Ch. 10: Audiology & Hearing Disorders Flashcards Preview

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Flashcards in Ch. 10: Audiology & Hearing Disorders Deck (133):
1

Outer Ear

Composed of the auricle/pinna and external auditory canal (or external auditory meatus/EAM).

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Auricle/Pinna

Funnels sound to the ear canal and helps localize sound. Most visible part of the ear. Composed primarily of cartilage.

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External Auditory Canal

Goes from the pinna to the tympanic membrane/eardrum. Muscular tube made mostly of cartilage. Curves slightly like an S. Has special cells that secrete cerumen.

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Cerumen

Functions of this substance include lubricating and cleansing the ear canal, and protecting the ear from fungi or small insects. Excreted from cells in the external auditory canal.

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Middle Ear

Air-filled cavity that is separated from the outer ear by the tympanic membrane. Houses three tiny bones to form the ossicular chain. Eustachian tube connects this area to the nasopharynx.

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Tympanic Membrane

Membrane that is elastic, thin, and cone-shaped. It is flexible and tough and vibrates in response to sound pressure. The entire structure responds to low-frequency sounds, but only certain portions respond to high-frequency sounds.

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Ossicular Chain

Structure housed in the middle ear y ligaments. Composed of three tiny bones: the incus, malleus, and stapes. Transmits sound efficiently with no distortion. Amplifies incoming sound by approximately 30 dB before transmitting it to the fluids of the inner ear.

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Malleus

Largest ossicle. Resembles a hammer. Embedded in the TM. Because of this attachment, the vibrations of the TM are transmitted to this structure. Attached to the incus.

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Incus

Connected to the malleus and stapes by a tight joint that permits very little movement. Shaped like an anvil.

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Stapes

Ossicle that looks like a footplate or stirrup. The footplate is inserted into the oval window.

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Oval Window

Small area in the middle ear that leads to the inner ear. Small opening in the temporal bone that houses the inner ear.

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Tensor Tympani & Stapedius Muscles

Muscles in the middle ear that dampen the vibrations of the TM and the ossicular chain.

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Tensor Tympani

Muscle that tenses the TM so that its vibrations are reduced. Innervated by CN V.

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Stapedius Muscle

Stiffens the ossicular chain so that its vibrations are reduced. Innervated by CN VII. Smallest muscle in the body.

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Acoustic Reflex

Stiffens the middle ear system, especially the TM, in response to very loud sounds as a protection mechanism.

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Eustachian Tube

Helps maintain equal air pressure within and outside the middle ear. Connects the middle ear with the nasopharynx. Goes from the anterior middle ear wall to the posterior wall of the nasopharynx. The nasopharyngeal end of this structure can be opened by yawning or swallowing. This ventilates the middle ear by letting in fresh air. Contracts with the help of the tensor veli palatini and the levator veli palatini. Can allow germs and infections to spread to the middle ear, potentially causing infections.

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Inner Ear

A system of interconnecting tunnels (labyrinths) within the temporal bone. Begins with the oval window. Includes the vestibular system and the cochlea.

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Perilymph

Fluid that fills the labyrinths of the inner ear.

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Vestibular System

System within the inner ear concerned with balance. Contains 3 semicircular canals. Related to movement, balance, and body posture.

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Semicircular Canals

Responsible for equilibrium.

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Cochlea

Snail-shaped, coiled tunnel that is filled with endolymph.

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Basilar Membrane

Floor of the cochlea duct. Contains the organ of Corti. Different portions of this structure respond best to sounds of different frequencies. The tip is thick, wide, and lax—ideal for low-frequency sounds. The base is thin narrow, and stiff—ideal for high-frequency sounds.

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Organ of Corti

Located in basilar membrane. Bathed in endolymph and contains several thousand hair cells (cilia), which respond to sound vibrations.

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15,500 Hair Cells

Number of hair cells contained in the organ of Corti of each ear.

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Reissner’s Membrane

Allows transmission of wavelike movements in perilymph from stapes vibrations in the oval window to the endolymph. The endolymph then transmits the movements to the basilar membrane.

