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103 Cards in this Set
- Front
- Back
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#1 and # 2 causes of hearing loss and why
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1) Aging; people are living longer, baby boomers are aging
2) Noise; permanent, preventable and cumulative, more noise in our society (machines, technology, traffic, etc) |
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Name 8 other causes of hearing loss
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smoking (gets into your bloodstream),
sex (male > female), poor diet, ototoxic drugs (chemotherapy), genetics (400+), head trauma, babies in NICU (machine hum, less oxygen because they're premature), circulatory diseases |
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What does the medical model aim to achieve?
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Instead of fixing society, they want to fix the person
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What does the holistic model aim to achieve?
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want to increase functioning for the person living in their environment
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What is the therapy model and what does it aim to achieve?
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the therapy is a place for both medical and holistic models to work together by working towards normalcy (medical aspect) and by working towards equity (level playing field) rather than equality (treating everyone the same) (sociocultural model)
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How was audiology born?
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Audiology was born out of SLP and ENT because many of the wounded world war 2 soldiers came back with hearing loss (loud weapons and advanced technology)
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What are the 2 ways we hear sound?
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Air conduction: sound waves > outer ear> middle ear>inner ear> nerve> brain
bone conduction: sound vibrates skull >inner ear>nerve>brain (BC bypasses outer and middle ear) |
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what is the function of the outer ear? what are the structures
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pinna: to collect and resonate sound from environment, protect rest of the ear
External auditory meatus (ear canal): localizes sound to tympanic membrane, efficient for higher frequencies (smaller waves) |
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what is anotia?
microtia? macrotia? melotia? otoplasty? |
anotia: no pinna
microtia: small pinna macrotia: big pinna melotia: displaced pinna otoplasty: cosmetic surgery to pin back ears |
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what does congenital mean?
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present at birth
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Describe the external auditory meatus and its function?
what does it produce? |
to protect the tympanic membrane and keep it at a constant temperature and humidity. filter to reduce the lower frequencies, efficient transfer of energy to TM.
outer 2/3 is skin covered cartilage with hair follicles and sebaceous glands secrete sebum. sebum + air particles = cerumen (ear wax) osseocartilaginous junction is the divided protuberance between bone and cartilage. inner 1/3 is hairless with no glands |
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atresia?
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complete block of ear canal
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stenosis
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narrowing of the ear canal
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external OTitIS
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inflammation in the skin of outer ear (EAM)
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OToMYCOsIS:
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ot-: ear
myco: fungus sis: disease/inflammation fungal external ear infection |
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FFFFuronculosIS
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infection of the hair FFollicles
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NECROtizing
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cause bone destruction
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OSTEitIS
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bone inflammation of the EAM
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OSTEO-MYEL-lit-IS
osteomyellitis |
inflection of bone or bone marrow
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osteomas
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bony mass in EAM
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EXO-stoses and how is it caused?
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outward projection, caused by severe cold without a hat, swimming in cold water
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2 reasons why the ear canal would collapse
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Elderly: Ear canal sags because there aren't enough cells producing wax
lack of support because of earphones |
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Structures and 2 functions of the middle ear?
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mechanically carries acoustic energy from outer air to inner ear fluids and overcomes the impedence mismatch
tympanic membrane, ossicles, and eustachian tube, |
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describe the tympanic membrane?
what tissues does is consist of? what holds it in place? what does it do and how? what is the taut and loose part? |
-concave semi-transparent disk-like structure
-it has 3 layers: epidermal (outer), fibrous (middle) and the mucous -held in place by a ring of tissues= annulus -sound pressure waves cause vibrations and transfers to the ossicular chain by the fubrous tissues -taut: pars tensa and loose: pars flaccida |
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what are the ossicles and their functions?
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malleus (manubrium is the handle) > incus > stapes >oval window
malleus and incus act as a lever. the malleus moves with greater distance because it is longer so the incus needs to move with greater force because it is shorter and wider which brings more energy to the stapes then what the TM had originally. |
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what is the space around the ossicles and what does it do? what bone holds this space?
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middle ear space is filled with air in order to create pressure. the mastoid bone holds middle ear
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what is the eustachian tube and how does it work and consequences if it doesn't work? What closes and opens it?
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ET drains middle ear of infectious and normal fluid into the nasopharynx and maintains equalized pressure in ME or else TM could rupture. Tensor veli palantini muscle closes/opens it.
