Tag Archives: EEG

EEG device detects consciousness in persons in persistent vegetative state

Here’s an interesting article from the New Scientist.

Excerpt:

Signs of consciousness have been detected in three people previously thought to be in a vegetative state, with the help of a cheap, portable device that can be used at the bedside.

“There’s a man here who technically meets all the internationally agreed criteria for being in a vegetative state, yet he can generate 200 responses [to direct commands] with his brain,” says Adrian Owen of the University of Western Ontario. “Clearly this guy is not in a true vegetative state. He’s probably as conscious as you or I are.”

[Owen’s team] devised a test that uses the relatively inexpensive and widely available electroencephalogram (EEG).

An EEG uses electrodes attached to the scalp to record electrical activity in the brain.

Owen and his team used an EEG on 16 people thought to be in a PVS and compared the results with 12 healthy controls while they were asked to imagine performing a series of tasks.

Each person was asked to imagine at least four separate actions – either clenching their right fist or wiggling their toes.

In three of the people with PVS, brain regions known to be associated with those tasks lit up with activity, despite physical unresponsiveness. This suggested to the researchers that the subjects were carrying out a complex set of cognitive functions including hearing the command, understanding language, sustaining attention and tapping into working memory.

“It isn’t the case that just because somebody doesn’t respond they’re not conscious,” Owen says. “There’s a growing body of data now demonstrating that many of these patients aren’t what they appear.”

The rest of the article talks about how the scientists are planning to use their new technique to communicate with patients by asking them to think of specific things which will mean “yes” or “no”. The long-term goal is to get the patients to be able to communicate, perhaps even allow them to move a mouse pointer by triggering reactions in their brains by using their thoughts.

I think this research dovetails nicely with the OCD research I mentioned before. Maybe now would be a good time to talk more about that research.

William Dembski discusses the OCD research of Jeffrey Schwartz.

Excerpt:

Schwartz provides a nonmaterialist interpretation of neuroscience and argues that this interpretation is more compelling than the standard materialist interpretation. He arrived at this position as a psychiatrist specializing in the treatment of obsessive-compulsive disorder (OCD). OCD sufferers recognize obsessive-compulsive thoughts and urges as separate from their intrinsic selves. For instance, after a few washings, the compulsive hand-washer realizes that his hands are clean and yet feels driven to keep washing them. It was reflection on this difference between the obvious truth (the hands are clean) and the irrational doubts (they might still be dirty) that prompted Schwartz to reassess the philosophical underpinnings of neuroscience.

From brain scans, Schwartz found that certain regions in the brain of OCD patients (the caudate nucleus in particular) exhibited abnormal patterns of activity. By itself this finding is consistent with a materialist view of mind (if, as materialism requires, the brain enables the mind, then abnormal patterns of brain activity are likely to be correlated with dysfunctional mental states). Nonetheless, having found abnormal patterns of brain activity, Schwartz then had OCD patients engage in intensive mental effort through what he called relabeling, reattributing, refocusing, and revaluing (the 4 Rs). In the case of compulsive hand-washing, this involved a patient acknowledging that his hands were in fact clean (relabeling); attributing anxieties and doubts about his hands being dirty to a misfunctioning brain (reattributing); directing his thoughts and actions away from handwashing and toward productive ends (refocusing); and, lastly, understanding at a deep level the senselessness of OCD messages (revaluing).

Schwartz documents not only that patients who undertook this therapy experienced considerable relief from OCD symptoms, but also that their brain scans indicated a lasting realignment of brain-activity patterns. Thus, without any intervention directly affecting their brains, OCD patients were able to reorganize their brains by intentionally modifying their thoughts and behaviors. The important point for Schwartz here is not simply that modified thoughts and behaviors permanently altered patterns of brain activity, but that such modifications resulted from, as he calls it, “mindful attention”-conscious and purposive thoughts or actions in which the agent adopts the stance of a detached observer.

It turns out that people can freely choose to exert “mental effort” in order to change what their brains are doing.

By the way, if you like this topic, and want a resource to show your friends, be sure and get a hold of the debate on mind vs. brain between Jeffrey M. Schwartz and Michael Shermer.