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Cranial Nerve VIII

Picks up the neural impulses created by the movement of hair cells in the cochlea. A bundle of neurons with two branches. Vestibular branch → equilibrium. Auditory branch → supplies many hair cells of the cochlea and conducts electrical sound impulses from the cochlea to the brain. Has contralateral and ipsilateral pathways.

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Cerebellopontine Angle

Where the auditory nerve exits the temporal bone through the internal auditory meatus and enters the brain stem.

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Docussate

To cross over.

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Primary Auditory Area of the Temporal Lobe

Area of the brain where sound is interpreted.

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Acoustics

A branch of physics that is the study of sound as a physical event.

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Psychoacoustics

The study of sound as the psychological experience of hearing.

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Mediums

Areas that sound waves travel through (e.g., gas, liquid, solid). Must be elastic to carry sound.

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Cycles

Repeated patterns of movement that are measure per second. How vibrations occur.

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Frequency

Refers to the number of times a cycle vibration repeats itself within a second.

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Pure Tone

A tone of a single frequency.

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Simple Harmonic Motion/Sinusoidal Motion

A tone of a single frequency that repeats itself.

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Complex Tone

Created by two or more sounds of differing frequencies.

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Periodic Vibrations

Vibrations that have a pattern that repeats itself at regular intervals until it is stopped by external action.

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Aperiodic Vibrations

Vibrations that do not have a repeating pattern and occur at irregular intervals.

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Sound Waves

Displacement of air molecules, causing them to move.

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Hertz (Hz)

Refers to cycles per second.

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Compression

When air molecules are packed tightly together.

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Rarefaction

When air molecules are farther apart. Also known as expansion.

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Pitch

Perceptual correlate of changes in frequency.

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Intensity

Perceptual correlate of the loudness of sounds.

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Amplitude

Extent of displacement of the molecules in their to-and-fro motion. The greater the range of displacement, the greater this becomes.

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Decibel (dB)

Measure of sound pressure. Measures the intensity of one sound against another.

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Sound Pressure Level (SPL)

The intensity of a sound expressed in terms of dB.

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Hearing Level (HL)

The lowest intensity of a sound necessary to stimulate the auditory system. Measured in dB.

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Air Conduction

In this process, sound waves strike the TM. The movement of the TM causes the ossicles to move, creating movement of the fluids of the inner ear. These movements cause vibrations in the basilar membrane of the cochlea. The hair cells supplied by the acoustic nerve respond to these vibrations, and the sound is carried to the brain by the acoustic nerve. In this process, sound travels through the medium of air.

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Bone Conduction

In this process, the bones of the skull vibrate in response to airborne sound waves, causing movements in the inner ear fluids. Sound travels through the medium of bone.

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Conductive Hearing Loss

In this type of HL, the efficiency with which the sound is conducted to the middle or inner ear is diminished.

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Up to 15 dB

Normal hearing in children. In adults the upper limit of hearing may extend to 25 dB.

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16 – 40 dB

Mild hearing loss in children. Difficulty hearing faint or distant speech. May cause language delay in children. In adults the range is between 25 – 40 dB.

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41 – 55 dB

Moderate hearing loss. Delayed speech and language acquisition. Difficulty in producing certain speech sounds correctly. Difficulty following conversation.

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56 – 70 dB

Moderately severe hearing loss. Can understand only amplified or shouted speech.

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71 – 90 dB

Severe hearing loss. Difficulty understanding even loud and amplified speech. Significant difficulty in learning and producing intelligible oral language.

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91+ dB

Profound hearing loss. Typically described as deaf. Hearing does not play a major role in learning, producing, and understanding spoken speech and language.

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Aural Atresia

Condition in which the external ear is completely closed.

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Microtia

Condition in which the pinna is very small and deformed. Often accompanied by aural atresia.

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Stenosis

Condition which results in an extremely narrow external auditory canal. Sound waves may not strike the TM.

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External Otitis

Infection of the skin of the external auditory canal. Often caused by bacteria or viruses. Commonly found in swimmers. Results in the swelling of the tissue of the canal. Sound transmission is reduced.

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Otitis Media

Infection of the middle ear that is often associated with upper-respiratory infections and Eustachian tube dysfunction. Occurs frequently in infants and children but rarely in adults. Usually creates a conductive hearing loss of 20 – 35 dB HL. Also known as middle ear effusion.

