to understand and use spoken language.
language - system for communicating ideas and feelings using sounds, gestures, signs, or marks.
language disorders - problems with verbal communication and the ability to use or understand the symbol system for interpersonal communication.
laryngeal neoplasms - abnormal growths in the larynx (voice box) that can be cancerous or noncancerous.
laryngeal nodules - noncancerous, callous-like growths on the inner parts of the vocal folds (vocal cords).
laryngeal paralysis - loss of function or feeling of one or both of the vocal folds.
laryngectomy - surgery to remove part or all of the larynx or voice box.
laryngitis - hoarse voice or the complete loss of the voice because of irritation to the vocal folds (vocal cords).
larynx - valve structure between the trachea (windpipe) and the pharynx (the upper throat) that is the primary organ of voice production.
magnetic resonance imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
mastoid - back portion of the temporal bone behind the ear.
mastoid surgery - surgical procedure to remove infection from the mastoid bone.
Meige syndrome - A movement disorder that can involve excessive eye blinking (blepharospasm) with involuntary movements of the jaw muscles, lips, and tongue (oromandibular dystonia).
Ménière's disease - an inner ear disorder that can affect both hearing and balance; can cause 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 - part of the ear that includes the eardrum and three tiny bones of the middle ear, ending at the round window that leads to the inner ear.
misarticulation - inaccurately produced speech sound (phoneme) or sounds.
motion sickness - dizziness, sweating, nausea, vomiting, and generalized discomfort experienced when an individual is in motion.
motor speech disorders - group of disorders caused by the inability to accurately produce speech sounds (phonemes).
neural plasticity - ability of the brain and/or certain parts of the nervous system to change in order to adapt to new conditions, such as an injury.
neural prostheses - devices that substitute for an injured or diseased part of the nervous system to enhance the function.
neural stimulation - to activate or energize a nerve through an external source.
neurofibromatosis - a group of inherited disorders in which noncancerous tumors grow on several nerves that may include the hearing nerve.
neurogenic communication disorder - inability to exchange information with others because of hearing, speech, and/or language problems caused by impairment of the nervous system.
noise-induced hearing loss - hearing loss that is caused either by a one-time or repeated exposure to very loud sound(s) or sounds at various loudness levels over an extended period of time.
nonsyndromic hereditary hearing impairment - hearing loss or deafness that is inherited and is not associated with other inherited clinical characteristics.
odorant - substance that stimulates the sense of smell.
olfaction - the act of smelling.
olfactometer - device for estimating the intensity of the sense of smell.
open-set speech recognition - understanding speech without visual clues.
otitis media - inflammation of the middle ear caused by infection.
otitis externa - inflammation of the outer part of the ear extending to the auditory canal.
otoacoustic emissions - low-intensity sounds produced by the inner ear that can be quickly measured with a sensitive microphone placed in the ear canal.
otolaryngologist - physician/surgeon who specializes in diseases of the ears, nose, throat, and head and neck.
otologist - physician/surgeon who specializes in diseases of the ear.
otosclerosis - abnormal growth of bone in the inner ear, which prevents structures within the ear from working properly, resulting in a gradual loss of hearing.
ototoxic drugs - drugs that can damage the hearing and balance organs located in the inner ear.
outer ear - external portion of the ear, consisting of the pinna, or auricle, and the ear canal.
parosmia - any disease or perversion of the sense of smell, especially the subjective perception of odors that do not exist.
perception (hearing) - process of knowing or being aware of information through the ear.
perilymph fistula - leakage of inner ear fluid to the middle ear that occurs without apparent cause or is associated with head trauma, physical exertion, or barotrauma.
phonology - study of speech sounds.
positron emission tomography (PET) scan - a computer-based imaging technique that uses radioactive substances to examine body processes. For example, a PET scan of the heart provides information about the flow of blood through the coronary arteries to the heart.
postlingually deafened - individual who becomes deaf after having learned language.
prelingually deafened - individual who is either born deaf or who lost hearing early in childhood, before learning language.
presbycusis - loss of hearing that gradually occurs because of changes in the inner or middle ear in individuals as they grow older.
round window - membrane separating the middle ear and inner ear.
