I have copied and pasted some excerpts from a Globe and Mail article written in June 2017. The link is at the bottom if you want to read the whole story. I find it frightening and fascinating how little we still know/understand about the human brain.
Dr. Adrian Owen has devoted his research to reaching out to patients with serious brain damage who exist in a murky state of consciousness. As Owen explains in his new book, Into The Gray Zone: A Neuroscientist Explores the Border Between Life and Death, an estimated 20 per cent of patients whom doctors typically regard as vegetative or non-responsive are more aware than they seem. They can see, hear and understand what's going on around them, but are unable to communicate with the outside world.
Dr. Owen developed techniques – using brain-scanning technology – to determine whether patients are conscious, and eventually to communicate with some of them who are.
If he can bring his research into clinical practice, his findings could have significant implications for the diagnosis and care of severely brain-damaged patients.
What is the difference between being in a vegetative state and being in a coma?
A person in a coma really looks like they're asleep. They have closed eyes, they don't have sleeping and waking cycles, and they very rarely move at all. That's typically the first thing that happens to you after you have a serious brain injury. A coma will rarely last more than a couple of weeks.
After that, some people emerge into a vegetative state, and this is a condition where, now, patients have their eyes open. They look around the room, though not at anything in particular. They'll have sleeping and waking cycles. They'll do spontaneous things such as grunt and snore when they're asleep. And you can exist in that stage for decades. They never respond to any form of external stimulation, which is true of both coma and vegetative state. And that's the basis upon which we've always believed these patients aren't aware.
Some patients who appear to be in a vegetative state – and by that I mean using every clinical tool our best neurologists have available to them, they will make no responses – are actually mentally conscious. They can hear, they can see, but are nevertheless not able to make any responses to the outside world.
I don't for a minute want to suggest all patients are aware or all patients are conscious; the effects of very severe brain damage are devastating. But it's certainly possible some of them have a level of awareness that we don't yet understand.
The goal I've really been pursing in 20 years is to try to return some autonomy and decision-making to patients wherever possible. I see family members making incredibly hard decisions about whether to, for example, withdraw life support in the neurointensive health unit. Given that we now know there are patients who we used to think were incapable of making those decisions, who may well be capable and may well want to make that decision, what I'm trying to do is develop technologies and use neuroscience to try wherever possible to give that voice back to these patients.