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Serous Otits Media

Middle ear is inflamed and filled with watery or thick fluid. The Eustachian tube is blocked and thus does not allow fresh air to ventilate the middle ear. The middle ear thus becomes airtight; soon the air inside is thinned out and the pressure is reduced.

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Pressure Equalizing (PE) Tubes

Tiny tubes inserted through the TM, ventilating the ear and restoring hearing in children with chronic otitis media.

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Acute Otitis Media

Sudden onset of otitis media due to infection. A quick buildup of fluid and pus causes moderate to severe pain. The child has a fever and may experience vertigo. The buildup of pressure in the middle ear may rupture the TM, giving instant relief as pus is discharged from the ruptured membrane.

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Myringoplasty

Surgical procedure to repair a perforated TM.

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Otosclerosis

A common cause of conductive hearing loss. Ossicles become rigid and unmoving. May be inherited and is more common in women.

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Carhart’s Notch

A pattern of bone conduction thresholds characterized by reduced bone-conduction sensitivity predominantly at 2000 Hz. Commonly seen in patients with otosclerosis.

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Otospongiosis

A disease that causes the stapes to become too soft to vibrate. The diseased or fixated stapes is surgically removed in a procedure called a stapedectomy.

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Stapedectomy

A surgical procedure to remove the stapes. A synthetic prosthetic of wire or Teflon replaces the removed stapes, often dramatically improving hearing postsurgically.

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Ossicular Discontinuity

Disarticulation of the ossicular chain.

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Sensorineural Hearing Loss

In this type of hearing loss, the middle ear may conduct the sound efficiently to the inner eat, but damage to the hair cells of the cochlea or to the acoustic nerve prevents the brain from receiving the neural impulses of sound. It is permanent because the damaged hair cells and the acoustic nerve are not repairable. Both bone and air conduction are impaired.

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Recruitment

Potential symptom of SNHL. Refers to a disproportionate increase in growth of perception of the loudness of sound when it is presented with linear increases in intensity. This makes a person hypersensitive to intense sounds and must be considered during HA fitting.

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Acoustic Neuroma

Tumor on the acoustic nerve that can cause sensorineural loss by slowing nerve conduction of sound impulses to the brain.

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Presbycusis

Age-related hearing loss. Affects the higher frequencies most commonly. Patients often have difficulties with recognition of speech, especially under challenging listening conditions such as noisy parties.

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Meniere’s Disease

A condition that causes fluctuating SNHL, usually in adults. It is attributed to excessive endolymphatic fluid pressure in the membranous labyrinth, which causes Reissner’s membrane to become distended. Symptoms include hearing loss, spells of dizziness or vertigo, a sense of fullness in the ears, and tinnitus. No cure for this disease.

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Mixed Hearing Loss

Type of hearing loss that occurs when neither the middle ear nor the inner ear is functioning properly. May be caused by the presence of two separate disorders in the same ear.

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Central Auditory System

System that includes the brainstem, where the auditory nerve terminates, the fibers that project sound to the auditory centers of the brain, and those brain centers themselves.

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Central Auditory Processing

Refers to the effectiveness and efficiency with which the central nervous system utilizes auditory information.

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Peripheral Hearing Problems

Results from problems in the outer, middle, or inner ear (excluding the auditory nerve).

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Central Auditory Disorders

Refers to the hearing losses due to disrupted sound transmission between the brainstem and the cerebrum as a result of damage or malformation. The temporal cortex of the brain may receive incorrect information, or the person may process information incorrectly. Controversial. Patient may have no peripheral hearing loss. Major symptom is difficulty understanding distorted speech.

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Central Auditory Processing Disorder

Disorder in a person’s ability to take in the spoken message, interpret it, and make it meaningful.

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Dichotic Listening Task

Task in which the listener must process different messages presented simultaneously to both ears. Used to diagnose central auditory disorders.

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Retrocochlear Disorder

Damage to the nerve fibers along the ascending auditory pathways from the internal auditory meatus to the cortex. Associated with cerebellopontine angle and cranial nerve VIII pathologies. Typically caused by unilateral tumors or acoustic neuromas. Patient experiences a unilateral high frequency hearing loss accompanied by tinnitus and dizziness. Acoustic reflexes are either absent or present at elevated levels. Patient may experience alterations of facial sensation and movement.

