Tactile responses: The response obtained during bone-conduction (and occasionally air-conduction) audiometry to signals that have been felt, rather than heard by the patient.
Tactiles: Touching behaviors.
Tangible reinforcement operant conditioning audiometry (TROCA): A form of operant audiometry using tangible reinforcers, such as food or tokens.
Tardive dyskinesia: Involuntary, repetitive facial, tongue, or limb movements that sometimes occur as a side effect of certain medications.
TBI: See Traumatic brain injury.
Tectorial membrane: A gelatinous, tongue-shaped membrane above the organ of Corti in the scala media, in which the tips of the cilia of the hair cells are imbedded.
Teletypewriter (TTY): A device connected to a telephone by a special adapter; allows communication between persons who are hearing impaired and those who are not.
Temporal lobe: The part of the cerebral hemispheres usually associated with perception of sound. The auditory language areas are located in the temporal lobes.
Temporary threshold shift (TTS): Temporary sensorineural hearing loss, usually associated with exposure to intense noise.
Temporomandibular joint (TMJ) syndrome: Pain felt in the ear, but referred from a neuralgia of the temporomandibular joint.
Tensor tympani muscle: A small muscle, innervated by the trigeminal nerve, and inserted into the malleus in the middle ear.
Tensor tympani muscle: One of two small muscles in the middle ear that contract in response to intense acoustic stimulation.
Teratogens: Chemical or environmental agents that produce congenital abnormalities.
Tetrachoric table: A table containing four cells designed to test the efficiency and accuracy of group hearing tests.
Thalamus: A pair of spherical neural structures located in the brain base, the thalamus sends projecting fibers to, and receives fibers from, all parts of the cortex.
Thoracic vertebrae: Twelve individual vertebrae located immediately beneath the cervical vertebrae.
Thorax: The chest area between the neck and abdomen.
Threshold of discomfort (TD): See Uncomfortable loudness level.
Threshold: In audiology, the least audible sound-pressure level; often defined operationally as the level of a sound (in decibels) at which it can be heard by an individual 50 percent of the time.
Thrombosis: A blood clot within a blood vessel of the body. It may result in an ischemic stroke.
Thyrohyoid membrane: Membrane extending from the hyoid bone to the thyroid cartilage.
Thyrohyoid muscle: Extrinsic muscle of the larynx that pulls the larynx upward.
Thyroid cartilage: "V" shaped largest cartilage of the larynx.
Thyromuscularis muscle: Lateral bundle of the thyroarytenoid muscle.
Thyrovocalis muscle: Medial bundle of the thyroarytenoid muscle.
Tics: Involuntary, rapid and repetitive, stereotypic movements.
Tidal breathing: Breathing to sustain life.
Time-compressed speech: A system of recording speech so that it is accelerated and therefore distorted, but the words remain discriminable.
Timing: Accuracy of the beginning and ending of a muscle contraction and the duration of that contraction.
Tinnitus
Ear or head noises, usually described as ringing, roaring, or hissing.
Tolerance level: See Uncomfortable loudness level.
Tone decay: The loss of audibility of a sound produced when the ear is constantly stimulated by a pure tone.
Tone: Resistance to stretch; the near constant state of a muscle.
Tongue thrust: Swallowing with a forward movement of the tongue, resulting in misarticulation of various phonemes. Also known as myofunctional disorder.
Tonotopic: Arranged anatomically according to best frequency of stimulation.
Tonotopically arranged: Refers to the basilar membrane in which different areas respond differently to different frequencies of sound.
Total communication: The use of sign, amplification, and speech in the communication training of individuals with deafness.
Toynbee maneuver: A method for forcing the eustachian tube open by swallowing with the nostrils and jaw closed.
Trachea: Cartilaginous tube extending from the larynx to the lungs via the bronchi.
Tracheo-esophageal shunt: A device that directs air from the trachea to the esophagus for esophageal speech.
Tracheostomy tube: A tube that is inserted into the trachea to relieve a breathing obstruction.
Tracheostomy: An opening through the neck into the trachea through which a tube is placed to reduce the risk of aspiration.
Transcortical motor aphasia: A nonfluent aphasia that is characterized by impaired conversational speech, good verbal imitative abilities, and mildly impaired auditory comprehension.
Transcortical sensory aphasia: A rare fluent aphasia that is characterized by word substitutions, lack of nouns and severe anomia, and poor auditory comprehension, but ability to repeat or imitate words, phrases and sentences.
Transduce: To convert one form of power to another (e.g., pressure waves to electricity, as in a microphone).
Transient-evoked otoacoustic emission (TEOAE): An otoacoustic emission evoked in the cochlea by very brief acoustic stimuli like clicks or tone pips.
Transistor: An electronic device, with low power consumption and small space requirements, that amplifies electric current through the use of the semiconducting properties of an element such as silicon.
Transverse abdominis: Abdominal muscle that can assist in forced exhalation.
Transverse muscle (tongue): Intrinsic tongue muscle that elongates the tongue.
Transverse wave: A wave in which the motion of the molecules of the medium is perpendicular to the direction of the wave.
Trapezoid body: Nerve fibers in the pons that connect the ventral cochlear nucleus on one side of the brain with the lateral lemniscus on the other side.
Traumatic brain injury (TBI): Damage to the brain resulting from bruising and laceration caused by forceful contact with the relatively rough inner surfaces of the skull or from secondary edema or swelling, infarction or death of tissue, and hematoma or focal bleeding.
Traveling wave theory: The theory that sound waves move in the cochlea from its base to its apex along the basilar membrane. The crest of the wave resonates at a particular point on the basilar membrane, resulting in the perception of a specific pitch.
