people who are in vegetative or minimally-conscious states may be capable of
paying attention and answering simple questions with their minds, suggests a new Canadian study of three people.
Using specialised MRI machines, researchers
found the brains of patients who
were physically non-responsive lit up on cue when the patients were told to
answer yes or no questions or pay attention to specific words.
questions that we posed to ourselves were whether patients who are completely non-responsive... have the ability to
pay attention and whether we can use this as a way to communicate with
them," Lorina Naci, the study's lead author from Western University in
London, Ontario, told Reuters Health.
research found that some people with no outward signs of consciousness after
severe brain injuries can increase their brain activity when prompted.
known, however, about whether those patients could focus on specific commands
and maintain that focus for prolonged periods of time.
For the new
study, Naci and her colleague Adrian Owen looked at three patients who suffered
severe brain injuries and were left in minimally-conscious or vegetative
The patients were put through a functional
magnetic resonance imaging scan that measures the amount of blood flow in
certain parts of the brain, which is used as a measurement of brain activity.
making sure the patients could hear, the researchers tested whether they could
follow commands by playing a series of sounds and telling patients to pay attention
or not pay attention.
compared the patients' brain scans to see whether there were differences on the
images. Overall, the patients' scans showed more activity following the orders
to pay attention.
What's more, two of the patients who completed
additional testing were able to pick specific words in a series to recognise.
Their scans showed more activity when those words were said.
They could also respond to basic yes or no
questions about themselves and their surroundings.
Patients would be asked a yes or no question
and their brain scan would light up when the researchers said the correct
example, they could respond no to the question, "Are you in a
supermarket?" and yes to, "Are you in a hospital?"
scanned the patient in two scanning visits five months apart and we found that
the patients activated the same brain regions," Naci said."We are 99%
confident in the results... we can deduce that it is significant and driven by
the patient," she said.
think the upshot of this is that there is enough data now to know that patients
are being misidentified as unconscious when they have levels of
consciousness," Dr Nicholas Schiff, a neurologist at Weill Cornell Medical
College in New York, who wasn't involved in the new research, told Reuters
Bernat, who studies brain death at the Geisel School of Medicine at Dartmouth
in Lebanon, New Hampshire, said the new study brings to light several points,
including the need for new tests to diagnose patients' levels of consciousness.
used to think prior to seven years ago that a properly performed neurologic
examination (not including functional MRI)... would be the optimal way to
demonstrate whether or not a patient had awareness," Bernat, who wrote an
editorial accompanying the new study in JAMA Neurology, told Reuters Health.
needed to find out how many people diagnosed as minimally-conscious or
vegetative may actually be mentally aware, according to Naci.
that her team is currently working to develop portable brain-scanning devices
and collaborating with philosophers and doctors to decide whether these
minimally-conscious people can participate in their own care and make
decisions." The hope for these patients is to take back some sense of their
autonomy of their own fates," she said.