New research suggests that the brains of patients in a vegetative state – meaning patients are awake with no signs of awareness – may be able to recognize photographs of friends and family, and make emotional connections. This is according to a study published in the journal PLOS One.
Traditional belief is that when a person is in a vegetative state, they are completely unaware of what is around them. They are no longer able to think, relate to their surrounding environment, recognize the presence of loved ones, or experience emotion or discomfort.
But researchers from Tel Aviv University and the Tel Aviv Sourasky Medical Center in Israel, who conducted this most recent study, say the use of functional magnetic resonance imaging (fMRI) in recent years has opened up a new world in which they are able to monitor the brain activity of these patients.
From this, it has been found that some patients in a vegetative state are able to imagine certain tasks when asked to do so, such as playing tennis, and even respond to yes-or-no questions.
But the researchers note that these rare occurrences do not provide insight as to whether these patients are experiencing emotions during these tasks.
The investigators monitored the brain activity of four patients who were in either a persistent (1-month long) or permanent (more than 3 months) vegetative state.
All patients were shown photographs of individuals they personally knew and some they did not personally know.
The researchers were able to see the patients’ brain reactions using fMRI. This imaging technique measures blood flow to the brain, which allows areas of neurological activity to be detected.
All photographs triggered activity in an area of the patients’ brains that is linked to facial recognition. This showed that their brains had identified that they were looking at faces.
But when the patients were shown photographs of close friends and family members, this triggered brain activity in areas of their brains associated with emotional significance and autobiographical information.
The researchers say this is a groundbreaking discovery, as it indicates that patients in a vegetative state are able to register and categorize detailed visual information and link this to memories.
To see whether these patients were aware of their emotions, they were asked verbally to imagine their parents’ faces.
From this activity, one patient demonstrated activity in the brain regions associated with face recognition and emotion, while another patient showed activity in the emotion-specific brain region only.
The brain activity these patients displayed was identical to the brain activity of healthy individuals, the investigators note.
They add that both of these patients awoke 2 months after these tests, and they did not recall being in a vegetative state.
Commenting on their findings, Dr. Haggai Sharon of the Functional Brain Center at Tel Aviv University and one of the study authors, says:
“We showed that patients in a vegetative state can react differently to different stimuli in the environment depending on their emotional value.
It’s not a generic thing; it’s personal and autobiographical. We engaged the person, the individual, inside the patient.”
The investigators say they have begun research analyzing patients in a minimally conscious state, in order to gain a better understanding as to how brain regions communicate in response to familiarities.
They hope their research will eventually help to improve the care and treatment of patients who are in minimally conscious or vegetative states.
Medical News Today recently reported on a study suggesting that the brain shows signs of consciousness when under general anesthetic.