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audiology
final
Question | Answer |
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audiologist | a professional by virtue of their academic degree, training and license and is uniquely qualified to identify, assess, diagnose and treat persons with hearing loss and balance disorders as well as prevent associated impairments |
stages of grief | denial, anger, bargaining, acceptance |
outer ear boundaries | up to the tympanic membrane |
middle ear boundaries | tympanic membrane up to the stapes footplate at the oval window |
energy in outer ear | conducts acoustic |
energy in middle ear | converts acoustic to mechanical |
energy in inner ear | converts mechanical to hydromechanical to electrochemical |
vestibulocochlear nerve | transmits electrochemical nerve impulses to the brain |
transducer | device that converts one form of energy to another |
pure tone average | average of the air conduction thresholds for a given ear at 500, 1000 and 2000 Hz |
procedure for pure tone threshold | 1. biological test 2. case history 3. otoscopic examination 4. strategically seat patient 5. give instructions 6. earphone placement 7. threshold search 8. repeat in other ear 9. bone conduction 10. speech testing |
1-3-6 rule | 1 month- screened 3 months- fully assessed 6 months- treatment has begun |
narrow band noise | noise created by bandpass filtering that is centered at a specific audiometric frequency |
VRA is for what ages? | 6 months- 2 years |
play audiometry is for what ages? | 2-5 years |
otoacoustic emissions | tiny sounds generated in the cochlea arising from the outer hair cells that can be measured in the ear canal |
auditory brainstem response | -brainwaves that is generated when the ear is stimulated with sound and is recorded by electrodes (neural response) |
signs of possible hearing loss in children | -delayed speech -lack of moto reflex -syndromes associated with hearing loss -learning disabilities/ delays |
auditory development 0-6 weeks | startle, eye blink or widen eyes in response to sound |
auditory development 6-7 months | head turns laterally toward a sound or speech |
auditory development 7-24 months | level of signals needed to elicit a head turn drops (child is able to respond at threshold with development) |
auditory development 25+ months | conditioned play audiometry possible |
methods to screen an infant's hearing | -otoacoustic emissions -auditory brainstem response -brainstem auditory evoked response |
speech recognition threshold | the minimum hearing level for speech at which an individual can recognize 50% of the speech material (use spondaic words, stay at 50 dB, no frequency involved) |
speech detection threshold | the minimum hearing level at which an individual can just discern the presence of speech material 50% of the time |
word/speech recognition test | assesses a client's ability to identify one syllable words that are presents at hearing levels above threshold (cross- check between pure tone) |
retrocochlear pathology | auditory dysfunction that is beyond the cochlea (in the auditory nerve or the brain stem) |
purposes of the pinna | cosmetics, sound collector, same side localization |
purpose of cerumen | repel water, trap dust and other debris, moisturize epithelium in ear canal, odor discourages insects, antibacterial, antifungal, antibiotic, cleanses ear canal |
how sound travels through the ear (up to the inner ear) | acoustic energy, in the form of sound waves, is channeled into the ear canal by the pinna. sound waves travel through the external ear canal and strike the tympanic membrane causing it to vibrate like a drum, changing the acoustic energy into mechanical |
anotia | missing auricle-surgical treatment |
microtia | abnormally small pinna- surgical treatment |
perichronditis | cauliflower ear; infection of skin and tissue surrounding the cartilage of the outer ear- treated with medicine |
preauricular fissure/fistula | small hole before tragus- medical treatment |
preauricular tag/cyst | skin tag or pit in front of tragus- medical treatment |
keloid | overabundance of collagen (skin cells) in response to trauma |
carcinoma | basal cell, malignant skin grown- medical treatment |
external otitis | infection, thickened skin on external ear and canal; fluid collects in tissue and causes tenderness (aka swimmer's ear) |
stenosis | narrowing of canal following trauma, infection or genetics/ aging |
atresia | absence of normal opening to the canal- surgical treatment |
exostosis | bone tumor attached to osseous portion of ear canal causes by cold water exposure |
osteoma | skin covered bone growth |
purposes of middle ear | conduction, transducer (acoustic to mechanical), amplifier, protection |
tegmen tympani | top layer of bone in middle ear space that separates it from the brain |
fundus tympani | thin layer of bone on the floor of the middle ear space that separates it from the jugular bone |
malleus | hammer; embedded into fibrous portion of tympanic membrane |
incus | anvil |
stapes | stirrup |
eustachian tube | separates middle ear from the back of the throat; acts like a valve; opening and closing of tube equalizes pressure on either side of tympanic membrane |
tensor tympani | attached to malleus, pulls bone against tympanic membrane |
stapedius | attached to stapes, pulls stapes out of oval window |
function of middle ear muscles | help maintain ossicles in proper position; protect inner ear from levels above 70 dB by contracting and decreasing energy amount |
acoustic reflex | response of stapedius muscle to sound; decreases amount of energy transferred to the inner ear when sound is above 70 dB |
impedence matching device- RATIO | difference in size between the eardrum and the oval window (thumbtack) |
impedence matching device- LEVER | malleus and incus create system, stapes moves much less that the TM but results in more force (crowbar) |
top left quadrant (right ear) | posterior- superior |
top right quadrant (right ear) | anterior- superior |
bottom left quadrant (right ear) | posterior inferior |
bottom right quadrant (right ear) | anterior inferior |
outer layer of tympanic membrane | cuticular |
