[FieldTrip] excessive channel correlations
roycox.roycox at gmail.com
Thu Apr 12 20:54:40 CEST 2018
hello EEG community,
We have a rather peculiar problem that we're hoping to get some input on.
In reviewing some existing 64-channel recordings, we noticed that some
records show near-identical signals across al channels, with median
channel-by-channel correlations of >0.99. This suggests some kind of
electrical shorting, somewhere in the
The problem appears to be infrequent (most records have more acceptable R
values of 0.6-0.9), but common enough that we'll need to review several
We haven't been able to identify the cause of the problem yet, and it
affects ongoing data collection.
- we use Grass AURA amplifiers and TWin software with the Easycap system
- the problem has been observed with different amplifiers, different caps,
different pcs, and at different sites
- the problem is there regardless of reference montage (e.g., forehead and
- gel bridging, while theoretically possible, seems unlikely given that
literally all EEG channels are (almost) identical
We're still investigating but wanted to hear if anyone ever observed
anything like this? Were they able to solve it?
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the fieldtrip