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eustachian tube in children
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the ET remains open until 6 months in children
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what happens to eustachian tube at extreme pressure?
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ET locks shut so pressure equalization is impossible and person is in great pain and at risk for a TM rupture and ME effusion (incoming fluid)
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what are the muscles in the Middle ear and what are they attached to? Why are they there?
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these muscles are attached to the ossicles
stapedius: tenses the oval window by tightening the stapes tensor tympani: tenses the tympanic membrane by moving the malleus - they tense the system in order for the acoustic reflex to occur |
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What is the acoustic reflex?
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AR occurs because the stapedius and the tensor tympani tighten the middle ear system. The AR protects against intense and low frequencies and kicks in at 80-90 db and takes off about 10-15 db. but only works for 10 seconds. It also enhances higher frequencies so that you can differentiate them in speech better
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What is the impedance mismatch?
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30 dB are lost due to the transfer of acoustic energy from the air to fluid boundary
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how does the ear fix the impedance mismatch? (3 ways) and by how much
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1) the way the ossicles form a lever produce more energy to the oval window. 1:1.3 (eveytime the TM moves 1 mm, the stapes moves 1.3mm)
2) size difference between the tympanic membrane and the oval window (17x bigger) 3) curved shape of the tympanic membrane puts more pressure on the malleus -all of these things, make back the 30 dB lost in the energy from air to liquid |
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what is negative pressure?
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less pressure in the space than outside (atmospheric pressure)
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what is tympanosclerosis, does it impact hearing?
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scar tissue on TM; thickening of the ear drum which makes it more flaccid. makes it more flaccid but does not impact hearing
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MYRINgitIS
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inflammation of TM (mirror)
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cholesteaTOMA
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benign mass
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PETROsitis
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infection of holy rock (mastoid)
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barotrauma and how does it happen?
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negative ear pressure in the middle ear space.if a diver goes up too fast then the ET doesn't have time to equalize the pressure so it shuts and creates a vacuum in the middle ear space. lots of pain,
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patulous eustachian tube, what does it feel like and who are at risk?
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chronically open ET. feels like your head is in a barrel, you can hear your own chewing and breathing. weight lifters and bulimics are at risk.
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OTO-SCLEROSIS, do they have a clarity problem?
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formation of new spongy growth that hardens over stapes and footplate, blueish cast over eyes, women are prone, amplitude problem not a clarity problem. they hear better in a noisy place because they can't hear the small noise, they only hear everyone talk really loudly
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why don't fish have a middle ear?
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fish don't have a middle ear because they are in water, don't need amplification or to compensate their impedance mismatch because there is no change in medium boundary (liquid > liquid)
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what is otitis media and what are the 3 general categories and explain?
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serous OM (or mucous OM): air in the space is replaced by any type of fluid other than pus (milk, snots, allergies, etc) no bacterial infection.
acute otitis media : middle ear is filled with bacteria, acute infection, fever, pain chronic otitis media: fluid of any kind remains for an extended period of time. serous >acute>chronic |
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what is serous otitis media and what does the tympanic membrane look like. what are the remedies?
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Serous Otitis Media is when the air in the middle ear is replaced by any fluid that is not puss (infected fluid). such as milk, snots, allergies, etc. when the eustachian tube isn't working properly. there might be no symptoms. The tympanic membrane is retracted because of the fluid in ME which pulls on the TM. Usually, SOM goes away by itself, antibiotics don't work since it's not an infection
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what is acute otitis media and what does the tympanic membrane look like. what are the remedies?
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Acute otitis media happens when the middle ear is filled up with bacteria, it is a viral infection. there is a rapid onset with fever, pain, etc. serous could have developed into acute otitis media. the tympanic membrane is angry, reddish, yellow, white and bulging outwards and shouldn't be confused with a screaming child's red TM
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what is chronic otitis media and what are the remedies?
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chronic otitis media is when the bacterial fluid in the middle ear keeps coming back for an extended period of time.
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how is a myringotomy done?
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scalpel slits TM and takes out the fluid. could also put tubes in which sustains the perforation to allow fluid to drain out. the tubes act like the ET so there's no build up of pressure
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what are the potential impacts of otitis media?