sensorineural hearing loss - hearing loss caused by damage to the sensory cells and/or nerve fibers of the inner ear.
sign language - language of hand shapes, facial expressions, and movements used as a form of communication.
smell - to perceive odor or scent through stimuli affecting the olfactory nerves.
smell disorder - inability to perceive odors that may be temporary or permanent.
sound vocalization - ability to produce voice.
spasmodic dysphonia - momentary disruption of voice caused by involuntary movements of one or more muscles of the larynx or voice box.
specific language impairment (or SLI) - difficulty with the organized-symbol-system communication in the absence of problems such as mental retardation, hearing loss, or emotional disorders.
speech - making definite vocal sounds that form words to express thoughts and ideas.
speech disorder - defect or abnormality that prevents an individual from communicating by means of spoken words.
speech processor - part of a cochlear implant that converts speech sounds into electrical impulses to stimulate the auditory nerve.
speech-language pathologist - health professional trained to evaluate and treat people who have voice, speech, language, or swallowing disorders, including hearing impairment, that affect their ability to communicate.
stuttering - frequent repetition of words or parts of words that disrupts the smooth flow of speech.
sudden deafness - loss of hearing that occurs quickly from such causes as explosion, a viral infection, or the use of some drugs.
swallowing disorders - any of a group of problems that interfere with the transfer of food from the mouth to the stomach.
syndromic hearing impairment - hearing loss or deafness that is inherited or passed through generations of a family.
taste - sensation produced by a stimulus applied to the gustatory nerve endings in the tongue; the four tastes are salt, sour, sweet, and bitter; some say there is a fifth taste described as savory.
taste buds - groups of cells located on the tongue that enable one to recognize different tastes.
taste disorder - inability to perceive different flavors.
throat disorders - disorders or diseases of the larynx (voice box) or esophagus.
thyroplasty - surgical technique to improve voice by altering the cartilages of the larynx. Also known as laryngeal framework surgery.
tinnitus - sensation of a ringing, roaring, or buzzing sound in the ears or head; often associated with various forms of hearing impairment.
tongue - large muscle on the floor of the mouth that manipulates food for chewing and swallowing; the main organ of taste, and assists in forming speech sounds.
Tourette syndrome - neurological disorder characterized by recurring movements and sounds (called tics).
tracheostomy - surgical opening into the trachea (windpipe) to help someone breathe who has an obstruction or swelling in the larynx (voice box) or upper throat.
tympanoplasty - surgical repair of the eardrum (tympanic membrane) or bones of the middle ear.
Usher's syndrome - a hereditary disease that affects hearing and vision.
velocardiofacial syndrome - inherited disorder characterized by cleft palate, heart defects, characteristic facial appearance, minor learning problems, and speech and feeding problems.
vertigo - illusion of movement; sensation that the external world is revolving around an individual (objective vertigo) or that the individual is revolving in space (subjective vertigo).
vestibular neuronitis - infection at the vestibular nerve.
vestibular system - system in the body that is responsible for maintaining the body's orientation in space, balance, and posture; also regulates locomotion and other movements and keeps objects in visual focus as the body moves.
vestibule - bony cavity of the inner ear.
vibrotactile aids - mechanical instruments that help individuals who are deaf detect and interpret sound through the sense of touch.
vocal cords (vocal folds) - muscularized folds of mucous membrane that extend from the larynx (voice box) wall; enclosed in elastic vocal ligament and muscle that control the tension and rate of vibration of the cords as air passes through them.
vocal cord paralysis - inability of one or both vocal folds (vocal cords) to move because of damage to the brain or nerves.
vocal tremor - trembling or shaking of one or more of the muscles of the larynx resulting in an unsteady-sounding voice.
voice - sound produced by air passing out through the larynx and upper respiratory tract.
voice disorders - group of problems involving abnormal pitch, loudness, or quality of the sound produced by the larynx (voice box).
Waardenburg syndrome - hereditary deafness that is characterized by hearing impairment, a white shock of hair, and/or distinctive blue color to one or both eyes, as well as wide-set inner corners of the eyes; balance problems are also associated with some types of Waardenburg syndrome.