Electrophysiological Tests Course (RHS 428)
Brainstem Evoked Response Audiometry (BERA) Lab
Compass II (Nicolet Biomedical Inc.)
Aims:
To introduce students to the ABR procedure.
To assist student to interpret ABR results.
Instructions:
Turn the computer on
From the desktop, double click on the folder (EP 317) to open ABR software.
Start preparing your patient (you patient should be laying down on a bed or sitting on a comfortable chair with his/her head and neck supported and in a relaxing position.
Squeeze a bit of abrasive gel (prepping gel) onto a cotton pad and rub gently at placement sites to remove dead skin.
Use alcohol swaps to clean placement sites.
Apply a small amount of the conductive gel(EEG paste) to the electrodes
Attach the electrodes to placement sites carefully using medical tap without touching the placement site with your fingers.
We will be using 1 channel recording, so 3 electrodes should be coming from the pre-amplifier and be attached to the patient's head as follows:
Electrode Placement:
Cz = high forehead, input 1 (+) noninverting /active electrode to channel 1
A1= mastoid of tested ear (TE) = LE, input 2 (-) inverting/reference electrode to channel 1
A2 = mastoid of nontested ear (NTE) = RE, ground/common
Instruct your patient as follows: "this test requires you to be as quiet as possible, we want you to close your eyes and try to relax as much as you can and if you like to take a nap that’s ok we will wake you up when we are done"
Put the headphones on your partner's ears; make sure that you don't change the electrodes positions.
From the main menu, go to “File”, “File Select”, under file name; enter your patient’s name, press “Esc” to save and exit this window.
A new window should open showing the following:
File:C/EP/your patient name.EP
Record 1
Protocol 1:AEP
From the main menu, go to "Parameters" then "collection parameters".
Keep all settings as they are, only disable channel 2 (type the letter "d" from the keyboard) because we will be doing only 1 channel recording.
Change the intensity level to 70 dBnHL, change the ear to L (type L), press "Esc" to save and exit this window.
After you make sure that all the three electrodes have been properly connected, test electrodes for skin resistance (impedance), do the following to check impedance: