Glossary of Terms
Acoustic Neuroma – 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 sometime in the course of a lifetime, but is not present at birth.
American Sign Language (ASL) – Manual (sign) language with its own syntax and grammar used primarily by people who are deaf.
Assistive Devices – Tools and devices such as alarms, alerting devices, or FM systems used to help people hear to perform daily actions, tasks, and activities. Learn more about assistive listening devices.
Audiologist – A health care professional trained to evaluate hearing loss and related disorders, including balance (vestibular) disorders and tinnitus, and to rehabilitate people with hearing loss and related disorders. Audiologists use 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 loss. Most audiologists have advanced doctorate degrees.
Auditory Brainstem Response (ABR) Test – Used to test the hearing of infants and young children, or to test the functioning of the hearing nerve. This painless procedure involves attaching recording disks to the head to record electrical activity from the hearing nerve and brain stem.
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. Learn more about APD.
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-causing disease, such as rheumatoid arthritis or lupus.
Balance – A 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, from other senses such as sight and touch, and from muscle movement.
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.
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.
Cerumen (Ear Wax) – Yellow secretion from glands in the outer ear canal that keeps the skin of the ear canal dry and protected from infection.
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.
Cochlear Implant – Medical device that bypasses damaged structures in the inner ear and indirectly stimulates the auditory nerve, allowing some deaf and hard of hearing individuals to learn to hear and interpret sounds and speech. Learn more about cochlear implants.
Cognition – Thinking skills that include perception, memory, awareness, reasoning, judgment, intellect, and imagination.
Conductive Hearing Loss – Hearing loss caused by an abnormal transmission of sound in the outer or middle ear. Most common in children.
Decibel (dB) – The unit used to measure the intensity or loudness of sound.
Dizziness – Physical unsteadiness, imbalance, and lightheadedness associated with balance disorders. Learn more about balance disorders and dizziness.
Dysequilibrium – Any disturbance of balance.
Ear Infection – Presence and growth of bacteria or viruses usually in the middle ear.
Ear Wax (Cerumen) – Yellow secretion from glands in the outer ear canal that keeps the skin of the ear canal dry and protected from infection.
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 – A sense, series of events in which sound waves in the air are converted to electrical signals, which are sent as nerve impulses to the brain, where they are interpreted as sound.
Hearing Aid – A battery-powered electronic device that brings amplified sound to the ear. A hearing aid usually consists of a microphone, amplifier, and receiver. Learn more about hearing aids.
Hearing Loss – Disruption in the normal process that may occur in either the outer, middle, or inner ear, whereby sound waves are not conducted to the inner ear, converted to electrical signals and/or nerve impulses are not transmitted to the brain to be interpreted as sound. Learn more about hearing loss.
Hereditary Hearing Impairment – Inherited hearing loss that is passed down through the family.
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.
Labyrinthitis – Viral or bacterial infection or inflammation of the inner ear that can cause dizziness, loss of balance, and temporary hearing loss.
Mastoid – Hard, boney structure behind the ear.
Mastoid Surgery – Surgical procedure to remove infection from the mastoid bone.
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 or 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.
Motion Sickness – Dizziness, sweating, nausea, vomiting, and generalized discomfort experienced when an individual is in motion.
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 90-decibel level over an extended period of time that damage the sensitive structures of the inner ear. Learn more about noise-induced hearing loss.
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.
Otologist – Physician/surgeon who specializes in diseases of the ear.
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.
Outer Ear – External portion of the ear, consisting of the pinna, or auricle, and the ear canal.
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.
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.
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.
Tinnitus – Sensation of a ringing, roaring, or buzzing sound in the ears or head. It is often associated with many forms of hearing loss and noise exposure. Learn more about tinnitus.
Tympanoplasty – Surgical repair of the eardrum (tympanic membrane) or bones of the middle ear.
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 – Boney cavity of the inner ear.