BAEP QUESTIONS AND ANSWERS
W1 - Answers :Distal VIIIth nerve
WIII - Answers :Pons - Superior olivary complex
WV Midbrain - Answers :Lateral lemniscus terminating in the inferior colliculus
Wave I appearing in contralateral ear recording is - Answers :failure of white noise
masking
Intensity of white noise masking should be - Answers :60 dB SPL
Failure to use white noise masking can produce a - Answers :false negative
CNIM Present ipsilateral response and absent contralateral response can only be
caused by one thing. - Answers :FLUID IN THE HEADBOX/JACKBOX
Most important preparation step in setting up IONM for Vestibular Schwannoma is -
Answers :WATER TIGHT SEAL with tape over ear
Middle Ear Infection is called - Answers :Otitis Media
Causes delayed absolute latencies
Otitis media causes dampening of amplifying effect
Ossicles job is to amplify sound by factor of - Answers :22
Age related HF hearing loss is called - Answers :presbycusis
Ischemia of Cochlea - Answers :Caused by trauma to internal auditory artery
Increase in absolute latencies
hypothermia below 19-20C - Answers :Increase in all interpeak latencies: I-III, III-V, I-V
Global slowing of conduction velocity
Cochlear nucleus lesion - Answers :Increased III-V, I-V
Neurofibromatosis Type II - Answers :Same as vestibular schwannoma
Increased I-III, I-V
Acoustic neuroma, Vestibular schwannoma - Answers :Increased I-III, increased I-V
Pontine Glioma or Midbrain infarction - Answers :Increased III-V, I-V
, Middle Cerebral Artery Infarction affecting Temporal Lobe - Answers :Normal BAEP
Pneumatic Drill & BAEPs - Answers :Prolongued wave V
CNIM will ask is: What type of artifact does the pneumatic drill produce. - Answers
:NONE
What instrument is known to cause a temporary shift in the BAEP? - Answers :The drill
Vestibular Schwannoma - Answers :Slow growing tumors in the cerebellopontine angle
which arise from the Schwann cells covering the vestibular portion of the VIIIth nerve,
hence the name.
Signs and symptoms:
Vertigo/balance disturbance
Hearing loss
Ringing in ear
Suboccipital Approach: Cerebellar retraction causes - Answers :increased wave V
latency (ON EVERY EXAM) and could lead to hearing loss if excessive and persistent
Occlusion of AICA - Answers :which is the parent vessel of the labyrinthine artery
causes infarct of the inner ear (cochlea)
Middle Fossa Approach - Answers :Advantages
Easy access to intracanalicular tumors, especially at the lateral end of the IAC
Hearing preservation in possible
Extradural, therefore low risk of CSF leak
Cochlear Microphonic (CM): Generator of CM is the outer hair cells in the organ of -
Answers :Corti
Alternating clicks used in surgery but NOT with - Answers :EcochG
Electrocochleography
Polarity of the CM waveform is tied to the polarity of the click- DO NOT use alternating
clicks here
Rarefaction - Answers :Negative pressure
Transducer diaphragm moves away from tympanic membrane
Emphasizes wave I amplitude and decreases latency
Condensation - Answers :Positive pressure
W1 - Answers :Distal VIIIth nerve
WIII - Answers :Pons - Superior olivary complex
WV Midbrain - Answers :Lateral lemniscus terminating in the inferior colliculus
Wave I appearing in contralateral ear recording is - Answers :failure of white noise
masking
Intensity of white noise masking should be - Answers :60 dB SPL
Failure to use white noise masking can produce a - Answers :false negative
CNIM Present ipsilateral response and absent contralateral response can only be
caused by one thing. - Answers :FLUID IN THE HEADBOX/JACKBOX
Most important preparation step in setting up IONM for Vestibular Schwannoma is -
Answers :WATER TIGHT SEAL with tape over ear
Middle Ear Infection is called - Answers :Otitis Media
Causes delayed absolute latencies
Otitis media causes dampening of amplifying effect
Ossicles job is to amplify sound by factor of - Answers :22
Age related HF hearing loss is called - Answers :presbycusis
Ischemia of Cochlea - Answers :Caused by trauma to internal auditory artery
Increase in absolute latencies
hypothermia below 19-20C - Answers :Increase in all interpeak latencies: I-III, III-V, I-V
Global slowing of conduction velocity
Cochlear nucleus lesion - Answers :Increased III-V, I-V
Neurofibromatosis Type II - Answers :Same as vestibular schwannoma
Increased I-III, I-V
Acoustic neuroma, Vestibular schwannoma - Answers :Increased I-III, increased I-V
Pontine Glioma or Midbrain infarction - Answers :Increased III-V, I-V
, Middle Cerebral Artery Infarction affecting Temporal Lobe - Answers :Normal BAEP
Pneumatic Drill & BAEPs - Answers :Prolongued wave V
CNIM will ask is: What type of artifact does the pneumatic drill produce. - Answers
:NONE
What instrument is known to cause a temporary shift in the BAEP? - Answers :The drill
Vestibular Schwannoma - Answers :Slow growing tumors in the cerebellopontine angle
which arise from the Schwann cells covering the vestibular portion of the VIIIth nerve,
hence the name.
Signs and symptoms:
Vertigo/balance disturbance
Hearing loss
Ringing in ear
Suboccipital Approach: Cerebellar retraction causes - Answers :increased wave V
latency (ON EVERY EXAM) and could lead to hearing loss if excessive and persistent
Occlusion of AICA - Answers :which is the parent vessel of the labyrinthine artery
causes infarct of the inner ear (cochlea)
Middle Fossa Approach - Answers :Advantages
Easy access to intracanalicular tumors, especially at the lateral end of the IAC
Hearing preservation in possible
Extradural, therefore low risk of CSF leak
Cochlear Microphonic (CM): Generator of CM is the outer hair cells in the organ of -
Answers :Corti
Alternating clicks used in surgery but NOT with - Answers :EcochG
Electrocochleography
Polarity of the CM waveform is tied to the polarity of the click- DO NOT use alternating
clicks here
Rarefaction - Answers :Negative pressure
Transducer diaphragm moves away from tympanic membrane
Emphasizes wave I amplitude and decreases latency
Condensation - Answers :Positive pressure
