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66 Cards in this Set
- Front
- Back
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What is the impedance mismatch between air and bone? |
50 dB |
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What is the impedance mismatch between air and cochlear fluids? |
30 dB |
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Air-conducted sound must exceed ________ threshold by at least ________ before __________ threshold reached |
1. Air Conduction 2. 50 dB 3. Bone Conduction |
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A sound of 80 dB by air conduction will transmit how much by bone? |
30 dB |
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Tonndorf distortional theory |
*Mechanism of BC is distortional vibrations of cochlea *Volume of SV > volume of ST *Distortions cause displacements of BM |
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Skull vibration causes... |
Ossicular vibration |
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What is the primary mechanism when testing by Bone Conduction: what are you testing? |
You bypass the middle ear and test the cochlea directly |
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Where are the two places you might place the bone osilator? Which is more common? |
1. On the mastoid 2. On the front of the head The mastoid placement is most common |
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Do the ossicles move side-to-side or front-to-back? |
side-to-side |
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Outer ear component of BC |
*source is cartilaginous portion of EAM *EC wall vibration -------- sound in EC space *Occlusion effect to be considered with ear canal of hearing aid/mold *Occlusion effect, a LF phenomenon **30 dB @ 250 Hz **20 dB @ 500 Hz **10 dB @ 1000 Hz |
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The occlusion effect, HF or LF phenomenon? |
LF |
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Besides through air, what causes the ossicular vibration? |
Vibration of the skull, in other words bone conduction |
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When will the sound energy be greater, with the ears covered or uncovered? |
When the ears are covered |
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Acoustic-Reflex contraction (attenuation levels by frequency) Which muscle is responsible for these levels? |
15-20 dB @ 250 Hz 10-15 dB @ 500 Hz 5-10 dB @ 1000 Hz 0-5 dB @ 2000 Hz **The stapedial muscle is responsible because the tensor tympani contracts for much higher thresholds |
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What could be the primary reason the noise induced hearing loss is HF? |
The acoustic reflex attenuation primarily attenuates the low frequencies but not the high frequencies; therefore, they protect the lower end of the frequency spectrum more over the high end. |
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What happens during the TT contraction? |
** Manubrium is pulled inward ** TM displaced inward |
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What happens during stapedius contraction? |
1. Contraction of this muscle pulls stapes perpendicular to piston-like motion so it rotates around its posterior ligament (does not cause movement of TM) 2. A "decoupling" between middle ear & cochlear fluid occurs |
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Tympanosclerosis |
Plaques develop on the TM *Calcium & phosphate crystals* Usually confined to the pars tensa Appears as white patches Associated with TM perforation or ME disease |
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myringosclerosis |
When confined to TM; not clinically significant |
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When tympanosclerosis appears in ME... |
fixes ossicles &obliterates ME cleft, leading to CNHL |
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When is tympanosclerosis usually identified? |
Usually not until exploratory surgery |
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Treatment for tympanosclerosis? |
Surgical removal of disease |
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Serous otitis media |
*Absorption ME nitrogen --- negative ME pressure *Negative ME pressure pulls fluid from ME mucosa *90% of cases resolve within 90 days *air/bone gaps, can have CNHL up to 50 dB |
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Language re: Otitis media |
Studies currently say no effect on language |
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Antibiotics and otitis media |
No-efficacious |
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Politzer maneuver |
This is a procedure to relieve ME pressure where you inject air (using air bag) through nostrils and swallow BUT is uncontrolled |
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EarClear (Silman & Arick) |
Same idea as Politzer maneuver but uses a controlled amount of pressure |
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Retraction pocket |
*Retraction pocket is localized area of AT of the TM *AT may be present prior to, concurrent with, or after OME If persistent or progressive, can lead to CH (cholesteatoma) and ossicular chain discontinuity |
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Atelectasis |
Severe retraction |
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Keratin |
Protein in cells |
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Cholesteatoma |
*Cyst lined by epithelium and keratin *Expanding, destructive bone lesion in ME *Can be congenital, but uncommon *can eat through the bone of ME ***ENT may have to remove ossicles to remove tumor |
