Brainstem Auditory Evoked Potentials (BAEP / BAERS) Notes

Comprehensive vocabulary flashcards covering Brainstem Auditory Evoked Potentials (BAEP/BAERS) and neurophysiologic monitoring principles, including anatomical wave generators, alert thresholds, acoustic stimulation parameters, and auditory neurovascular anatomy.

BAEP Measurement of III–V Interpeak

Represents neural conduction through the upper brainstem.

Alternating Clicks

A stimulation polarity technique whose primary benefit is reducing stimulus artifact.

ABR Wave V Generator

Generated within the midbrain, corresponding to the upper brainstem and lateral lemniscus.

Waves I and II Generators

Generated from the vestibulocochlear nerve (cranial nerve VIII), with Wave I arising from the distal auditory nerve and Wave II from the proximal auditory nerve.

Vital Waves

The essential BAEP waveforms monitored during surgical procedures, consisting of Waves I, III, and V.

Ac–Cz Montage Troubleshooting

The step to verify ear insert placement for proper side stimulation if Wave I unexpectedly appears in the contralateral recording channel ($\text{Ac-Cz}$) instead of the ipsilateral channel ($\text{Ai}$).

BAERS Alert Criteria

A critical threshold defined as a Wave V latency prolongation of $> 1\,\text{ms}$ or the total disappearance of Wave V.

CN VII Monitoring

The cranial nerve (facial nerve) that should be actively monitored during acoustic neuroma surgery.

Masking

Contralateral noise presentation that eliminates cross-over auditory responses transmitted via bone conduction.

Trigeminal Nerve EMG Latency

The expected latency of the trigeminal nerve electromyographic (EMG) response, which is $3\text{--}5\,\text{milliseconds}$.

Persistent Loss of BAEP Waveforms

The sustained absence of evoked potentials following a normal baseline, which typically results in a postoperative neurologic deficit.

First Decussation in Auditory Pathway

The crossing of auditory fibers occurring anatomically between Wave III and Wave IV.

Rarefaction Polarity

An acoustic stimulus phase representing negative pressure ($-$) that enhances Wave I amplitude, reduces stimulus artifact, and helps resolve Wave V.

Electrocochleography (ECochG) Polarity Effects

Stimulus polarity configuration in ECochG that allows distinction of the cochlear microphonics with clear attenuation of the summating potential.

Labyrinthine Artery

The vascular structure responsible for arterial blood supply to the cochlea.

Occlusion of Anterior Inferior Cerebellar Artery (AICA)

Vascular compromise of this vessel that leads directly to irreversible hearing loss.