BAEP Flashcards
What is the function of bone wax when performing a BAEP?
Securing the earphone. ( IT DOES NOT PROTECT THE CANAL FROM FLUID ENTRY)
Absolute Latency of Wave I?
1.4 msec
Absolute Latency of WIII?
3.4 msec
Absolute Latency of WV?
5.5 msec
Wave I
Distal VIIIth Nerve
WIII
Pons, Superior Olivary Complex
WV
Midbrain, Lateral Lemniscus, Inferior Colliculus
Cz placed in in positive or negative input?
positive
Ai and Ac placed in positive or negative input?
Negative
Auris Sinister (AS)
Left Ear
Auris Dextrous (AD)
Right Ear
Wave I is only recorded in the stimulated ear? True or False
True
White Noise Masking at?
60 dB SPL
Contralateral Channel Function?
- Validates White Noise Masking is being presented at appropriate intensity
- Better identification of Wave V (Better 4-5 split in the contralateral ear)
Failure to use white noise masking may produce?
False Negative meaning the data does not change and the patient awakens with deficit.
Identification of Wave V may require?
Decrease stimulation intensity (by 5 dB HL)
If you have presence in Cz-A1 and absence in Cz-A2?
Technical Issue: Problems with sensitivity or fluid in ear
Absent Cz-A1 and Presence in Cz-A2?
Technical Issue, Cannot be fluid in the ear though because the presence of waves III and V in the contralateral side. Could be fluid in the pod where A1 inserted.
Kinked Earphone Tubing
Increase in Absolute Latency, Normal inter-peak latencies
Blood, Betadine or Irrigation Fluid in Tubing
Increase in Absolute Latency, Normal inter-peak latencies
Excessive Earwax (Serumen)
Increase in Absolute Latency, Normal inter-peak latencies
Perforated or Hardened Tympanic Membrane
Increase in Absolute Latency, Normal inter-peak latencies
Middle Ear Infection (Otitis Media)
Increase in Absolute Latency, Normal inter-peak latencies
Artificial Ventilation
Increase in Absolute Latency, Normal inter-peak latencies
Otosclerosis
Increase in Absolute Latency, Normal inter-peak latencies
Nitrous Oxide
Increase in Absolute Latency, Normal inter-peak latencies
Most important preparation step for BAEP?
Water tight seal of tape over ear
What modality is monitored during cholesteatoma surgery?
Facial Nerve only, CN VII
What modality is monitored during cholesteatoma surgery?
Facial Nerve only, CN VII
What Modality is monitored during Mastoidectomy surgery?
CN VII
What Modality is monitored during tympanoplasty surgery?
CN VII
What modality is monitored during Porus Acusticus Surgery?
CN VII and BAEP
Tinnitus
Ringing in the ear
Meneires Disease Surgery
Endolymphatic Sac Decompression
What modality is monitored during Endolymphatic Sac Decompression Surgery?
CN VII and BAEP
High Frequency Hearing Loss
Normal or near normal at high intensity click stimulation, but at lower intensity stimulation, increased absolute latencies and normal inter-peak latencies
Broad Band Click range
2,000-4,000 Hz
Type of Clicks used in BAEP?
Broad Band Clicks
Presbycusis (definition)
High Frequency hearing loss in old age
Presbycusis
Normal or near normal at high intensity click stimulation, but at lower intensity stimulation, increased absolute latencies and normal inter-peak latencies
Ischemia of the Cochlea
Increase in Absolute Latency, Normal Inter-peak Latencies
Hypothermia
Increase in All Interpeaks: I-III & III-V & I-V
Acoustic Neuroma
Increased I-III, increased I-V inter-peak
Vestibular Schwannoma
Increased I-III, increased I-V inter-peak
Neurofibromatosis Type II
Increased I-III, increased I-V inter-peak
Could have multiple Acoustic Neuromas
Vestibular Schwannoma: Translabyrinthine Approach
Vestibular and Auditory Function on side of Tumor is sacrificed; facial nerve is readily identified
Vestibular Schwannoma: Middle Fossa Approach
Hearing Preservation is possible
Vestibular Schwannoma: Sub occipital/ Retrosigmoid Approach
Hearing Preservation is possible
Cerebellar retraction is necessary
Greater risk of Facial Nerve injury
INCREASED WAVE V LATENCY
Lesion: cochlear Nucleus
Increased III-V, Increased I-V
Pontine Glioma or Lesion at the Rostral Pons
Increased III-V, Increased I-V