middle layer of tympanic membrane | fibrous |
inner layer of tympanic membrane | mucousa |
pars flaccida | (floppy) upper 1/3 of tympanic membrane, no fibrous tissue, vibrates minimally |
pars tensa | (tense) lower 2/3 of tympanic membrane, has fibrous tissue, vibrates maximally |
otitis media with effusion | inflammation of inner ear with fluid drainage |
glue ear | negative middle ear pressure causes TM to retract |
TM perforation | may be caused by OME or barotrauma; repairs on its' own, often accompanied by otorrhea |
cholesteotoma | tumor in middle ear space |
ossicular chain discontinuity/ disarticulation | damage to ossicular chain, results from head trauma or direct trauma to tympanic membrane |
otosclerosis | laying down of new bone usually around stapes footplate |
tympanosclerosis | formation of whitish plaques on TM and connective tissue around ossicles |
sound | a type of vibratory energy resulting from pressure waves when force is applied to some object or system |
amplitude | point of maximum displacement from place of rest |
frequency | number of cycles in a designated time period |
velocity | speed at which sound travels (340 meters/second in air) |
phase | the relationship in time between two or more waves |
waveform | amplitude and time |
hertz | cycles per second |
decibel | measures intensity |
dB HL | hearing level- referenced to audiometric zero |
dB IL | intensity level- magnitude level relative to a reference power |
dB SL | sensation level- deibel referent based on patient's hearing threshold |
dB SPL | sound pressure level- amount of sound energy compared to a reference pressure |
dynamic range | decibel difference between the threshold of sensitivity and the loudness discomfort level |
audiometric zero | lowest SPL at which a pure tone at each of the audiometric frequencies is audible to the average normal hearing ear |
inverse square law | intensity of a sound decreases proportionally to he square of distance from a source |
frequencies that the human ear can hear | 20- 20,000 Hz |
frequencies that are important for speech | 250- 8,000 Hz |
effect of frequency on length | as length increases, frequency increases |
effect of frequency on mass | as mass increases, frequency decreases |
effect of frequency on stiffness | as stiffness increases, frequency increases |
utricle | membranous sac, part of balance apparatus located within the bony labyrinth (horizontal balance) |
saccule | sensory cells controlling vertical balance |
semicircular canals | contain endolymph and are surrounded by perilymph |
oval window | membrane covered opening leading from the middle ear to the inner ear |
round window | allows fluid in cochlea to move; closed off from middle ear by membrane |
cochlea | carves into temporal bone; contains organ of corti |
basilar membrane | fibrous membrane running the whole length of the cochlea that separates scala media and scala tympani |
reissner's membrane | inside the cochlea; separates scala media from scala vestibule; creates compartment for endolymph |
scala media | canal in the cochlea that contains the organ of corti, holds endolymph |
scala vestibuli | perilymph- filled cavity that lies immediately beyond the oval window; conducts sound vibrations to the scala media |
scala tympani | filled with perilymph, terminates at the round window |
outer hair cells | motie, efferent, "biological hearing aid," stimulated by soft sounds, usually damaged before IHC, damage may occur before being able to measure hearing loss |
inner hair cells | non motile, efferent, stimulated by moderate- level |
organ of corti | sense organ for hearing, contains rows of outer and inner hair cells that differ in shape and function |
tectorial membrane | roof that hangs over the organ of corti and has cilia from the outer hair cells embedded into it |
modiolis | central bony pillar of cochlea |
vestibular portion of the 8th nerve | directly beyond the oval window; contains structures that deal with balance |
cochlear portion of the 8th nerve | contains organ of corti, stapes footplate pumps in and out of the oval window causing a disturbance of the fluid in the cochlea, changing mechanical energy into hydraulic energy and causes basilar membrane and tectorial membrane to move |
stria vascularis | upper portion of the spiral ligament, produces endolymph |
stereocilia | rows of hairs at the top of hair cells |
endolymph | in scala media, consistency of molasses |
perilymph | in scala vestiboli and tympani, thin and watery |
afferent | neurons carrying info from cochlea to central auditory nervous system (brain), most contact the IHC |
efferent | neurons carrying info from brainstem back to hair cells (feedback loop) most contact the OHC |
oliviochochlear bundle | group of efferent cochlear nerve fibers |
tonotopicity | different frequencies result in different points of displacement of the basilar membrane |
bony labyrinth | rigid outer wall of the inner ear; consists of vestibule, semicircular canals and cochlea |
membranous labyrinth | located inside bony labyrinth, holds receptors or equilibrium, separated from bony walls by perilymph |
vertigo | room is spinning |
vestibular | pertaining to the potion of the inner ear related to balance |
nystagmus | pattern of eye movement characterized by a slow component in one direction and a fast component to the other direction |
noise induced hearing loss | typically results from high levels over a period of time, high frequencies affected first |
acoustic trauma | sudden impact of sound to cause physical damage (detaches organ of corti from basilar membrane |
ototoxicity | medicine that is poisonous to the ear; auditory or vestibular damage; results in bilateral sensorineural loss; high frequencies affected first |
presbycusis/ presbyacusis | progressive loss of hearing due to the aging process |
meniere's disease | caused by oversecretion or underabsorbtion of endolymph; infection, autoimmune conditions, tinnitus, vertigo, fluctuating unilateral hearing loss in low frequencies |
labyrinthitis | infection fo the labyrinths, can affect both auditory and vestibular mechanisms; sudden hearing loss and vertigo |