Term
ABR Protocol:
-Start out with ___. Present at ____ dB nHL.
-If it shows normal latencies switch to ___ ABR.
-Start at ___ Hz toneburst
-Estimate ___ |
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Definition
| clicks; 70-90; toneburst; 500; thresholds |
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Term
| How do you estimate thresholds with TBs? |
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Definition
| Find a reliable wave five at lowest intensity. Then do formula: intensity level minus CF. CF: 500 Hz=15-20 dB and 1, 2, and 4 kHz=10-15 dB |
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Term
What are the stimulus parameters for clicks?
List duration, transducer, polarity, rate, intensity, repetitions, masking, and mode. |
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Definition
| .1 ms; insert or supra-aural headphones, rarefaction, 22.1 or 27.3 cycles per second; masking if wave 1 is absent during ipsi recording; mode is monoaural. |
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Term
| How does wave morphology change for low frequency ABR tone burst? |
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Definition
| Wave 1 may be absent, latency is longer with lower frequency, and wave five may be more rounded with lower frequency and intensity. |
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Term
| Acquisition parameters for BC ABR including transducer, electrodes, polarity, click rate, filters, and sweeps. |
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Definition
| Bone oscilator; inverting electrodes on earlobes (exclude mastoid placement); alternate polarity; slow down click rate to 11.1 or 21.1; set high pass filter low at 30, 75, or 100 Hz; increase number of sweeps |
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Term
Interpreting ABR:
1. When click-evoked ABR shows delayed wave 1 latency at high intensity
2. If click-evoked ABR is normal at high intensity, but abnormal or absent at low intensity
3. If click-evoked ABR is abnormal or absent at high intensity
4. If there is no clear click-evoked ABR at high intensity |
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Definition
1. Consider CHL. Do BC ABR. Measure Tymps. Refer to ORL
2. Suspect mild/moderate SNHL. Estimate thresholds with TB. Verify sensory auditory dysfunction with OAEs.
3. Suspect severe SNHL. Record ABR at max intensity level. Consider conducting ASSR.
4. Suspect AN/AD. Record ABR with rarefaction and condensation. Look for CM. |
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Term
-A cochlear microphonic is generated by the ____. It is an ___ voltage that mirrors the __________. Can be hard to separate from ___. Is helpful in diagnosis ____.
-Summating Potential is generated by the ___. A ___ voltage that shows ___ ___ pattern of the cochlea in response to the stimulus. Can be hidden by ___ ___ or ___ ___.
-Action Potential is generated by the ___ auditory nerve fibers. Produces AC potential that represents the summed response of ___ neural firing. |
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Definition
| OHC; AC; wave form of the stimulus; artifact; AN; IHC; DC; time displacement; CM; stimulus artifact; distal; synchronous |
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Term
| Who discovered ECochG and when? |
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Definition
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Term
| What are some clinical applications of ECochG? |
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Definition
| Diagnosing meniere's and AN |
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Term
Normal ECochG:
-CM ___ stimulus in time
-ABR looks the same regardless of which ___ is being used
-The CM changes polarity when the ___ polarity is changed-this confirms that CM is ___ |
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Definition
| follows; polarity; stimulus; present |
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Term
| When is horizontal montage used and what does it consist of? |
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Definition
-Single channel ECochG with TIPtrode
-Stimulus ear: inverting electrode
-Opposite ear: noninverting electrode
-Forehead: ground electrode |
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Term
| What are the stimulus parameters of ECochG? Including transducer, intensity, type, duration, rate, polarity, and masking. |
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Definition
| inserts; 70-90 dB nHL; clicks, .1 ms; 7.1 cycles/sec or slower; use alternating polarity to get SP (cancels CM). Do polarity one at a time for CM. Masking is never needed. |
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