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22 Cards in this Set
- Front
- Back
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According to Reavis et al., 2008,what was the criteria used the in the study to determine the a significant change in DPOAE level?
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Criteria for Significant Changes in DPOAE Level
• ≥ 4 dB level reduction or loss of response at two or more adjacent test frequencies • Reduction in level to below -10 dB SPL is considered to be a valid DPOAE change |
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What region of the cochlea does ototoxic insults damage initially?
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Base prior to Apex
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What are the three different DPOAE paradigms that can be used for monitoring purposes? Which paradigm(s) would you choose for monitoring and why?
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DPOAE frequency sweep, DPOAE level sweep, and DPOAE ratio sweep (group delay)
DP level or ratio sweep b/c earlier indicators of ototoxicity |
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Why would you choose to monitor DPOAEs versus behavorial thresholds when looking for signs of ototoxicity?
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Changes can occur earlier in DP’s vs. thresholds
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What was one of the conclusions drawn from the study by Dreisbach and Siegel (2001) and how is it related to monitoring using OAE.
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We are still in need to objectively test high-frequency hearing where damage can initially be detected, for those patients that are too sick or young to provide reliable behavioral responses. From the study, we know we can measure HF DPOAEs and its behavior is similar to LF DPOAEs. Therefore, HF DPOAEs would be an excellent objective measure for monitoring high frequency hearing where it is a common region for insults such as ototoxicity or noise exposure.
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What are the two recognized sources of OAEs?
a. The 8th nerve b. The overlap region and the characteristic frequency area c. Inner hair cells and outer hair cells |
b. The overlap region and the characteristic frequency area
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What is a unique characteristic of SFOAEs?
a. They are performed with only one level b. The response frequency is the same as the stimulus frequency c. They require less time to perform then the standard OAEs used clinically |
b. The response frequency is the same as the stimulus frequency
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What amount of suppression would you likely see with auditory neuropathy?
a. Complete suppression of the response b. Little to none c. 1-4 dB of suppression |
b. Little to none
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What are the two main techniques to separate OAE sources?
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Masking and calculations using the Inverse Fast Fourier Transform (IFFT)
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What structure is supposedly responsible for suppression in contralateral masking?
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The Olivocochlear relfex arc
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You are testing an infant for auditory neuropathy. At this point in your assessment, you have confirmed abnormal ABR pathology, and so far all OAEs have been absent as well. Using ECochG, how can you determine whether or not they have normal hair cell function (other than OAEs), whether or not they have auditory neuropathy, and how would you go about doing so?
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Use ECochG to see if they have a cochlear microphonic. If they do, this confirms normal outer hair cell function, which in conjunction with absent / abnml ABRs fits the diagnosis for auditory neuropathy.
To visualize the ECochG, run a rarefaction click stimulus and a condensating click stimulus separately. Use the computer ECochG program to subtract them from each other. R - C, thus combining the two traces via subtraction. The CM will appear as a large squiggly line with several positive and negative peaks appearing where the SP is normally visualized. correct drawings are also acceptable answers |
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match the stimulus type to the measure used for evaluating Meneire's Disease / Endolymphatic Hydrops
a. rarefacting and condensating click 1. SP magnitude b. tone burst 2. SP/AP ratio c. click 3. AP-N1 Latency Difference |
a - 3
b - 1 c - 2 |
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Other than SP/AP magnitude ratio and SP/AP area ratio, another method of evaluating Meneire's Disease / Endolymphatic hydrops was discussed that appeared clinically useful.
What is it, how is it measured, and what is the approximate criteria? (ignore the fact that clinic norms would need to be established, etc etc) |
Look at N1 latency. Compare the latency difference between a condensating click trace and a rarefacting trace. If the latency difference is greater than 0.38 ms, this is an indicator of endolymphatic hydrops.
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Name 4 clinical application of an ECochG within an audiologists scope of practice
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a) Evaluation of Meneire's Disease / Endolymphatic Hydrops (either gets full credit)
b) Identification of Wave I in ABR c) Intraoperative Monitoring - specific examples also get full credit: preservation of hearing identification of anatomic landmarks predicting post-op outcomes d) Help diagnosis of Auditory Neuropathy |
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A chinese patient has been referred to you as a rush audiology ENOG consult. The patient experienced the onset of Bells Palsy symptoms yesterday, saw the ENT today, and the ENT immediately sent him to you for an ENOG.
You have just finished running the ENOG on the patient. The involved side had an amplitude of 250 microvolts. The amplitude of the uninvolved (normal) side was 1000 microvolts. what is the percent degeneration? What is the patient's prognosis? What are the patient's next steps? |
percent degeneration = 100 - {(amp. paralyzed side / amp nml side) x 100}
250/1000 = 25% 25% x 100 = 25 100-25 = 75% degeneration (makes sense considering the paralyzed side has only 1/4 amplitude of the normal side) the patient's prognosis is too early to tell, ideally test after 3 days of onset of symptoms to allow for wallerian degeneration, but before 21 days. patient's next steps are to return to ENT for medical follow up and retesting in 3 days, every 3-5 days. |
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6. Under what conditions of hearing should contralateral masking be provided for EChoG?...and why?
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None
electrophysiology response from the NTE is is very small ECochG components are generated before (auditory) crossover |
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Draw the electrode montage for an ENOG test on one side of the face
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Latency***
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What are the drawbacks of MRI?
a. Limited availability b. High cost c. Uncomfortable for some patients d. All of the above |
d. All of the above
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What are the two advantages of Stacked ABR over conventional ABR testing?
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1) Better at detecting small tumors (<1 cm), 2) less people are incorrectly identified as having tumors
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Describe the measurement and analysis of SABR
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Clicks are presented in the presence of ipsilateral high-pass noise masking and the successive responses are subtracted to obtain frequency specific ABR responses. The derived bands from each frequency are stacked and the amplitude of Wave V of each of the responses are added together. If any abnormality exists the amplitude of the SABR will be reduced.
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CHAMP is used to test for
a. Small tumors <1 cm b. Semicircular canal dehysance c. Meniere’s disease d. Otosclerosis |
c. Meniere’s disease
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Interpret these CHAMP results. Which patient has Meniere’s disease? Why?
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Patient 2 has Ménière's disease. The latency delay between the click ABR and the click with 500 Hz high-pass masking ABR is less than 0.3 ms.
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