Here you can find some information.
http://www.neuro.comhttp://www.neuro.com/neuroscan/prod03.htm
Event Related Potentials (ERP) seems
to be _a_ way to interpret EEG signals.
I don't know if the methods have
progressed further.
I was 'into' this some time ago, making a one point
pickup in an EMC chamber, hoping to
correlate 'mind activity' with the signal.
I soon realized the difficulty inherent....
Correlation is probably not doable on
a 'hobby' basis, it takes resources+time.
Yours
Patrik Bagge