<p>There are many many reasons why interference can occur so it's almost impossible to give a direct answer with the details provided. You should at least give details like a spectrogram and experimental set-up. In my experiments, most (if not all) issues come down to (1) grounding and (2) line noise. For (1), you want to recheck the connections on all your grounds and ground as many sources of noise as possible. For (2), you'll want to unplug devices near your experiment one-by-one; definitely &quot;unplug&quot; and not &quot;turn off&quot; as many devices will still produce line noise even when ostensibly unpowered.</p>

CC BY-SA 4.0
2023-05-28T19:27:31.383Z
2023-05-28T19:27:31.383Z
Eric Lee
<p>I carried out EEG and EP studies on a daily basis. I occasionally electric artefact present within my studies, despite having my notch filter applied, low impedance, and subjects well grounded.</p>
<p>I figure that due is due to environment (e.g. using metal chair), as it only certain electrodes and the interference is mitigated when  I adjust the wires.</p>
<p>My question why is the electric artefact present, despite the use of filters an earth?</p>
<p>Any insight and references would be great.</p>

CC BY-SA 4.0
2023-05-21T23:06:19.893Z
Do you mean specifically a 60 or 50 Hz oscillation from electrical supply?
Bryan Krause
CC BY-SA 4.0
2023-05-22T11:26:07.480Z
Welcome. Sample data including proper time and voltage axes can help a lot
AliceD
<eeg><signal-processing><evoked-potentials>
Why is Electric Artefact still present in my recording?
user32979
# Why is Electric Artefact still present in my recording?

(Asked by: username_0 on 2023-05-21)

I carried out EEG and EP studies on a daily basis. I occasionally electric artefact present within my studies, despite having my notch filter applied, low impedance, and subjects well grounded.

I figure that due is due to environment (e.g. using metal chair), as it only certain electrodes and the interference is mitigated when I adjust the wires.

My question why is the electric artefact present, despite the use of filters an earth?

Any insight and references would be great.

**Tags:** eeg, signal-processing, evoked-potentials

> **Comments:**
> **username_1**: Do you mean specifically a 60 or 50 Hz oscillation from electrical supply?  
> **username_2**: Welcome. Sample data including proper time and voltage axes can help a lot  

---

## 1 answers

### Answer by username_3 on 2023-05-28. Score: 1

There are many many reasons why interference can occur so it's almost impossible to give a direct answer with the details provided. You should at least give details like a spectrogram and experimental set-up. In my experiments, most (if not all) issues come down to (1) grounding and (2) line noise. For (1), you want to recheck the connections on all your grounds and ground as many sources of noise as possible. For (2), you'll want to unplug devices near your experiment one-by-one; definitely "unplug" and not "turn off" as many devices will still produce line noise even when ostensibly unpowered.


---

