Various medical experts have unveiled several signatures in the brains of people in vegetative states that shows signs of slight consciousness. Doctors generally hold these patients that have critical brain injuries – being unaware of the world around them although they remain awake.
Researchers hope their work will help identify those who are actually conscious, but unable to communicate.
Their report appears in PLoS Computational Biology.
Awake but unaware
After catastrophic brain injuries, for example due to car crashes or major heart attacks, some people can appear to wake up yet do not respond to events around them.
Doctors describe these patients as being in a vegetative state.
Patients typically open their eyes and look around, but cannot react to commands or make any purposeful movements. Some people remain in this state for many years.
But a handful of recent studies have questioned this diagnosis – suggesting some patients may actually be aware of what is going on around them, but unable to communicate.
A team of scientists at Cambridge University studied 13 patients in vegetative states, mapping the electrical activity of their nerves using a mesh of electrodes applied to their scalps.
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Dr Srivas Chenn, and Sandra Bell whose son is in a vegetative state, spoke to Today
The electrical patterns and connections they recorded were then compared with healthy volunteers.
The study reveals four of the 13 patients had an electrical signature that was very similar to those seen in the volunteers.
Dr Srivas Chennu, who led the research, said: “This suggests some of the brain networks that support consciousness in healthy adults may be well-preserved in a number of people in persistent vegetative state too.”
In the second stage of their experiment, scientists arranged for these four patients to have their brains scanned using an MRI machine while being asked to imagine playing tennis.
Previous research shows the area of the brain linked to planning movement lights up when some people in vegetative states performed the task.
And the Cambridge team found three of their patients had similar results – suggesting they were conscious enough to understand a command and to decide to follow it through.
Dr Chennu added: “This type of information might be helpful for families and the healthcare team looking after the patient.
“We have heard anecdotally that carers change their level of interaction with patients once they know there may be some hope of awareness.”
Doctors are equally involved in the research, said there were some limitations to the test, but given the other tests, it could help in the clinical assessment of suffering patients,” said Dr. Trisan Bekinschtein.
If a patient’s awareness networks are constant then we know that they are probably aware of the affairs happening around them,” added Dr Trisan.