Comatose But Conscious

Anyone who has had a family member in a coma from a brain injury has probably wondered whether their loved one could hear them and wondered what it must be like for someone to be conscious but completely unable to express themselves. We've discussed this on VP on several occasions in the past but whenever I come across an article on the topic, I feel like I should mention it again.

In a partial transcript of a podcast interview with neuroscientist Michael Egnor, Egnor elaborates on the work of Adrian Owen who discovered about fifteen years ago that many comatose patients were capable of thinking and could hear what was being said to them.

Subsequent research has determined that in a significant number of cases, as high as 40%, comatose patients are indeed able to hear what is being said to them and, with modern MRI techniques, even able to respond.

Here's part of Egnor's discussion of Owen's work:

Owen took a woman who was in a persistent vegetative state—she’d been in a car accident and had severe brain damage, and she’d been in this state for several years—and he put her in an MRI machine and did what’s called a functional MRI test. A functional MRI test looks at changes in blood flow in the brain that we believe correspond to activation of parts of the brain. So you can kind of tell what’s going on inside the brain during the time they’re in the machine.

So he put her in the machine and he put headphones on her and he asked her to think about things. Now remember, she’s a woman who, supposedly, is the deepest level of coma, just a hair above brain dead. And he said, “Imagine you’re walking across the room.” “Imagine you’re playing tennis.” “Think of things.” And he found activation in her brain. Even though she had massive brain damage, there were patterns of activation.

So he then took fifteen normal volunteers, put them in the machine, and asked them the same questions. And her patterns of activation were identical to theirs. So he said, well, to a first approximation, it looks like she can think just like they can think.

But, he said, you know, maybe the activation that we are seeing in the brain isn’t because she understands. Maybe it’s just the brain’s reaction to sound. Maybe it doesn’t necessarily mean that you understand, maybe just the noise from the headphones is causing this activation. So he scrambled the words so, instead of saying, “Imagine walking across a room” he would say “across walking imagine room your”. So it made no sense. And the activation went away in her brain and in the volunteers’.

So he showed that the only time she had activation in her brain was when what was asked of her made sense. And her activation was completely indistinguishable from the activation of completely conscious people. So he concluded that she was able to understand and think about things that he was asking her to understand and think about, even though she was in the deepest level of coma.

This alone is astonishing, but there's more:

His research has been repeated by a number of other laboratories on many, many patients with persistent vegetative state. And about forty percent of people in persistent vegetative state show high levels of intellectual functioning even in deep coma.

There are ways of conversing with people in deep coma where you can, for example, look at the activation state representing "Yes" and the activation state representing "No" and you can ask them questions. You know, “Are you lonely?” “Do you wish your mother were here?” “Would you like something to eat?”, stuff like that, and they can answer you, with these brain states.

In addition, some people can do mathematics in a coma. You can ask them “Is the square root of 25, 6?” and they do a "No." And “Is it 5?” and they do a "Yes." So there can be very high levels—not in all patients that we have found—but in many patients, forty percent, at least—of mental function in profoundly damaged brains. To the point where the medical profession has actually added a category to this list of ways you can be in a coma, and this is called minimally conscious state.

So patients who have evidence of intellectual functioning in deep coma are called “minimally conscious,” although, frankly, they’re not really minimally conscious, they’re quite conscious.

I've always wondered whether the comatose patient was in pain but unable to communicate their suffering to anyone. If so, it would be hellish. These sorts of developments give hope that medical professionals will be better able to care for and comfort those who appear to be unconscious but aren't.