Glossary of Terms

Acoustic Nerve - the eighth cranial nerve, the nerve concerned with hearing and balance.

Amplitude - the height of a sound wave, as associated with the loudness of a sound.

Ampulla - the swelling at the base of each semicircular canal, containing sensory cells which detect movement of the fluid within the canals.

Anvil - one of three bones of the middle ear that help transmit sound waves from the outer ear to the cochlea. Also called the Incus.

Assistive Device - any device other than a hearing aid which helps the hearing impaired.

Audiogram - a graph depicting the ability to hear sounds at different frequencies.

Audiologist - a person trained in the science of hearing and hearing impairments, who can administer tests and help in the rehabilitation of hearing-impaired people.

Audiometry - the measurement of hearing acuity.

Auditory Nerve - the nerve carrying electrical signals from the inner ear to the base of the brain.

Auricle - outer flap of the ear. Also called the pinna.

Basilar Membrane - thin sheet of material which vibrates in response to movements in the liquid that fills the cochlea.

Bony Labyrinth - the cavity in the skull which contains the inner-ear mechanism.

Brainstem testing - measures hearing sensitivity without requiring responses from very young patients or persons who are unable to communicate.
Bone Conduction - the conduction of sound waves through reverberations of the mastoid bone to the inner ear.

CC (Closed Captioned) - a broadcast television program that includes a signal which produces descriptive subtitles on the screen. Requires CC converter.

Cerumen - ear wax.

Cochlea - shaped like a snail's shell, this organ of the inner ear contains the organ of Corti, from which eighth nerve fibers send hearing signlals to the brain.

Cochlear Implant - replacement of part or all of the function of the inner ear.

Conductive Hearing Loss - hearing loss caused by a problem of the outer or middle ear, resulting in the inablilty of sound to be conducted to the inner ear.

Congenital Hearing Loss - hearing loss that is present from birth which may or may not be hereditary.

Cortex - that surface of the brain where sensory information is processed.

Crista - sensory cells within the semicircular canals which detect fluid movement.

Cupola - jelly-like covering of the sensory hairs in the ampullae of the semicircular canals which responds to movement in the surrounding fluid and assists in maintaining balance.

Cycles (per second) - measurement of frequency, or a sound's pitch.

Decibel - measurement of the volume or loudness of a sound.

Ear Canal - the short tube which conducts sound from the outer ear to the eardrum.

Eardrum - membrane separating outer ear from middle ear: the tympanum.

Eustachian Tube - tube running from the nasal cavity to the middle ear. Helps maintain sinus and middle ear pressure, protecting the ear drum.

Frequency - the number of vibrations per second of a sound.

Hammer - one of three bones of the middle ear that help transmit sound waves from the outer ear to the cochlea. Also called the Malleus.

Impedance Audiometry - test for measuring the ability to hear sound waves transmitted through bone.

Incus - one of three bones of the middle ear that help transmit sound waves from the outer ear to the cochlea. Also called the anvil.

Inner Ear - the portion of the ear, beginning at the oval window, which transmits sound signals to the brain and helps maintain balance. Consists of the cochlea and vestibular apparatus.

Labyrinthitis - a viral infection in the vestibular canal which may cause vertigo.

Macula - within the organs of balance, area containing sensory cells which measure head position.

Malleus - one of three bones of the middle ear that help transmit sound waves from the outer ear to the cochlea. Also called the Hammer.

Mastoid - the bone in which the entire ear mechanism is housed. Part of the larger temporal bone.

Meniere's Disease - a condition resulting from fluid buildup in the inner ear, leading to episodes of hearing loss, tinnitus and vertigo.

Middle Ear - the portion of the ear between the eardrum and the oval window which transmits sound to the inner ear. Consists of the hammer, anvil and stirrup.

Nerve Loss Deafness - a term used to differentiate inner-ear problems from those of the middle ear.

Organ of Corti - the organ, located in the cochlea, which contains the hair cells that actually transmit sound waves from the ear through the auditory nerve to the brain.

Ossicles - collective name for the three bones of the middle ear: hammer, anvil and stirrup.

Otoliths - stone-like particles in the macula which aid in our awareness of gravity and movement.

Otosclerosis- a conductive hearing loss caused when the middle ear no longer transmits sound properly from the eardrum to the inner ear.

Otitis Media - infection of the middle ear.

Otology - branch of medicine concentrating on diseases of the ear.

Outer Ear - the external portion of the ear which 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 - membrane that vibrates, transmitting sound into the cochlea. Separates the middle ear from the inner ear.

Perilymph - watery liquid that fills the outer tubes running through the cochlea.

Pinna - the outer, visible part of the ear, also called the auricle.

Presbycusis - a hereditary sensory-neural hearing loss that comes with aging.

Saccule - inner ear area which contains some of the organs that measure position and gravity.

Semicircular Canals - curved tubes containing fluid, movement of which which makes us aware of turning sensations as the head moves.

Sensorineural Hearing Loss - Hearing loss resulting from an inner ear problem.

Sound Wave - alternating low and high pressure areas, moving through the air which are as interpreted as sound when collected in the ear.

Stapes - one of three bones of the middle ear that help transmit sound waves from the outer ear to the cochlea. Also called the Stirrup.

Stirrup - one of three bones of the middle ear that help transmit sound waves from the outer ear to the cochlea. Also called the Stapes.

Tectorial Membrane - thin strip of membrane in contact with sensory hairs which sound vibrations move producing nerve impulses. In the organ of Corti.

Tinnitus - ringing or buzzing in the ears.

TTY (phone device) - dialog is achieved at any distance as words, typed into a TTY, are converted to phone signals and appear, or are printed, as words on a receiving TTY machine.

Tympanum - membrane separating outer ear from middle ear: the eardrum.

Vertigo - the sensation of moving or spinning while actually sitting or lying still.

Vestibular Apparatus - part of the cochlea concerned with maintaining balance.

Wave Length - distance between the peaks of successive sound waves.

White Noise - a sound, such as running water, which masks all speech sounds.