BAEP STUDY GUIDE
SAEP - Answers :-Short latency auditory evoked potentials
-electrical responses of the auditory pathways that occur withing 10-15ms of an
appropriate acoustic stimulus in normal subjects
-this term encompasses two categories of events: the "electrocochleaogram" and the
"BAEPs"
BAER - Answers :-Brainstem Auditory Evoked Responses
- Responses of the auditory nerve, brainstem and higher subcortical structures to
acoustic stimulation
ABR - Answers :Auditory Brainstem Responses
AEP - Answers :Auditory Evoked Potentials
Electrocochleography (ECochG) - Answers :- Recording of JUST wave I
- assesses function of ONLY Cochlea and includes three components:
1. the cochlear microphones
2. summating potentials
3. the auditory nerve compound action potential
What is the analysis time for ECochG? - Answers :5msec
What is the Cochlear Microphonic Generator? - Answers :outer hair cells in organ of
corti (Cochlea)
In the OR, what is the click polarity of choice for ECochG and why? - Answers
:Alternating Click Polarity becuase it cancels cochlear microphonics and artifact stimuls
and improves the identification of Wave I
Wave I can be differentiated from choclear microphonics based on what? - Answers
:click polarity
Rarefraction Clicks - Answers :-Goes in one direction with negative clicks
- Negative pressure on the earspeaker diaphragm
- Pulls AWAY from the tympanic membrane
- Best Wave I amplitude
Condensation Click - Answers :- Goes the OPPOSITE direction with positive clicks
- Positive pressure on the earspeaker diaphragm
- Pushes toward the tympanic membrane
- Best Wave V amplitude
Alternating Click - Answers :- Negative AND Positive pressure on the earspeaker
diaphragm
, - Cancels cochlear microphonic
- Cancels stim artifact
- Intraoperative monitoring
BAEP - Answers :-Brainstem Auditory Evoked Potentials
- resonses of the auditory nerve, brainstem and higher subcortical structions to acoustic
stimulation
Electrodes used for BAEPs - Answers :- Disc EEG electrodes applied with collodion and
sealed with plastic tape or sheet to prevent drying and providing protection from blood
or other fluids
-Bone wax secures the earphones. It does NOT protect the canal from fluid entry
- subdermal needle elecrodes similarly secured
In ordinary recordings between vertex and earlobe or mastoid electrodes, what should
the "vertex-negative" components of BAEPs which follow each vertex-positive wave be
labeled or designated? - Answers :I' through VI'
What is the recommended stimulus for BAEPs? - Answers :"broad-band" clicks which is
the acoustic energy of which is spread over a wide range of audio frequencies
How should broad-band clicks be generated? - Answers :by driving with a 100 usec
rectangular pulse (single monophasic square wave) and by a a standard audiometric
earspeaker having a relative flat frequency spectrum or through ear insertions for IOM
cases
At what stimulus rate do waves I, III, VI, and VII become particularly reduced in
amplitude? What stimulus rates are best suited to resolve these peaks? - Answers :- at
rates higher than 10/s
-rates of 8 - 10/s
What is recommended for the contralateral ear (nonstimulated ear) in order to eliminate
crossover responses? - Answers :That the contralateral ear be masked by white noise
at 60dB SPL
Recommended system bandpass for BAPEs? - Answers :10-30 to 2,500-3,000 Hz (-
3dB) and 60 cycle filter (Notch) off
Filter Rolloff for BAEPs? - Answers :- 12 dB/octave for low frequencies
- 24 dB/octave for the high frequencies
- A high frequency cutoff of 1,500 Hz is acceptable for intraoperative BAEPs
What is the recommended analysis time from stimulus onset? - Answers :10-15ms
What analysis time is essential for neonatal, pathology and intraoperative BAEP
recordings and why? - Answers :15ms because Lower temperature in the operating
SAEP - Answers :-Short latency auditory evoked potentials
-electrical responses of the auditory pathways that occur withing 10-15ms of an
appropriate acoustic stimulus in normal subjects
-this term encompasses two categories of events: the "electrocochleaogram" and the
"BAEPs"
BAER - Answers :-Brainstem Auditory Evoked Responses
- Responses of the auditory nerve, brainstem and higher subcortical structures to
acoustic stimulation
ABR - Answers :Auditory Brainstem Responses
AEP - Answers :Auditory Evoked Potentials
Electrocochleography (ECochG) - Answers :- Recording of JUST wave I
- assesses function of ONLY Cochlea and includes three components:
1. the cochlear microphones
2. summating potentials
3. the auditory nerve compound action potential
What is the analysis time for ECochG? - Answers :5msec
What is the Cochlear Microphonic Generator? - Answers :outer hair cells in organ of
corti (Cochlea)
In the OR, what is the click polarity of choice for ECochG and why? - Answers
:Alternating Click Polarity becuase it cancels cochlear microphonics and artifact stimuls
and improves the identification of Wave I
Wave I can be differentiated from choclear microphonics based on what? - Answers
:click polarity
Rarefraction Clicks - Answers :-Goes in one direction with negative clicks
- Negative pressure on the earspeaker diaphragm
- Pulls AWAY from the tympanic membrane
- Best Wave I amplitude
Condensation Click - Answers :- Goes the OPPOSITE direction with positive clicks
- Positive pressure on the earspeaker diaphragm
- Pushes toward the tympanic membrane
- Best Wave V amplitude
Alternating Click - Answers :- Negative AND Positive pressure on the earspeaker
diaphragm
, - Cancels cochlear microphonic
- Cancels stim artifact
- Intraoperative monitoring
BAEP - Answers :-Brainstem Auditory Evoked Potentials
- resonses of the auditory nerve, brainstem and higher subcortical structions to acoustic
stimulation
Electrodes used for BAEPs - Answers :- Disc EEG electrodes applied with collodion and
sealed with plastic tape or sheet to prevent drying and providing protection from blood
or other fluids
-Bone wax secures the earphones. It does NOT protect the canal from fluid entry
- subdermal needle elecrodes similarly secured
In ordinary recordings between vertex and earlobe or mastoid electrodes, what should
the "vertex-negative" components of BAEPs which follow each vertex-positive wave be
labeled or designated? - Answers :I' through VI'
What is the recommended stimulus for BAEPs? - Answers :"broad-band" clicks which is
the acoustic energy of which is spread over a wide range of audio frequencies
How should broad-band clicks be generated? - Answers :by driving with a 100 usec
rectangular pulse (single monophasic square wave) and by a a standard audiometric
earspeaker having a relative flat frequency spectrum or through ear insertions for IOM
cases
At what stimulus rate do waves I, III, VI, and VII become particularly reduced in
amplitude? What stimulus rates are best suited to resolve these peaks? - Answers :- at
rates higher than 10/s
-rates of 8 - 10/s
What is recommended for the contralateral ear (nonstimulated ear) in order to eliminate
crossover responses? - Answers :That the contralateral ear be masked by white noise
at 60dB SPL
Recommended system bandpass for BAPEs? - Answers :10-30 to 2,500-3,000 Hz (-
3dB) and 60 cycle filter (Notch) off
Filter Rolloff for BAEPs? - Answers :- 12 dB/octave for low frequencies
- 24 dB/octave for the high frequencies
- A high frequency cutoff of 1,500 Hz is acceptable for intraoperative BAEPs
What is the recommended analysis time from stimulus onset? - Answers :10-15ms
What analysis time is essential for neonatal, pathology and intraoperative BAEP
recordings and why? - Answers :15ms because Lower temperature in the operating
