Intraoperative brainstem auditory evoked potentials (BAEP)
What is an IONM BAEPs?
A brainstem auditory evoked potential (BAEP) is an evoked potential caused by an aural stimulus (a sound), usually a series of ‘clicks’.
Electrodes positioned on the scalp record responses to the sounds; these are then observed as a reading on an electroencephalogram (EEG). Responses to aural stimuli originate from relay structures within the brainstem.
BAEPs can be reliably recorded in patients with adequate preoperative hearing function. It allows rapid sampling of the auditory nerve function during surgery.
Surgical irritation of the auditory nerve will show abnormal waves, far before a definitive damage. The surgeon can be warned, and thus, avoiding a hearing damage.
How to prepare for you BAEP test?
Wash your hair the night before.
Eat a normal meal and taking your normal medication on the day of the test should be fine.
You should let the person conducting the test know if you use a hearing aid or have any obvious hearing problems.
What are the risks of BAEP testing?
The BAEP testing procedure is painless and side-effects are very rare. There is a chance you may have some minor skin irritation from the electrodes.
After the procedure is finished, patients are usually able to return home on the same day.
Given that you are well enough, you should be able to drive home after the procedure.
What do I expect during a BAEP test?
The BAEP procedure itself is safe and non-invasive.
For the procedure:
Some electrodes will be glued to particular spots on your scalp or earlobe.
You will be given special headphones or earplugs to wear.
It is important that you listen carefully to what the person conducting the test says and follow their instructions.
You will then listen to a series of ‘clicks’ through headphones.
Responses to the clicks are recorded through the electrodes using special equipment.
After the procedure the electrodes will be removed from your head.
Your doctor will discuss the results of the test with you after they have been analysed; otherwise the referring doctor will.
