Running an Adult EEG experiment: checklist

Last updated on 19 January 2024 by Charlotte Koevoets

If you have suggestions on how to improve this document, or find mistakes, please send them to ilslabs@nulluu.nl

This is a general checklist for adult EEG experiments. For the infant version of the checklist, please see Running a Baby EEG experiment: checklist.

Warnings

Do not touch volume knobs on speakers, they have been purposefully calibrated for consistency between experiments.
Warning: do not move the participant table in K13. The speaker cables are attached to the rear of the table, and the speaker stands may topple over if the table is moved.

Preparation

In the control room:

Turn on the Recording and the Presentation computers, and turn on all the screens.
- In K.13: the audio mixer is turned on by turning on the ‘Main Power’ plugbox (on the right of the desk).
Turn on the speakers
- In the participant area, turn on the speakers you want by turning on the corresponding plug box in the cabin or participant room. In K.02 the plug boxes are on the right of the participant desk, and in K.13 they are to the left behind the participant desk.
- In K.13: check that the audio switch is set to the correct channel corresponding amplifier. Use channel T for the speakers, and channel E for the eartips amp.
Before the participant is in the lab, run the experiment once to check whether sound and visual stimuli work well.
If necessary, adjust the audio volume using the audio mixer (K13) or using the volume controls in Windows/Linux. Do not touch the volume knobs on the speakers, as they have been purposefully calibrated.

In the test room:

Check the battery power; if the battery is somewhat empty it’s recommended you switch out the battery with the spare one in the control room (which should be full).
- You can check the battery level through ActiView, or by connecting it to the charger. If the charger gives you a green light, it’s good to go. If it’s orange, you should only use it if the other battery is empty as well.
Connect the battery to the amplifier (EEG and ABR experiments use different modules/amplifier): connect 4 sides. Lift the black connector slightly until you hear a click, then close gently. Finally connect the battery to the amplifier with the blue connector in the front.
Put gel into syringe
Get one EEG cap (there’s a size-chart in the closet containing the caps)
Get the electrodes bundle (32 Channel)
Optional (when the air is dry): Turn on the air humidifier (only in K.13)
Check the sound level using the audiometer. A loudness of 65 dB is recommended for the sound stimuli.

Welcome the participant in the waiting area (K.01). Take them to the lab.
Switch off your mobile phone and make sure the participant does the same.
Have the participant remove any jewelry (e.g. necklaces or earrings).
Explain to the participant what the experiment is about and what is expected of them/what they can expect.
Collect consent form from the participant.
Give the participant an instruction of the experiment, e.g. don’t talk during the experiment.

In the test room:

Clean the skin behind the participant’s ear with a cotton pad with alcohol.
Put on the cap.
Put gel into all electrodes.
Put EXG1 on the left mastoid and EXG2 on the right mastoid (if used), connect these two electrodes to the amplifier in the drawer.
Connect electrodes to the corresponding holes in the cap and to the amplifier. Use the portable screen connected to the recording PC video cable in the participant room to monitor the signals from the electrodes while capping.
Turn on the amplifier and check the blue light (the light should start to burn continuously. If the light flickers, this means that the electrodes CMS and DRL aren’t attached properly and may
need more gel).

In the control room:

Click the BioSemi icon on the Recording PC desktop in the control room.
Click “start” on the BioSemi window, you should see all the electrodes now.
Check impedance: go to tab “electrode offset”, set the scale on the left to 50mv, and all the blue bars should be in the range ±25mv.
Optional: Set reference to Cz: go to the tab “monopolar display”. On the left of the screen, click “Free choice” under “Reference”, and use the menu below to select Cz.
Click “Start File” at the right bottom of the BioSemi window.
Type in the participant’s information and save in your data folder.
Click “pause save”, otherwise you are not recording!
Open OBS Studio and click ‘Start recording’.
On Presentation PC, open the experiment file, click run.
Fill in the name of the participant in the pop up window “Enter Subject Name/ID”, in the same format as in ActiView (Recording PC).
Use Enter key on the keyboard to start experiment. Use Esc if you want to abort the experiment.
On the Recording PC, check whether triggers are sent. If not, call lab support.