Quiz 1 Answers Flashcards
(21 cards)
What are AEPs? What is one clinical application of them?
Auditory evoked potentials (AEPs), or evoked responses (AERs), measure the electrophysiologic responses of the auditory nervous system to a variety of stimuli. Neural activity in response to auditory sensory stimulation can be extracted from the EEG and viewed as a response. Clinical Applications include Newborn hearing screening/diagnostics, NOHL, confirmation of behavioral tests, difficult-to-test patients, etc.
What are amplifiers? What is the role of CMR in amplifiers?
An amplifier increases the strength of an electrical or acoustical signal. Amplification is crucial to measuring auditory evoked responses because AERs generated by the CANS are very small in amplitude compared to the EEG. Common Mode Rejection (CMR) is a vital amplifier function. The CMR allows the electrodes to pick up what is common to each electrode (noise) and cancel it out while retaining the evoked responses at the two electrode sites, because they are different
Which of the following filters should generally be avoided in recording auditory evoked responses?
Low Pass Filter
High Pass Filter
Notch Filter
Band Pass Filter
e. All the above filters can be used
notch
Audi Bel, a recent AuD graduate, is getting ready to perform an ABR on an adult. She is receiving an OPEN message when measuring electrode impedances. What is her MOST likely error?
Using silver chloride coated disc electrodes at Fz and A1 and a disposable electrode at Fpz
Using supra-aural earphones
Conducting the test using a grounded electrical outlet to reduce artifacts
Using a bandpass filter
Selecting a two-channel recording option for a one-channel recording montage
Selecting a two-channel recording option for a one-channel recording montage
The best assessment technique to diagnose auditory neuropathy spectrum disorder is?
Somatosensory evoked responses
Cortical evoked responses
Auditory brainstem responses
Magnetic resonance imaging
Visual evoked responses
abr
Regarding electrode impedances, which of the following is INCORRECT? (Check all that apply):
Low inter-electrode impedance is important for the common mode rejection (CMR) to work well
Under some circumstances, a reasonable electrode impedance even if > 5 kOhms in conjunction with low interelectrode impedances, can result in good AERs recordings
An impedance of 0 kOhms is most desirable for the best evoked potential responses
Low and balanced electrode impedances limit external and internal noise (interference)
An impedance of 0 kOhms may reflect a direct connection between two closely spaced electrodes resulting in superior AER recordings
An impedance of 0 kOhms is most desirable for the best evoked potential responses
An impedance of 0 kOhms may reflect a direct connection between two closely spaced electrodes resulting in superior AER recordings
What is the term for the technique used in obtaining an adequate signal-to-noise ratio (SNR) in AER recordings?
Notch filtering
De-amplification
Artifact enhancement
Common mode detection
Signal averaging
Signal averaging
What information is critical for filter settings used in recording AERs?
Frequency of the stimulus
Amplitude of the stimulus
Stimulus rate
Sleep state of the patient
Age of the patient
Frequency of the stimulus
The auditory evoked response is better at assessing _______________ of the auditory system and the MRI is better at assessing structural problems within the system.
function
________________ are generated by stimulation of afferent peripheral nerve fibers (e.g., Median nerve) by either physiological or electrical means and are used in intraoperative monitoring.
Somatosensory evoked responses (SERs)
A _______________ electrode does not undergo polarity reversal; it is simply amplified.
non inverting
Inter-electrode impedances should be balanced at about _________________ kOhms.
2
Or 2-3
A ground electrode placed low such as on the shoulder of a baby may record an _________________ response instead of an AER.
EKG
Or heart rate or heart beat
Auditory evoked potentials can be recorded from which of the following? Select the best answer.
The vestibulo-cochlear nerve (CN VIII)
The brainstem
The ear (cochlea)
The cerebral cortex
All of the above
all
Evoked potentials recorded by electrodes close to the potential field or where the potential is generated are called _______ responses whereas those recorded by electrodes at a distance from where the potential is generated are called _______ responses.
Responses recorded from electrodes placed on the scalp are considered ______ responses whereas those recorded from intratympanic needle electrodes or on the promontory of the cochlea would be considered _____ responses.
Near field, far field, far field, near field
Which of the following regarding exogenous and endogenous responses are TRUE. Select TWO answers.
Endogenous potentials are influenced by cognitive processing whereas exogenous are more related to the physical characteristics of the evoking stimulus
Endogenous responses do not require conscious “hearing” of the evoking stimulus and can be recorded on individuals who are asleep, sedated or unconscious
Exogenous responses require special participation from the patient such as reading a book, watching a movie or counting stimuli
ABR, OAE and ECochG are examples of endogenous potentials
ABR, OAE and ECochG are examples of exogenous potentials
Endogenous potentials are influenced by cognitive processing whereas exogenous are more related to the physical characteristics of the evoking stimulus
ABR, OAE and ECochG are examples of exogenous potentials
Based upon the concept of near-field vs far-field responses, for which of the following ABR setups would you expect to obtain the best (largest amplitude, most detail) response?
Inverting electrodes placed on the scalp
Inverting electrodes placed on the earlobes
Inverting electrodes placed against the tympanic membrane (TM-trode or tymptrodes)
Inverting electrodes placed on the mastoids
Inverting electrodes placed anterior to the tragus
Inverting electrodes placed against the tympanic membrane (TM-trode or tymptrodes)
Which of the following is NOT true regarding latency?
Latency is dependent upon a number of factors including stimulus type and polarity
Latency can be defined by the time it took for a specific wave or landmark to occur after stimulus onset (absolute latency) or the time interval from previous landmark (interpeak/interwave latency)
Latency is typically described in milliseconds
Latency is unaffected by age with most AERs occurring at the same time interval across the lifespan (from newborns to elderly)
For most AERs, latency tends to increase as you decrease intensity
Latency is unaffected by age with most AERs occurring at the same time interval across the lifespan (from newborns to elderly)
Which of the following is an example of a Non-Evoked or Non-Event related potential?
Auditory Middle Late Response (AMLR)
Neurologic Auditory Brainstem Response (ABR)
Threshold Auditory Brainstem Response (ABR)
Electrocochleography (ECochG)
Electroencephalography (EEG)
Electroencephalography (EEG)
EEG is an obligatory potential. All of the others require some kind of acoustic stimulus to elicit the response.
Which of the following is FALSE regarding AERs?
AERs are all separate and distinct potentials without any anatomical or waveform overlap.
When recording AERs, amplitude or peak voltage is typically displayed on the y-axis
When recording AERs, latency is typically displayed on the x-axis
Early AERs typically mature or reach adult configuration faster than late or cortical potentials
In AERs, latency is typically denoted by msec and amplitude in microvolts
AERs are all separate and distinct potentials without any anatomical or waveform overlap.
What is an Epoch and why is it an important consideration when recording AERs?
An Epoch is a length of time (in msec) relative to a specific auditory event. If you choose an Epoch that is too short, you may not see your entire response. If you choose an Epoch that is too long your response may get lost in the bigger display with limited detail. You want to choose the best time frame for the potential of interest.