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Von Recklinghausen Disease

An inherited disease characterized by the presence of numerous small tumors that grow slowly and occur along various peripheral nerves. When they grow along CN VIII, they may initially be mistaken for an acoustic neuroma. Patients with this disease may die if the tumor becomes malignant.

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Audiometer

An electronic instrument that generates and amplifies pure tones, noise, and other stimuli for testing hearing.

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Pure-Tone Hearing Test

A hearing test is carried out to determine the threshold of hearing for selected frequencies.

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Threshold

An intensity level at which a tone is faintly heard at least 50% of the time it is presented. Each tone is presented several times to reliably establish a threshold.

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Bone-Conduction Testing

Hearing testing that assesses the sensitivity of the sensorineural portion of the auditory mechanism. A bone vibrator is placed on the forehead or behind the test ear. When the sound strikes the bones of skull, the bones vibrate and thus stimulate the fluid in both inner ears. It is difficult to determine which ear(s) heard the sound.

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Masking

Procedure in which nose is sent through a headphone at a level that is strong enough to mask the tone heard in the opposite ear.

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Speech Audiometry

Measures how well a person understands speech and discriminates between speech sounds.

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Speech Reception Threshold

The lowest level of hearing at which the person can understand 50% of the words presented. Uses a list of spondee words.

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Spondee

Two-syllable word with equal stress on each syllable (e.g., hotdog, baseball).

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Word Discrimination/Word Recognition Test

Test that establishes how well a person discriminates between words by having the person correctly repeat monosyllabic words such as cap and day. Words are presented at a level of loudness that is comfortable for the patient because this is not a test of hearing thresholds. Reported as a percentage.

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Acoustic Immitance

A transfer of acoustic energy. An energy transformation takes place when a sound stimulus reaches the external ear canal and strikes the TM.

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Impedance

Resistance. Often provided by the TM and middle eat structures.

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Admittance

A measure of the amount of energy that flows through the system.

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Tympanometry

A procedure in which acoustic immitance is measured with an electroacoustic instrument called an impedance bridge/meter. Also measures positive and negative changes in the ear canal.

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Acoustic Reflex

A simple reflex response of the muscles attached to the stapes bone. Reflex response involves a stiffening of the ossicular chain, presumably to protect the ear from potential damage.

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Electrophysiological Audiometry

An objective measure of auditory mechanism function. In response to sound, the cochlea, acoustic nerve, and auditory centers of the brain generate measurable electrical impulses. These impulses are recorded as changes in the background electrical activity in the brain.

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Auditory-Evoked Potentials

Electrical changes produced by sound stimuli. Usually, abnormal patterns of electrical activity in reaction to a sound stimulus indicate a hearing loss.

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Electroencephalography

The procedure for measuring the electrical activity of the cochlea in response to sound. The ECoG generated by this testing is a resonse consisting primarily of the compound action potential that occurs at the distal portion of CN VIII. Most useful in monitoring cochlear function in operating rooms to simplify the placement of electrodes.

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Auditory Brainstem Response (ABR)

A technique used to record the electrical activity in the auditory nerve, the brainstem, and the cortical areas of the brain. Useful in detecting brainstem diseases. Helpful in testing the hearing of newborns.

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Localization Audiometry

Hearing testing that involved presenting a sound and seeing if the infant will turn his or her heard toward the sound. This response is measured by presenting sound from different directions and noting the infant’s response.

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Operant Audiometry

A child’s hearing is tested by conditioning voluntary responses to sound stimuli.

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Air-Bone Gap

Gap on an audiogram that indicates that a hearing loss is conductive.

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Congenital Hearing Loss

Hearing loss present at birth. Have a greater impact than acquired hearing losses.

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Aural Rehabilitation

An educational and clinical program implemented primarily by audiologists. Designed to help people with hearing losses achieve their full potential.

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Traditional Hearing Aids

Small electronic devices that are worn inside the ear unilaterally or bilaterally depending on the needs of the person. Amplify sound and deliver it to the ear canal. An earmold is necessary for this device.

