ABRS Exam Questions & Answers

ABRS Exam Questions & Answers Low frequency sounds are at - ✔✔the apex of the cochlea Wave III of the BAEP is generated by - ✔✔cochlear nucleus A rarefaction click occurs when the - ✔✔initial movement of a transducer ...

ABRS Exam Questions & Answers Low frequency sounds are at - ✔✔the apex of the cochlea Wave III of the BAEP is generated by - ✔✔cochlear nucleus A rarefaction click occurs when the - ✔✔initial movement of a transducer diaphragm is away from the tympanic membrane the masking level suggested for the elimination of crossover responses is - ✔✔60 dB SPL What problem may occur when performing intraoperative BAEPs using compressible tubing - ✔✔The tubing may become obstructed and obscure the sound to the ear An appropriate BAEP stimulation rate to avoid synchronization with 60Hz artifact would be - ✔✔9.5 per second When recording BAEPs in the OR, some auditory stimulators utilize several inches of tubing to connect the transducer and ear inserts which - ✔✔delays the arrival of the sound to the ear and separates stimulus artifact If the patient's threshold is 25dB and the stimulator is set at 85dB, then the intensity is - ✔✔60 dB SL Increases in latency of both right and left ABR wave V of 0.9msec in a 10 minute period would most likely indicate - ✔✔temperature effects ABR wave V will increase in latency about - ✔✔0.2ms per degree Centrigrade ABR waveforms cannot be recorded in all the following conditions except - ✔✔electrode montage FPZ-A (ipsi) Increasing the BAEP rep rate from 3.4 to 31.1 - ✔✔increased latency, decreased amplitude During BAEP from posterior fossa craniotomy, if reversible loss of all ipsi BAEP responses occurs - ✔✔complete recovery of neuronal function A stimulus rate that is suitable for ABR monitoring - ✔✔31.1 Hearing level is - ✔✔average threshold intensity of normally hearing young adults Which montage will help you discern waves IV and V in a BAEP - ✔✔CZ-contra ear If the ear canal is occulced, you may expect - ✔✔prolongation of all wave latencies The sound stimulus intensity at the tympanic membrane depends on the - ✔✔acoustic coupling between the sound stimulus generator and the ear Generally speaking, rate increases above 30 per second in BAEP studies - ✔✔will increase the latency and decrease the amplitude of the BAEP To optimally monitor cranial nerve VIII function in the operating room, it is desirable to be able to simultaneously perform - ✔✔BAEPs and electrocochelograms (ECochG) The BAEP measurement of III-V interpeak intervals represents - ✔✔conduction through the upper brainstem It is recommended while recording intraoperative BAEPs, the recording electrodes be sealed with tape in order to - ✔✔prevent drying and protect from fluids the term "broadband click" refers to - ✔✔peak acoustic power of 2-4kHz A recommendation to minimize stimulus artifact while recording BAEPs intraoperatively is to - ✔✔use alternating clicks A condensation click - ✔✔causes the headphone diaphragm to displace toward the tympanic membrane The recommended criteria for surgeon notification when monitoring BAEPs intraoperatively includes - ✔✔an increase in the latency of wave V of 1.0msec or greater or the disappearance of wave V What is the most important step to setting up ABRs - ✔✔placing the foam inserts If you have a lot of high frequency noise in your BAEPs you can - ✔✔change your filter from 2500 to 1500Hz If a sound intensity is increased from 20dB to 40dB then the sound pressure has increased by a factor of - ✔✔10 Loss of BAEPs during drilling of the internal auditory canal is likely due to - ✔✔excessive noise In ABR stimulation, the stimulus type which causes a negative pressure resulting in slightly earlier latency - ✔✔rarefaction What is the most common reason for loss of BAEPs during retromastoid microvascular decompression? - ✔✔Compromise vascular supply You would expect a loss of BAEPs in which surgery? - ✔✔Pontine glioma Reversible loss of ABRs indicate - ✔✔complete neurological recovery The appropriate analysis time for ABRs is - ✔✔15mS Which of the following would enhance wave I of the BAEP? - ✔✔increase in intensity In BAEPs, wave I can most easily be differentiated from cochlear microphonics based upon - ✔✔click polarity What is the interstimulus interval of a 50Hz click stimulus - ✔✔20.00msec Contralateral masking should be used during BAEPs to - ✔✔prevent crossover responses The complete absence of a BAEP is most likely the result of - ✔✔severe hearing loss Identification of wave V of the BAEP may require - ✔✔decreasing stimulus intensity During posterior fossa surgery, when BAEPs are used for monitoring brainstem function, it is most important to - ✔✔Stimulate and record from the contralateral side In recording electrocochleograms, it is best to stimulate using - ✔✔alternating clicks during posterior fossa surgery, wave V of the BAEPs may increase in latency due to - ✔✔retraction of the cerebellum The pneumatic drill has which of the following effects on BAEPs - ✔✔prolongs wave V which of the following would most affect the ability to record BAEPs - ✔✔coagulator Which of the following most often causes a temporary threshold shift on the BAEPs during CPA surgery - ✔✔drilling Which of the following measurement would be most helpful during monitoring of endolymphatic sac surgery - ✔✔summating potential/AP amplitude ratio What is the suggested intraoperative auditory stimulation according to ACNS guidelines - ✔✔100dB pe SPL with masking Which is an advantage of using alternating click polarities - ✔✔decreased stimulus artifact For ECochG recordings, it is best to stimulate using - ✔✔alternating clicks What is the average number of trials for BAEPs - ✔✔>1000 Which of the following is an appropriate bandpass for BAEPs - ✔✔10-2500Hz What sweep is appropriate for BAEPs - ✔✔15mS When setting up for BAEP monitoring, what is most critical? - ✔✔using foam insert What is the most acceptable interperiod sample to resolve ABR waveforms - ✔✔0.02mS the most appropriate ABR interstimulus interval is - ✔✔20mS you would expect a loss of ABRs in which surgery - ✔✔pontine glioma If you have attenuation of wave V of BAERs that persists until closing, what is the most likely cause - ✔✔retraction of the cerebellum When opening posterior fossa, what is the most likely cause for the attenuation of wave I for BAERs - ✔✔drilling cranium