Strange scale

Discussions
1

Hi Francois,

I recorded EEG with Brain Vision Analyzer. When I open it with EEGLAB with the scale of 50 micro-ampere, the signal looks fine. But to see the signal similarly in Brainstorm, I have to set the scale something like 1000 micro-ampere! I wonder what would be the problem?

Cheers,
Mojtaba

2

Hi Mojtaba,

I guess you’re talking about microVolts.
Depending on the way the signals were processed, especially if many layers of software were used successively, the amplitudes might not be interpreted correctly in the Braintsorm.
If you have unit issues, you can multiply or divide the recordings by 1000 or 10^6.
You can do this with the process “Pre-process > Scale values”.

Francois

3

Note for BrainVision / BrainAmp users:
A bug was found in the application of the channel gain, the amplitudes read where sometimes incorrect.
Please update Brainstorm for reading correct amplitudes from the BrainVision files.