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lack of symmetrical hearing, can change how auditory pathways develops and audition is processed. speech perception problems because of absent and distorted speech signal, child might miss something like morpological markers (high frequency ---> directional and low intensity --->bend around), short words, inflection.
language development: not sure what is going on around them, miss important interactions in environment |
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What does tympanometry measure?
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tympanometry tells us about how much sound is passing through the middle ear and you infer compliance of middle ear (it is an indirect measure of the middle ear function,)
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why do we care about tympanometry? 3 reasons
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1) part of a complete test battery
2) issues with the middle ear are often treatable 3) consequences of temporary loss can impact social and professional work |
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what does immittance, admittance and impedance mean?
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Immittance: how easy a system can start (how easy does it vibrate)
admittance: once it vibrates, how easy can the information (energy) flow through impedance: the amount of resistance on a system |
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What are the factors that cause impedance? (3)
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1) resistance: determined by ligaments of the ossicles
2) stiffness: determined by pressure between stapes 3) mass: determined by weight of ossicles and tympanic membrane |
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what would disrupt middle ear functioning? (3)
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1) negative ME pressure (eustachian tube dysfunction)
2) increase in stiffness (otosclerosis or arthritis) 3) high admittance (displacement of ossicles due to head trauma) |
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how does the tympanometry work?
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eardrum vibrates most efficiently when the pressure is equal on both sides because energy flow is maximal.
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what are the steps in tympanometry?
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1) Measure the outer ear compliance (ECV): add positive pressure (+200daPa) to the outer ear so that the TM becomes very stiff (immobilized) so all the sound should bounce back. The ECV should be between .2-2cm3
2) Measure outer and middle ear compliance: keep changing the pressure and eventually you reach a point where the TM doesn't bounce sound back because at that point it is at it's most compliant 3) Subtract the outer ear from ME +OE--->(ME+OE)-OE = peak compliance (static compliance=middle ear value) .3-1.5 cc or cm3 |
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what are normal static compliance measurements for the middle ear? what does it mean if they are higher or lower?
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0.3 -1.5 cc or cm3
higher than normal: TM is flaccid lower than normal: TM is too stiff (impedance) |
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what does high compliance mean?
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minimal sound is bouncing back because the energy is transferring properly. the stiffer TM is, the more sound bounces back
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what does low compliance mean?
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a lot of sound is bouncing back. decreased energy flow.
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what does a Type A tympannogram look like? what is the point of greatest compliance and the peak at the maximum compliance? who has type A?
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-pressure of inner ear = pressure of outer ear which means that there is minimal to zero sound bouncing back.
-point of greatest compliance is ideally at 0 daPa (atomospheric pressure) -typically normal hearing people and people with hearing loss involving the inner ear only have a type A tympanogram |
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what does a Type A tympannogram look like? what is the point of greatest compliance and the peak at the maximum compliance? what does the ECV tell you? who has type A?
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Type B is flat, changing the pressure won't make a difference because either the air is going through TM or it's blocked somewhere therefore the pressure cannot be built up
-NO point of greatest compliance and no peak because there's a perforated TM or blocked canal or fluid in middle ear. Have to look at the ECV in order to tell what's wrong with the ear. if it's a high ECV, there's a hole (no matter how much positive pressure you put, the air will always escape). if it's a low ECV, then there is a blockage. normal ECV means that there is a problem with the Middle ear/fluid in ear (OME) People who have type B tympanograms have a hole in TM (high ECV), blockage (low ECV) or fluid (normal ECV) |
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what are the other kinds of Type A tympanograms can you get?
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Ashallow: the TM is very stiff, more than normal sound bouncing back so low compliance
Adeep: the TM is more flaccid (loose fibrous) so higher than normal compliance |
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in what situation does the acoustic reflex kick in? where is the acoustic reflex mediated?
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when there's a surge of sound bouncing back from the TM this means low compliance so the ear needs to protect itself (elicited with high intensity). This is when the stapedius and the tensor tympani kick in, and the AR is mediated at the superior olive (pons)
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what does the tympanograms be for 1) microtia 2) ME tumour 3) marble in EAM 4) scar tissue on TM 5) perforation
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1) type a 2) type b with normal ECV 3) type b with low ECV 4) Adeep scar tissue=flaccid=high compliance 5) type b with high ecv
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what are the structures of the inner ear. name in order of what the sound waves pass through from the stapes footplate to round window
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stapes footplate > oval window > vestibule > scala vestibuli > reissner's membrane > scala media > basilar membrane > scala tympani > round window
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what is the vestibule, what does it and what is it responsible for?
