This past week, I got to be the guinea pig during EEG training for lab members. For once, instead of being the one doing the poking and measuring and taping, I was the one being poked and measured and taped. Because most of you reading this have probably never done an EEG study before, I thought I would take this chance to explain to you what happens in our lab during the EEG portion.
First, we make sure that the skin on the participant’s face where the electrodes will go is clean. Then, we measure the circumference of the participant’s head so that we can get the right sized cap. Since our study runs 8-12 year old children, most of them wear small caps. Apparently I have a larger head though, because at just over 56 cm I fit into a medium cap.
Once the cap is on, we measure the cap to make sure it is positioned properly, and we shift it if necessary. And then we measure and shift and measure until it’s exactly where it should be. A chinstrap helps keep the cap in place. The loose electrodes in the front are then attached to the participant’s forehead, nose, and cheeks so that we can measure eye movements. We attach them with something that is probably best described as a special double-sided sticky tape. It does feel a bit strange at first because your natural reaction to having something stuck on your skin is to get it off, but after a few minutes you don’t really notice them.
Once all of the electrodes are properly arranged on the participant’s head, we begin filling them with electrode gel to establish a connection between the skin and the electrode. Again, it does feel a bit odd at first (mostly cool, and sort of like someone has squeezed a spot of hair gel onto your scalp), but it’s not bothersome. At the end of the experiment, we remind the participant that the small spots of electrode gel will wash right out with water. It will also wash out of clothing, as most of my wardrobe has discovered at one point or another.
So that’s what happens to get set up for an EEG study! Although it was fun being the participant for the day, I think I’ll enjoy going to back to running the studies.