Hello everyone,
I'm a neuroscientist and I'm currently trying to start a project using EEG.
Anyway to cut a long story short, we have been doing EEG for years with no problems, then about 5 weeks ago we encountered a strange source of noise in the data. The noise is at about 31 Hz and it looks like this (see image attached.) It's a weird waveform.
Our EEG technicians have not seen this kind of noise before. It is clearly distinct from the 50 Hz noise that you get from mains power (this is in the UK).
We think that the noise is somehow coming from the ground. This is because it does not appear in "free" pairs of electrodes recording from the air. These pick up lots of 50 Hz noise, but not the 31 Hz.
Anyway we are stumped. We're assuming it is some kind of equipment or electrical device somewhere nearby which is causing this. But it's a busy hospital area so there's equipment all over the place. It would help to know what kind of thing we're looking for... so if anyone could suggest what might be making this waveform?
Thanks!
Jamie
I'm a neuroscientist and I'm currently trying to start a project using EEG.
Anyway to cut a long story short, we have been doing EEG for years with no problems, then about 5 weeks ago we encountered a strange source of noise in the data. The noise is at about 31 Hz and it looks like this (see image attached.) It's a weird waveform.
Our EEG technicians have not seen this kind of noise before. It is clearly distinct from the 50 Hz noise that you get from mains power (this is in the UK).
We think that the noise is somehow coming from the ground. This is because it does not appear in "free" pairs of electrodes recording from the air. These pick up lots of 50 Hz noise, but not the 31 Hz.
Anyway we are stumped. We're assuming it is some kind of equipment or electrical device somewhere nearby which is causing this. But it's a busy hospital area so there's equipment all over the place. It would help to know what kind of thing we're looking for... so if anyone could suggest what might be making this waveform?
Thanks!
Jamie