Tympanic
Referring to the eardrum or the cavity of the middle ear.
Tympanic Membrane
The eardrum. It separates the outer ear from the middle ear and is conducts sound to the middle ear. More technically, the eardrum is a thin, taut, concave, pearly-white membrane that covers the entrance to the middle ear. It vibrates in response to incoming sounds, which are then transmitted to the middle and inner ear.
Tympanogram
A measure of the mobility of the eardrum. A tympanogram is a graph that shows how well the middle ear pressure regulating system is working, whether the eardrum is intact and how well it moves. It can be used to identify middle ear disorders that require medical attention.
Tympanometer
Instrument used to screen for middle-ear disorders such as otitis media.
Tympanometry
A test, using a tympanometer, that checks the function of the eardrum and middle ear by measuring whether the eardrum moves normally when varying amounts of air pressure are applied to the ear.
Tympanoplasty
Surgery to repair or replace a damaged eardrum.
Tympanostomy Tube
Tympanum
The middle ear cavity.
UCL
Uncomfortable Loudness Level (UCL)
The volume at which sounds become uncomfortably loud. Any further increase in volume would hurt.
Unilateral Hearing Loss
Hearing loss in one ear only. Unilateral hearing loss adversely affects the educational process in a significant percentage of students who have it, even though they have normal hearing in their other ear.
Utricle
A chamber in the vestibular labyrinth that helps monitor the position of your head in relation to the ground. The utricle is responsible for detection of horizontal movement.
VCO
See Voice Carry Over.
Vent
A small hole through an In-the Ear hearing aid or ear mold to allow air into the ear. The size of the vent can be modified to change the acoustical properties of a hearing aid.
Ventilation Tube
A small tube inserted into the eardrum that relieves the pressure of a middle ear infection by allowing fluid to drain from the middle ear. (Also called a Pressure Equalization Tube.)
Vertigo
Vertigo is the illusion or sensation of movement when none is present. If may feel like you are spinning around, or that the room is spinning around you. Frequently vertigo is accompanied by feelings of imbalance and/or nausea. Vertigo is a common result of damage to the balance system of the inner ear. Less often, it is caused by abnormal conditions in the central nervous system. Many ototoxic drugs can cause vertigo.
Vestibular Aqueduct
A narrow bony canal (aqueduct) that runs through the skull, connecting the inner ear (vestibule) to the cranial cavity—hence its name. Running through this bony canal is a membranous tube called the endolymphatic duct which connects the endolymphatic sac (located between the skull and the brain) and the inner ear. It is filled with endolymphatic fluid (endolymph).
Vestibular Labyrinth
A structure of the inner ear made up of three fluid-filled, semicircular tubes (canals), the utricle and the saccule that assist with balance. (See also Vestibular System.)
Vestibular Nerve Section
Surgery to cut the vestibular branch of the 8th cranial nerve. This is done when intractable vertigo resulting from a condition such as Meniere’s disease becomes debilitating. When this is done, the person has no balance function in that ear, but no more vertigo either.
Vestibular Rehabilitation
A therapeutic program that uses exercises to help you regain your sense of balance.
Vestibular System
That portion of the inner ear and the central nervous system involved with the sense of balance. It includes the semi-circular canals, saccule, utricle and vestibule. This system controls your equilibrium (balance) and stabilizes your eyes in space. It works together with your brain to sense, maintain and regain your balance and a sense of where your body and its part are positioned. It regulates movement (walking, running, etc.) and keep objects in visual focus as the body moves. Many ototoxic drugs can damage your vestibular system. This can give rise to a whole host of balance-related problems.
Vestibulocochlear Nerve
See Eighth Cranial Nerve.
Video Relay Service (VRS)
A form of Telecommunications Relay Service which allows a user with a videophone to connect with a TRS Communications Assistant (CA) who uses American Sign Language (ASL) to facilitate telephone calls between people who use ASL (typically deaf people) and others.
Visual Reinforcement Audiometry (VRA)
A hearing testing procedure for children in which the child’s responses to sound are reinforced with a visual event (such as a toy that moves). The audiologist attempts to condition the child to look for the toy when a sound is heard, thus providing a method for testing the hearing of small children. This procedure is most appropriate for children in the 6-month to 3-year age range.