Medical Dictionary: Hearing Loss

In addition to information new hearing aid technologies, find in-depth information on the causes, diagnosis, and treatment of hearing loss. This medical dictionary covers the terms used in the report, Hearing Loss: A guide to prevention and treatment, and includes details on the causes of hearing loss, how to prevent it, hearing aids, and how to live with it.

audiogram: A graph showing the shape, or nature, of your hearing loss as measured by a complete hearing evaluation.

audiologist: A health professional who assesses hearing and balance, as well as fits and dispenses hearing aids.

auditory nerve: The nerve in the inner ear that receives electrical signals from the hair cells and relays them to the brain. Also known as the eighth cranial nerve.

cochlea: A snail-shaped structure in the inner ear where sound is changed into nerve impulses that the brain can interpret as a particular sound.

cochlear implant: An electronic device that is implanted in the inner ear to restore some hearing to a deaf person.

conductive hearing loss: Hearing loss caused by a blockage in the middle ear that prevents sound waves from passing through to the inner ear.

decibel: A unit of measurement for the loudness of a sound, with the highest decibels indicating the loudest sounds.

ear canal: An inch-long passage leading from the outer ear to the eardrum.

eardrum: A drum-tight membrane between the ear canal and the middle ear. As it vibrates, it transfers sound waves to the bones in the middle ear.

earwax: A substance secreted by the sebaceous glands in the ear that helps clean the ear canal, keeps dirt out of the ear, and lubricates the skin in the ear.

frequency: The pitch of a sound measured by the speed at which sound waves vibrate.

gain: A hearing aid’s power, measured in the number of decibels that it can add to sound.

hair cells: Sensory cells in the inner ear.

hearing aid: An electronic device that amplifies sound in the ear, allowing a person to hear better.

hertz: The measurement of a sound’s frequency, expressed in cycles per second.

inner ear: The deepest part of the ear, consisting of the cochlea and the labyrinth.

labyrinth: The inner ear structure that contains the balance organs.

mastoid bone: The bone in the skull behind the ear.

Ménière’s disease: An illness caused by a fluid imbalance in the inner ear. Symptoms include dizziness, tinnitus, and periodic hearing loss.

middle ear: The space between the outer ear and the inner ear that contains the three ossicles, or bones, involved in hearing.

ossicles: The malleus, incus, and stapes — the three bones in the middle ear that move in response to sound vibrations.

otic capsule: The bone that surrounds the labyrinth of the inner ear.

otitis externa: A bacterial or fungal infection of the skin lining the ear canal of the outer ear. It’s most common during the summer and in hot, humid climates. Also called swimmer’s ear.

otitis media: An infection of the middle ear, which can be acute or chronic.

otosclerosis: Abnormal bony growth that keeps one of the three tiny bones in the middle ear from moving, thereby preventing sound waves from passing through the ear.

outer ear: The external part of the ear, or auricle, as well as the ear canal and the eardrum.

presbycusis: Age-related hearing loss, typically occurring in people over age 40.

Rinne test: A simple hearing test that uses a tuning fork to determine what type of hearing loss a person has.

sensorineural hearing loss: Permanent hearing loss caused by damage to the cochlea, hair cells, or auditory nerve.

TDD: Telecommunications device for the deaf. Machinery that allows a hearing-impaired person to send and receive typed messages over the telephone.

tinnitus: A ringing in the ears or some other sound that has no external cause.

tympanic membrane: The eardrum.

tympanometry: A diagnostic test involving a probe that sends sound waves to the eardrum to help determine if the person’s hearing loss is due to a problem in the middle ear. Also known as impedance testing.

vestibular system: The balance organs, located in the labyrinth in the inner ear.

Weber test: A hearing test that uses a tuning fork to diagnose one-sided hearing loss.