Treacher Collins syndrome: An inherited disorder that is characterized by excessive muscle tone in the face and jaw.
Treatment plan: Recommendations for addressing the problem, including placement, therapy approaches, counseling suggestions, and referrals.
Tremors: Involuntary, rhythmic movements caused by contractions of antagonistic muscles.
Trigeminal nerve: The Vth cranial nerve, which innervates the tensor tympani and also some of the palatal muscles.
Trisomy: The presence of an additional (third) chromosome.
Tuning fork: A metal instrument with a stem and two tines. When struck, it vibrates, producing an audible, near-perfect tone.
Tympanic membrane: The cone-shaped separation between the outer and middle ears, located at the end of the external auditory canal. It comprises an outer layer of skin, a middle layer of connective tissue, and an inner layer of mucous membrane. It completely closes off one end of the ear canal so that all of the incoming sound vibrations strike its surface (eardrum).
Tympanogram: The graph generated by a tympanometer during immittance testing that depicts compliance of the eardrum relative to changes in air pressure.
Tympanometer: Audiometric equipment that is used to assess the compliance of the tympanic membrane.
Tympanoplasty: A surgical procedure designed to restore the hearing function to a middle ear that has been partially destroyed (as by otitis media).
Tympanosclerosis: Formation of whitish plaques in the tympanic membrane and masses of hard connective tissue around the bones of the middle ear. This occurs secondary to otitis media and may result in fixation of the ossicular chain.
Type I error: See False positive.
Type II error: See False negative.
Vacuum tube: A glass enclosure designed to regulate the flow of electric current.
Validity: In tests, the accuracy with which the instrument measures what it intends or claims to measure.
Valsalva: Autoinflation of the middle ear by closing off the mouth and nose and forcing air up the eustachian tube.
Variable expressivity: The extent to which an inheritable trait is manifested.
Variable pure-tone average (VPTA): The average pure-tone threshold of the poorest three frequencies of 500, 1000, 2000, and 4000 Hz, used for the assignment of hearing loss impairment labels. Allows for a representation of hearing loss of either flat configuration or isolated primarily within either the lower or higher frequency range.
Variegated babbling: Long strings of consonant-vowel syllables, in which adjacent and successive syllables in the string are not identical.
Varying Intensity Story Test (VIST): Portions of a story are presented above the admitted "threshold" and portions below. If the patient remembers information presented below the admitted threshold, this is prima facie evidence that the hearing loss in that ear is exaggerated.
Vasiculation: Rapid, random, irregular, and minute contractions of nerve bundles.
Vasospasm: The violent constriction of a blood vessel, usually an artery.
Velocity: The speed of a sound wave in a given direction.
Velopharyngeal competence: Adequate closure of the velopharyngeal portal (soft palate and back of throat) during swallowing and speech production.
Velopharyngeal incompetence (VPI): Inability of the velopharyngeal mechanism to separate the oral and nasal cavities during swallowing and speech.
Velopharyngeal mechanism: Velum (soft palate) and walls of pharynx (back of throat), used to close the velopharyngeal portal.
Velopharyngeal portal: Opening or the conduit connecting the oral and nasal cavities.
Velum: The soft palate, which constitutes the posterior one third of the palate.
Ventral cochlear nucleus: The larger of the two cochlear nuclei on each side of the brain; it receives the fibers of the cochlea on the ipsilateral side.
Verbal stereotype: An expression that is repeated over and over; characteristic of some individuals with aphasia.
Vermilion: Pinkish to brown coloration of the lips.
Vertebral column: The backbone comprised of thirty-two separate vertebrae.
Vertical muscle: Intrinsic tongue muscle that flattens the tongue.
Vertigo: The sensation that a person (or his or her surroundings) is whirling or spinning.
Vestibule: The cavity of the inner ear containing the organs of equilibrium and giving access to the cochlea.
Vibration: A series of rapid, rhythmic, back-and-forth movements. In a free vibration the mass is displaced from its position of rest and allowed to oscillate without outside influence. In a forced vibration the mass is moved back and forth by applying an external force.
Vibrotactile aids: Devices that deliver amplified vibratory energy to the surface of the skin by special transducers. They are designed for patients whose hearing losses are so severe that assistance in speechreading cannot be obtained from traditional hearing aids.
Videofluoroscopy : See Modified barium swallow study.
Visceral pleura: Serous membrane that lines the lungs and thoracic cavity.
Visual reinforcement audiometry (VRA): A method of hearing testing in which a child, often as young as three to four months, is rewarded for looking for a sound by the use of moving toys and/or flashing lights.
Vocal abuse: Any of several behaviors, including smoking and yelling, that can result in damage to the laryngeal mechanism.
Vocal fold paralysis: Immobilized vocal fold usually due to nerve damage.
Vocal hygiene: Proper care of the voice.
Vocal nodules: Localized growths on the vocal folds that are associated with vocal abuse.
Vocal polyp: A fluid-filled lesion of the vocal fold that results from mechanical stress.
Vocal tremor: Variations in the pitch and loudness of the voice that are involuntary.
Voice: Vocal tone and resonance.
Voiced: Vocal fold vibration; phonemes that are produced with vocal fold (laryngeal) vibration.
Voiceless: Without vocal fold vibration; phonemes that are produced without vocal fold (laryngeal) vibration.
Voicing: Laryngeal vibration.
Volley theory of hearing: A variation of the frequency theory in which some neurons fire during the refractory periods of other neurons.
Vowel: Any of several voiced phonemes that are produced with a relatively open vocal tract.