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the vestibule is the entrance after the oval window in the inner ear. it is responsible for equilibrium and houses the utricle and saccule (balance and rotational movement).
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what is inside the cohlea?
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scala vestibuli, reissner's membrane, scala media, basilar membrane, scala tympani, organ of corti, tectorial membrane
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what are the fluids that are contained in each chamber of the inner ear?
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scala vestibuli: perilymph
scala media: endolymph scala tympani: perilymph vestibule: perilymph utrICLE and sacCULE: endolymph *ICLE and CULE mean small in latin |
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Explain the organ of corti.
what is it? where is it located? what is inside of it? |
the organ of corti is the end organ of hearing (where hearing sensation is perceived)
it sits on the basilar membrane in the scala media (cochlear duct). It houses the outer hair cells (OHC), which is embedded into the tectorial membrane above and the inner hair cells (IHC) which is not embedded into the tectorial membrane. |
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how many hair cells do we have in the cochlea and where are they and what kind are they (afferent or efferent)?
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there are about 1200-1500 hair cells along the basilar membrane. OHC are arranged in 3 rows. they have efferent (motor) and the IHC are arranged in one single row. They are afferent (sensory)
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What is the traveling wave theory and how does it relate to the cochlear amplifier?
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The traveling wave theory explains the movement of the basilar membrane which is based on the movement of the stapes at the oval window. It relates to the cochlear amplifier because the basilar membrane needs to move in order to stimulate the Outer hair cells (traveling wave) and the outer hair cells need to move to bring the basilar membrane and the tectorial membrane closer together in order to stimulate the movement of the inner hair cells (cochlear amplifier) because the movement of the basilar membrane is not enough for the inner hair cells to stimulate the tectorial membrane and produce an electrical current.
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what is the cochlear amplifier? what does it NOT do?
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the cochlear amplifier does not amplify sound, it amplifies the movement of the outer hair cells in order to bring the basilar and the tectorial membrane together so that the inner hair cells shear and the sterocilia cells bend to touch the tectorial membrane in order to produce an electrical current
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what are the basilar membrane's responses to different frequencies? and what is this called?
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tonatopic organization:
-lower frequencies have smaller/shorter waves so they vibrate the basilar membrane closer to the base (nearer to the stapes) -higher frequencies have longer waves so they can reach the basilar membrane and vibrate closer to the apex. |
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what is the traveling wave theory?
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for each inward-outward movement of the footplate of the stapes, there is a downward-upward movement of the basilar membrane which is produced by the disturbance in the endolymph
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what happens if there is inner ear damage?
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it becomes a clarity problem because the IHC aren't as sharp as they used to be. in the case of a hearing loss, the OHC aren't notifying the IHC that theres sound.
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what is the propagation of sound?
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stapes movement > wave-like hydromechanical vibration of fluid enters the scala vestibuli which moves the reissner's membrane > distrbs the endolymph in the cochlear duct (scala media) -> endolymph moves the basilar membrane (due to traveling wave) -> outer hair cells move and stimulate the inner hair cells (cochlear amplifier)> electrical current!
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what structure of the ear matches conducting mechanism? sensory? neural?
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conducting: outer and middle ear (responsible for getting/conducting sound to the inner ear)
sensory: cochlea (sense organ) neural: nerve |
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what are the 5 different types of hearing loss? and where is hearing disrupted?
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conductive: disruptions in outer and or middle ear.
sensory: disruptions in cohlea neural: disruptions in the nerve (hard to distinguish between sensory and neural so usually just sensorineural) mixed: disrupted in either middle or outer and ALSO inner ear (conductive and sensorineural) cortical/central: disruption is beyond auditory nerve (only in brain) |
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what kind of hearing loss and tympanogram would a person have for;
-wax impaction? -hL from mumps -tonsils block ET causing ear pain -8th nerve tumour presbycusis + bug in EAM |
-conductive, type B (low ECV)
-sensorineural, type A -conductive, type C -sensorineural, type A -mixed, type B |
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what is the difference between acoustics and psychoacoustics?
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acoustics is the science of sounds and psychoacoustics is the study of the perceptual and/or psychological experience of sound "the act of hearing something"
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what are the two physical things we measure in a sound wave and what do they do?
