[Eeglablist] EEGs in mobile/portable office trailers

[Dr. Michael Villanueva]

Hello Ingmar
I have substantial field experience (remote and urban) with mobile/portable EEG devices in different parts of the world under harsh conditions.

Some locations were noisy with 60 Hz, and sometimes a poor (or bad) ground was in the mix. However, a Trifield meter helped us understand the severity of a problem. What we found much worse was fluctuating air conditioning. In locations that were exceptionally hot and humid, it would take the human body a while to adapt to the change in temperature in the mobile unit. We had EEG recordings that showed steep, undulating waves across all channels due to skin pores that would open and close to control sweating. The microscopic ebbing and flowing of sweat alters the EEG. Finally, in some places, it proved impossible to prevent outside noise. We would get an unexpected muscle and audio orientation to sudden noises that regularly passed through the corrugated walls.

For us, in order of frequency occurrence:
1. Audio noise from outside the unit that evoked an audio potential.
2. Sweat-induced artifact.
3. Poor grounding of the unit's electrical system. However, I do not understand electricity, so what we call lousy grounding might have been something else. I can say that the EEG would show a very peculiar jittery square wave morphology. Nonetheless, preprocessing resolved most of the problems, and ASR benefited the sweat artifact.

Michael

-----Original Message-----
From: eeglablist <eeglablist-bounces at sccn.ucsd.edu> On Behalf Of Ingmar Brilmayer via eeglablist
Sent: Tuesday, June 27, 2023 1:56 AM
To: eeglablist at sccn.ucsd.edu
Subject: [Eeglablist] EEGs in mobile/portable office trailers

Dear list,

I wanted to ask if anyone has experience with measuring EEGs in mobile/portable office trailers. Our laboratory spaces are being renovated and/or moved to another building, and we are currently thinking about how to manage the (as we assume quite long) transition period. Do you think there could be any issues with interference or similar problems? After all, such containers are typically made of metal and the wiring might also be, say, "improvised" compared to our lab building. Also, with trams and trains in the city, we thought that this "container solution" might, all in all, be potentially problematic. Thank you in advance for your expertise!

Ingmar

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