Irregular signal noise

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enadler12
Posts: 1
Joined: Fri Jan 17, 2025 9:29 pm

Irregular signal noise

Post by enadler12 »

Hi:

We are recording EEG using a Biosemi ActiveTwo box (64 channel cap). All of our equipment is new and electrodes passed the bucket test. We have had many successful sessions, but recently have been running into an issue where all channels have noise, despite electrode offsets starting between +-20 mV. This signal will change throughout the course of a session, improving for a few minutes and then worsening again, despite no changes being made to the cap or electrode. Additionally, there are sometimes unstable electrode offsets which change throughout the course of the experiment.

Here are two images showing the signal noise we are experiencing:
https://drive.google.com/file/d/13JZFmR ... sp=sharing
https://drive.google.com/file/d/1nhemh3 ... sp=sharing

Additionally, we had one participant with extreme signal noise. She had a top and bottom metal permanent retainer, and a metal earring she coulnd't remove, which we thought might be the cause of this noise. Thoughts?
https://drive.google.com/file/d/1qqNeKt ... sp=sharing

Any help would be appreciated!

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