EMG and EEG

anramos · Post by **anramos** » Fri Jun 19, 2009 5:41 pm

I want to record simultaneously the EEG and EMG. The EEG will be recorded using 128 channels and the EMG 32, the problem is that two separete systems need to be set up because of the amount of channels used. So my question is if there is a way to synchronize both clocks or what other alternative could I have. Thank you

Post by **Coen** » Mon Jun 22, 2009 12:41 pm

The ActiveTwo AD-box can acquire a total of 280 channels. So, you do not need an second system to measure 128 EEG plus 32 EMG channels (the existing 128-chan AD-box can be expanded with extra channels).

Up to 4 AD-boxes can be daisy chained for (synchronized) measurements on separate subjects. This set up can also be used for simultaneous EEG/EMG/ECG measurements on a single subject (up to 4 synchronized AD-boxes with 152 channels each).

Best regards, Coen (BioSemi)

anramos · Post by **anramos** » Tue Jul 07, 2009 9:07 pm

Thank you for the response. I have another question respect the subject. HOw could I daisy chaned 2 Ad boxes for measurements on separate subjects?

Post by **Coen** » Wed Jul 08, 2009 12:31 pm

The first box in the daisy chain can be left standard, boxes 2, 3 and 4 need to have the "daisy chain option" installed (extra optical input adjacent to the existing optical output). The daisy chain option can be installed on older systems. Daisy chaining works with 2, 3 or 4 boxes.

The boxes are daisy chained with optical fibers (fiber goes form box 1 to box 2, from 2 to 3, 3 to 4, and finally from the last box to the USB receiver). The boxes are on speedmodes 0-3 to set the number in the chain. The software automatically adjust to multibox mode, and acquires 4*152 channels (all stored in one BDF file).

A nice feature is that the boxes are only coupled by optical fibers. So, the 2 (or 3 or 4) subject remain complete galvanically isolated from each other (and for the acquisition computer).

Best regards, Coen (BioSemi)