What constitutes consciousness–not in the philosophical sense, but clinically speaking–has been a matter of great debate in scientific circles lately, particularly as new technological applications allow neuroscientists to peek deeper into the brains of those thought to be in vegetative states. Now, a cheap and portable EEG device has been developed that has detected signs of consciousness in three people previously thought to be in vegetative states.
The same team that shook up the established line of thinking back in 2005 by using functional MRI to show consciousness in a person thought to be in a persistent vegetative state (PVS) has now shown that relatively inexpensive electroencephalogram (EEG) can do the same thing. The wide availability and low cost of EEG–which uses electrodes placed on the scalp to sense electrical activity in the brain–spells an accessible bedside solution for determining consciousness where fMRI did not.
The team of researchers behind the new method tried it out on 16 people thought to be in a PVS. The subjects were asked to imagine performing certain physical tasks, like wiggling their toes or making a fist. In three of the subjects, the brain regions that control those actions showed activity when given the command, demonstrating not only that the subject could hear the researchers, but that they could understand and respond accordingly.
It’s difficult to know whether the responses are made consciously or unconsciously without more tests, but the researchers plan to continue pushing forward. Conceivably the EEG method could lead to a means of communicating with patients thought to be in a PVS. And the ability to communicate with those once thought to be unconscious could make them active participants in their own therapies. From there, a brain-computer interface might even grant patients’ even greater communicative skills via a computer with a brain controlled cursor.