SPHS-S 110 : EXAM 2
87 Cards in this Set
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vowel sounds
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periodic
longer in duration than consonant sounds lower in frequency than most consonants
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consonant sounds
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periodic/aperiodic
very short in duration higher in frequency than most vowels
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middle ear
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the air-filled space located in the temporal bone containin the three small middle-ear bones, incus, malleus, and stapes
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eustachian tube
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a stirrup-shaped bone within the middle ear that attaches to the round window of the inner ear
vibrates and is transmitted through cochlear fluids within the organ of corti
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outer ear function
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-resonance and sound funneling
-sound localization -protection for outer and middle ear -covered in cerumin (wax) and hair
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cochlea
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the snail-shaped part of the inner ear containing the sensory organs for hearing
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ossicles
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the three small bones (incus, malleus, stapes) that form the ossicular chain in the middle ear
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oval window
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a membrane-covered opening of the vestibule of the cochlea that is attached to the footplate of the stapes, vibration of the stapes footplate sets the oval window in vibration
provides amplification because of the vibration!
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pinna
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the visible outer ear, also known as the auricle
compromised of cartilage and skin
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inner ear components
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1) vestibule
2) semicircular canals 3) cochlea
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inner ear
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where hearing (and balance) begins!!
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middle ear purpose
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over come the difference in impedance between air and the fluid-filled head
achieved by: air difference and lever action protects from loud sounds achieved by the two smallest muscles in the human body: tensor tampani and stapedius
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impedance
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opposition to the flow of energy
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impedance of fluid is greater than...
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the impedance of air
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maleus
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a hammer-shaped bone attached to the tympanic membrane within the inner ear
creates leverage within the incus!
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leverage
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produced between the malleus and the incus
malleus is longer than the incus and the difference in length creates leverage (less energy is needed to move the incus and hence the stapes)
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scala media
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(aka Cochlear Duct) contains the organ of hearing
located in the inner ear
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concha
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located in the outer ear... helps provide resonance (amplification) to incoming sound
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tympanic membrane
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thin, translucent barrier between ear canal and middle ear space
vibrates in response to sound air pressure must be equal on both sides of the TM for it to vibrate properly in response to sound
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modiolus
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the center of the bony spiral structure of the cochlea
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incus
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an anvil-shaped bone found in the middle ear
helps with leverage along with the malus
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scala vestibuli
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connects to the oval window
located in the inner ear
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round window
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an opening in the vestibule of the cochlea beneath the oval window on the cochlea, permitting the displacement of movement of fluid within the cochlea
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organ of corti
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area within the cochlea containing the tectoral membrane and hair cells
transduces vibrations in fluid produced by sound into neural impulses
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travelling wave
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vibration along the basilar membrane
- vibrating stapes footplate produces a wave in fluid-filled cochlea - distance wave travels from the stapes varies with sound frequency tonotopic organization is accomplished because of the travelling wave
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dynamic range
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an effect of the cochlear amplifier and allows us to perceive lower amplitude sounds then we could with no amplifier
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semicircular canals
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located in the inner ear
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basiliar membrane
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a thin tissue layer found within the cochlea on which the organ of corti rests
said to be frequency selective or have tonotopic organization
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basiliar membrane function
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forier analysis: complex sounds are decomposed into their component frequencies (pure tones)
How? combination of stiffness gradient and mass gradient
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stereocillia
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site of mechano-transduction i.e., the translation of the sound vibration into a nervous message which the brain can interpret
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inner hair cells
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one row
responsible for producing our sensation of hearing loss or damage results in severe to profound hearing loss
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cochlear amplifier
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a positive feedback mechanism:
it is stimulated by the motion of the BM, which in turn causes it to add to the motion of the BM
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effects of the cochlear amplifier
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1) widens our dynamic range
2) sharpens frequency selectivity 3) produces otoacoustic emissions
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otoacoustic emissions
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sounds produced by the inner ear- used to clinically determine cochlear health
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scala tympani
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connects to the round window in the inner ear
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outer hair cells
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three rows of approx. 12000
contain stereocillia and ion channels just like inner hair cells, BUT do NOT send information to the auditory nerve! -do not produce sensation of hearing -do not cause severe hearing loss or deafness if lost or damaged
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outer hair cells "special" property
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they can move!!
depolarized (more +)=shorten hyperpolarized (more -)=lengthen
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tonotopic organization
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cochlea maps sound frequency to place of sensory activity in the inner ear (basilar membrane function)
tono- frequency topic- place accomplished through the travelling wave
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conductive hearing loss
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indicates problem with sound transmission through the outer and/or middle ear
-if BC thresholds are in the normal range but the AC thresholds are elevated
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sensorineural hearing loss
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indicates problem with the inner ear and/or auditory nerve
-if there is no difference between AC and BC thresholds but both are elevated relative to norrmal
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mixed hearing loss
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hearing loss has both conductive and sensorineural components
-if there is a difference between AC and BC thresholds and BC thresholds are elevated relative to normal
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cone of light
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the reflection from the otoscope's light
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audiometer
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electronic device used to present pure-tone sound waves of specified frequency of level to the patient
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speech reception threshold (SRT)
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component of speech audiometry
what is the lowest level at which speech can be recognized 50% of thte time? values should correspond well to AC thresholds
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pure tone audiometry
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- detection of presence of hearing loss
- determination of type of loss - determination of degree of loss - determination of configuration of loss
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speech audiometry
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completed using air conduction, almost never with bone conduction....