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Primary acquired cholesteatoma |
Progressive retraction of TM Most commonly in pars flaccida |
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Secondary acquired cholesteatoma |
*Consequence of TM perforation, trauma, and surgery *Epithelium migrates inward, more commonly with marginal than central perforations |
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Early CH is ? |
Asymptomatic - neither causing nor exhibiting symptoms of disease |
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Later, CH... |
CNHL develops due to erosion of ossicular chain or mass effect of CH *Perforation frequently occurs, leading to worsening of HL & purulent otorrhea *treatment? -- surgical |
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purulent otorrhea |
foul, smelling discharge |
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TM perforation causes... |
*Blunt or penetrating head trauma *chemical or thermal injury *compression trauma from acoustic or *barometric injury *acute otits media *Cholesteatoma *tympanostomy tubes *CNHL |
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Acute otitis media define |
Inflammatory process of ME with CNHL |
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Acute otitis media etiology, signs |
Etiology is ETD Signs: **MEE **ME pain **otorrhea **fever **recent onset of irritability, anorexia, vomiting, or diarrhea **rapid onset of symptoms |
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Which type of otitis media needs treatment with antibiotics? |
Acute otitis media needs this treatment |
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Glomus Tumors types |
Glomus tympanicum tumors Glomus Jugulare tumors |
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Glomus body... |
is on the jugular bulb is also a chemoreceptor |
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Where do Glomus Tympanicum tumors arise from? |
The glomus body on promontory in ME |
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Where do Glomus Jugulare tumore arise from? |
Arise from Glomus body on Jugular bulb |
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The etiology of Glomus tumors? |
Is not well understood; obscure |
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Are Glomus fast or slow growing; expansive or localized? |
Slow; expansive |
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What are the initial complaints when someone for those who have had a Glomus tumor? |
**pulsatile tinnitus **Aural fullness **CNHL |
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For the Glomus Jugulare, what is another symptom that is not an auditory symptom? |
Lower cranial nerve injury such as hoarseness or aspiration These symptoms precede, come before the auditory symtoms |
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Treatment for Glomus tumors? |
Surgery and/or radiation |
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Otosclerosis define |
Stiffening of the three little bones; excess bone growth occurs at stapes footplate |
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Otosclerosis characteristics |
Charhart notch -- reflects loss of ossicular resonance *Genetically transmitted as auosomal-dominant trait with incomplete penetrance *80-90% of cases bilateral |
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In 90% of the otosclerosis cases, the disease is _______ to the footplate |
anterior |
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Disease progression: otosclerosis |
Stapes footplate fixation & CNHL |
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Treatment for otosclerosis |
BY surgery or amplifcation |
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Stapedectomy |
*Anterior crurotomy + vertical fracture of footplate *prosthesis |
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Stapedotomy -- |
**Crura + head removed **fenestration in footplate **prosthesis |
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Stapedotomy -- placement of prosthesis |
The placement is within opening of oval window attached to inucs bone
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Do AC & BC initiate same traveling waves in cochlea? |
YES |
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What did Bekesy show regarding AC & BC signals? |
He showed that the signals cancel when phases & amplitude adjusted; IE: 180 degrees out of phase |
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What did Lowy show? |
He showed that cancellation occurs in cochlea because CM cancelled |
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What is the CM |
It is electrical potential that reflects BM activity |
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Why can AC and BC thresholds be compared? |
Because of the phase relationship and the CM relationship |
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Regarding Bekesy and BC and skull vibration: state the frequency relationships |
@ < 200 Hz, the skull vibrates as a unit @ ~ 800 Hz, vibration of skull in 2 segments (F/B) @ > 1000 Hz, vibration of skull in 4 segments (f/b and sides) |
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Bekesy: When RW compliance = OW compliance... Cochlear fluids... |
Cochlear fluids non-compressible; equal bulging at OW & RW |
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Bekesy: When RW compliance > OW compliance... |
BM displaced downwards |
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BM displaced to greater degree than "B" indicates because area of ____________ and __________> area of___________ pressure release through cochlear aqueduct |
1. Vestibule 2. SV 3. ST |
