November 3, 2013
Patients In A Vegetative State May One Day Interact With The Outside World
Alan McStravick for redOrbit.com - Your Universe Online
The concept of being in a coma or vegetative state is only made the more frightening when you add in the possibility that while lying there, hooked to medical equipment and having one’s life prolonged by a support system, a cognizance of one’s surroundings damns you to a waking nightmare of unknown duration. Thankfully, those in a vegetative state are spared this scenario. Or are they?According to a new study, a patient who was seemingly in a vegetative state and lacked the ability to move or speak actually exhibited signs of what the researchers term as ‘attentive awareness.’ The study claims the patient was able to focus on words the researchers signaled as auditory targets. The patient, they state, was able to focus with the same intensity as a healthy individual. If these results can be replicated with any consistency with other patients who are vegetative, the possibility for the development of specialized devices allowing other patients to communicate with the outside world comes closer to becoming a reality.
The results of this study, conducted by scientists at the Medical Research Council Cognition and Brain Sciences Unit at the University of Cambridge, were published, somewhat appropriately, on Halloween in the journal Neuroimage: Clinical.
A total of 21 vegetative or minimally conscious patients were observed for the study via the use of electroencephalography (EEG). An EEG measures the electrical activity of the brain in a non-invasive manner over the scalp of the subject. Additionally, the team observed eight healthy volunteers in the same manner.
Each participant was subjected to hearing a series of different words – one word a second for a 90 seconds – while being asked to alternatively recognize either the word ‘yes’ or the word ‘no,’ each of which appeared 15 percent of the time. This process was repeated several times over a half hour period. The intention was to find whether or not the subject was able to identify the correct target word.
While seeking the target word, participants heard ‘worm’, ‘moth’, ‘moss’ and ‘toad’, among other words. As the string of words rattled off, the team discovered one vegetative patient who they determined was able to filter out the unimportant information and hone in on the relevant word they were being asked to pay attention to.
Further work with this patient, while employing functional magnetic resonance imaging (fMRI), showed the researchers the patient was able to follow simple commands, such as imagining playing tennis. Additional work with three of the minimally conscious patients showed they reacted to some of the novel but irrelevant words broadcast to them, but were unable to selectively pay attention to the target word.
It is this last finding that is indicative of the waking nightmare alluded to above. According to the researchers, it is this finding which suggests some patients in a vegetative or minimally conscious state may, in fact, be able to recognize and direct their attention to sounds in the world around them.
According to Dr. Srivas Chennu of the University of Cambridge, “Not only did we find the patient had the ability to pay attention, we also found independent evidence of their ability to follow commands – information which could enable the development of future technology to help patients in a vegetative state communicate with the outside world."
"In order to try and assess the true level of brain function and awareness that survives in the vegetative and minimally conscious states, we are progressively building up a fuller picture of the sensory, perceptual and cognitive abilities in patients,” Chennu continued. “This study has added a key piece to that puzzle, and provided a tremendous amount of insight into the ability of these patients to pay attention."
For his part in the research, Dr. Tristan Bekinschtein of the Medical Research Council Cognition and Brain Sciences Unit stated, “Our attention can be drawn to something by its strangeness or novelty, or we can consciously decide to pay attention to it. A lot of cognitive neuroscience research tells us that we have distinct patterns in the brain for both forms of attention, which we can measure even when the individual is unable to speak.”
Concluding his statement he said, “These findings mean that, in certain cases of individuals who are vegetative, we might be able to enhance this ability and improve their level of communication with the outside world.”
This latest study is a continuation of a joint program of research between the two organizations. They both have committed a team of researchers who have been developing a series of diagnostic and prognostic tools based on brain imaging techniques since 1998. Previous work by the team, completed in 2006, put them on the map when they were able to show how a patient in a vegetative state, again through the use of fMRI imaging techniques, was able to respond to yes or no questions by indicating different, distinct patterns of brain activity.
While this writer sincerely hopes never to be relegated to the unfortunate state of minimal consciousness, if the fates will it, I hope they will wait until this team develops the technologies making communication with the outside world a reality.
Image 2 (below): This scan depicts patterns of the vegetative patient's electrical activity over the head when they attended to the designated words, and when they when they were distracted by novel but irrelevant words. Credit: Clinical Neurosciences