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Analog Hearing Aids

A common type of HAs that create patterns of electric voltage that correspond to the sound input. Consist of a microphone, an amplifier, a receiver, a power source (batteries), and volume control.

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HA Transducer

Part of a HA that converts the sound energy into electrical energy (microphone to receiver).

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Amplifier

Part of the HA that increases electrical signals and delivers them to the receiver.

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Digital Hearing Aid

HA that contains microcomputer technology. Rapidly samples the input signal and converts each sample into a binary system of zeros and ones. Those numbers are then processed by a computer houses in a unit worn on the body. Provide better signal-to-noise ratio. Effective in reducing irritating background noise.

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Signal-to-Noise Ratio

Separation of speech from background noise.

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Bone-Conduction Hearing Aids

Amplify sound for the patient using a bone-conduction vibrator.

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Cochlear Implants

Electronic devices that are surgically based in the cochlea and other parts of the ear, and deliver the sound directly to the acoustic nerve endings in the cochlea. Delivers electrical impulses, converted from sound, directly to the auditory nerve. Replace the nonfunctioning inner hair cell transducer system. Consist of a microphone, processor, external transmitter, and implanted receiver.

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Central Electroauditory Prosthesis

Current development in cochlear implant technology. Directly stimulates the cochlear nucleus of the auditory nerve at the brainstem level.

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Tactile Aids

A type of sensory substitution method use for individuals who are deaf. Promote the comprehension of speech by means of touch. Sometimes used for individuals with profound deafness and individuals who are both deaf and blind. Convert sound into tactile stimulation.

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Tacoma Method

A manual system for people who are deaf and blind, involves them placing hands on the speaker’s face to the feel the vibrations of speech. Listener feels the vibrations of the lips, cheeks, jaws, and vocal folds of the speakers. Listener also feels nasal and oral airflow.

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Auditory Training

Designed to teach a person with hearing impairment to listen to amplified sounds, recognize their meanings, and discriminate sounds from each other.

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FM Auditory Trainer

A wireless system that can be used in group or individual treatment sessions. The child and teacher both wear receiving and transmitting units to they can hear and talk with each other.

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Speech Reading

Involves deciphering speech by looking at the face of the speaker and using visual cues to understand what the speaker is saying. Previously called lip reading.

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Homophenous

Words that look the same while speech reading and may be confusing to the listener.

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Cued Speech

Speech produced with manual cues that represent the sounds of speech. May be used to supplement speech reading. Composed of 8 signs or hand configurations for consonants and 4 signs for vowels.

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Auditory-Oral Method

Method of auditory training that uses amplification methods such as hearing aids or cochlear implants to tap children’s residual hearing. Children undergo intensive auditory training and speech reading instruction. It is expected that they will eventually learn to speak and will fit into mainstream social, vocational, and educational settings.

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Manual Approach

A means of nonverbal communication that involves signing and fingerspelling. Proponents believe that early in life, children who are deaf must be taught a comprehensive sign language system. This system is viewed as part of the Deaf culture and is the standard means of communication in the community of people who are deaf. Therefore, children who are deaf learn not only a means of communication, but also a way of integrating into that community.

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Total Communication

Involves teaching both verbal and nonverbal means of communication. Signs and speech are used simultaneously. People who are deaf are taught speech and language along with a sign system. There is no attempt to tap residual hearing through amplification.

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American Sign Language (ASL)

Viewed as a separate language from manual English. Signs are used to express ideas and concepts through complex hand and finger movements.

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Seeing Essential English (SEE 1)

Primarily employs ASL. Breaks down words into morphemes and uses written English word order. Uses some markers to help identify number and tense, and also uses specific signs for some verbs and articles.

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Signing Exact English (SEE 2)

Similar to SEE 1 but used more widely. More flexible about precise word order in sentences. Breaks down words into morphemes that are words when they stand alone.

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Fingerspelling

Ideas are communicated through quick, precise movements made by the fingers. May be used alone or in conjunction with methods like ASL. Sometimes it is used for unusual words that do not have standard signs.

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Rochester Method

Uses a combination of oral speech and fingerspelling. Signs are not used in this method. The oral method is traditional English.