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frequency: how fast an object is moving (measured in hertz)
intensity: how far is an object displaced (amplitude) (measured in decibel) |
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what is a decibel?
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decibel is measured on a relative scale, it needs to be referenced.
measures the smallest amount of pressure detected on the tmpanic membrane (1 unit) to the greatest amount of pressure before the tympanic membrane breaks (100,000,000,000,000 units) |
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what is the Bel?
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the bel is a logarithm of the ratio between two very big numbers. but still too big because a deciBel is 1/10 of a bel.
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what is dB SPL?
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dB sound pressure level is the objective measure on an acoustic level.
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dB HL? how did this measure come about?
0 dB HL = x dB SPL? |
dB Hearing level is the standardized acoustic level where perfect hearing is ideally 0 dB HL.
they conducted a study to see how many SPL's does it take for the average person to detect a sound at the lowest point. 0 dB HL = 7dB SPL |
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how do you convert from SPL to HL?
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Chart: pick the number that corresponds to the hertz level and subtract that number to the SPL to get HL.
HL -> SPL : add that number to HL |
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what is dB SL?
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dB SL is the auditory threshold of a specific individual. it's the number of decibels of a sound above the level where the person an just barely hear is their own personal sensation level.
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What is the normal hearing level for the average adult for all frequencies?
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-10 to +25 dB HL
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explain the weber tuning fork test. what does it test and why?
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the weber is a test of lateralization and bone conduction. you put the tuning fork on the forehead and the sound will lateralize to the blocked ear. in a typical hearing person, the sound will be heard in both ears.
-Because the conductive ear hears better with bone conduction since the sound bypasses the outer and middle ear. |
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what are the 5 purposes of a hearing screening?
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the purpose of a hearing test is to identify people with potential hearing problems, give out referrals, collect data, provide education and promote good hearing health.
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what does a hearing screening NOT do?
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a hearing screening does not identify the type of hearing loss nor does it identify the degree of the hearing loss.
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what is a false positive? false negative in a hearing screen?
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false positive: you said that there was a hearing problem when there really was not.
false negative: you said there was not a hearing problem when there really is on |
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what frequencies should you use for a hearing screening? which ones should you not hear? and at what dB?
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250 hz blends in with the hum of a room.
500 hz can be difficult to hear and might give you too many false positives. typically you use 1000, 2000, 4000 and most are done at 25 dB. |
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what does a hearing test test? and what does it NOT test?
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not actually testing their hearing but you are testing their response to the beeps that you hope correlate with their hearing.
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what is the aim of a hearing test?
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the aim of a hearing test is to determine the hearing sensitivity across the number of different frequencies.
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what are you trying to find in a hearing test?
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trying to fnd the sofest intensity a person responds to only 50% of the time (threshold) at each frequency.
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how do you hear with air conduction and bone conduction? which method does one hear better at?
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AC: the testing of air conduction measures the response of the entire system. OE>ME>IE>nerve>brain
BC bypasses the outer and middle ear, goes straight to IE>nerve>brain. it determines the sensorineural sensitivity. |
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why does the pure tone testing equipment need to be calibrated? at what calibration?
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0 dB HL AC = 0 dB HL BC.
The person hears both AC and BC at the same level. because we want the typically hearing person to hear the same by BC and AC. If they do have a conductive loss, they will hear better by BC than by AC at the same intensity. since we usually hear better by AC in the real world. |
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what are the symbols for AC unmasked and BC unmasked in the left and right ear?
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AC UM right: red circle; left: blue X
BC UM right: red < ; left blue > |
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what is the proper order when conducting a pure tone test?
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1) instructions
2) patient response 3) headphone placement 4) bone oscillator placement 5) skill with placement |
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what is the order of testing and which dB do you start at?
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1000 2000 4000 8000 1000 500 250
at whatever dB you want. usually start at 60 dB |
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when can AC be worst than BC?
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AC can be worst than BC when there is a conductive loss (problems in the outer and middle ear)
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how do you determine the threshold for a given frequency?
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the 50% threshold for a given frequency is when there are 3 positive answers and 2/3 are ascending.
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What are the limitations of the pure tone hearing test?
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1) 5 dB ascending steps are used and sometimes the person is hearing 100% of the time because their 50% is in between the steps.
2) test-retest reliability is +/-5dB which means that a 1 dB difference might not be significant. |
