Actually, it is possible to get feedback from the brain without EEG machines. It takes a bit of training and careful self-observation. I can usually tell when my brain is in a "danger state" when I hear a high-pitched ringing in my right ear (where I'm pretty certain my trigger neurons are). On the other hand, if I sense a low hum in the back of my brain, I tend to be in a relatively peaceful space, less apt to have a seizure. Others may pick up where their brain is at by other internal signals. It is a matter of "listening to the brain".
Nevertheless, I would still like to get hold of a EEG machine to verify this.