2 components: 1) speech reception threshold (SRT) 2) speech-understanding score or word recognition score (WRS)
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immittance
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a term describing the flow of energy through a system
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acoustic immittance testing
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looking for auditory system function not hearing
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air conduction (AC)
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sound travels through the outer and middle ears before entering the cochlea
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audiogram
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a graphic representation of the results of a hearing test with axes for hearing level and frequency
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word recognition score (WRS)
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helps to decide if a hearing aid will help a patient
dependent upon what happens if speech is brought above threshold levels and in noisy situations...speech recognition?
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otoscopy
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visual inspection of the outer ear and TM
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otoscope
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an instrument with a magnifying lens and a light designed to be inserted into the ear canal for the purposes of visual inspection
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bone conduction (BC)
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tests sensitivity of the inner ear and beyond to sound, bypassing transmission through the outer and middle ear
performed with the bone conduction vibrator
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tympanometry
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measurement of middle ear mobility
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(S)TORCH
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acronym for syphillis, toxoplasmosis, other, rubella, cytomegalovirus, and herpes simplex infections
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microtia
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deformed pinna
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stenosis
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narrowing of the canal
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atresia
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absence of an ear canal
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transducer
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an electrical device that presents sound stimuli to the patient
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tympanogram
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provide information about the peak pressure and the static (peak) admittance of the middle ear system
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threshold
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the level at which an auditory signal can be detected 50% of the time
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normal hearing
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thresholds at or below 15 dB at all test frequencies
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otitis media
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middle ear infection
more common in children than adults may occur with or without fluid build-up behind eardrum (effusion)
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electrophysiological tests
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test for infants
stimulate the auditory system and record the electrical or mechanical response of a specific region
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advantages to electrophysiological tests for infants
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- no behavioral response is required
- can isolate teh response of specific regions of the audiotory system
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disadvantages to electrophysiological tests for infants
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- not tests of hearing!
- only gives info about isolated areas of the auditory system rather than providing info about the auditory system as a whole
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genetic hearing loss
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hearing loss due to genetic factors
HL is rarely genetic...
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behavioral observation audiometry (BOA)
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-used primarily for neonates
-child's behavioral response is to auditory stimuli may include: -changes in sucking or respiration rate, or eye widening - typically can only identify infants with severe or profound hearing losses
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visual reinforcement audiometry (VRA)
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-used for children 5 months to 2 years of age
- tests speech, pure tones, or noise stimuli
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conditioned play audiometry (CPA)
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asses hearing acuity using conditioned responses to sound by engaging in play-oriented activities
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congenital hearing loss
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- present at birth but no genetic
examples: fetal alcohol syndrome, STORCH infections, etc.
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acquired hearing loss
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normal hearing at birth with HL acquired sometimes afterwards
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otosclerosis
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abnormal growth of bone of the middle ear- stapes becomes fixated in oval window (spongy bony growth)
-hereditary (60% family history) - hearing loss onset (15-45 yrs of age; starts usually at 20) -affects both ears (80% of patients) -affects women 2:1 -worsens rapidly during pregnancy
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menieres disease
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cochlear pathology:
endolymphatic hydrops dizziness fluctuating hearing loss poor word recognition
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presbyacusis
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cochlear pathology: happens with aging
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ototoxicity
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cochlear pathology: 'mycin, 'platin (medications)
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acoustic neuroma
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a nonmalignant tumor in the left internal auditory canal
-impact on reflexes -impact on speech understanding
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what hearing device?
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depends on many factors, but severity of hearing loss is the primary one
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hearing aids best for...
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mild to severe HL
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cochlear implants best for
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severe to profound HL
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sensorineural hearing loss
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the cochlea is damaged
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hearing aids
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attempt to compensate for the hearing loss by amplifying sound in frequency regions that correspond to the region of hearing loss
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acoustic reflexes
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triggered in response to loud sound
reflex causes the muscles of the middle ear to contract bilaterally, thereby stiffening the middle ear system and increasing impedance
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hearing aid frequency response
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a measure of the response gain of a hearing aid across frequencies when presented at a constant input level
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peripheral components of the auditory system
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conduction of sound:
-outer ear -middle ear sensory transduction and neural transmission -inner ear -auditory nerve
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central components
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brain stem & brain
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