BioSemi.nl

I am conducting a research with and without pharmacotherapy which means every session takes about 3 hours.
(including a 1 hour break to wait after ingestion of the medication)

We are leaving the cap on and usually after the break (2 hours since the beginning) the electrode become very noisy...
Re ...

I have an extra eeg set which when I hook it & press start the following message appears:

Error 5000 occured at No Incoming Data
Possible reason(s):
ADC-box power is off
or
Optical fiber is disconnected

Since I have another set I isolated the problem to the USB receiver:
the USB link light is ...

Has anyone got good tips for decreasing head movement in kids?
I am investigating kids with ADHD and will appreciate any help on the subject...