A Small Number of Patients in Vegetative State May Be Able to Communicate
In a new study published in the New England Journal of Medicine, British scientists described communication with a 29-year-old Belgian man who sustained brain damage as result of a car accident five years ago. The researchers were also successful in locating signs of consciousness in three other patients through brain-imaging studies, indicating potential for communication with people previously considered unresponsive.
The study, which is being conducted in England and Belgium, is part of a growing body of work changing how people think about the vegetative state, where the body is able to function enough to maintain life, but they are unresponsive to stimuli.
Functional magnetic resonance imaging (fMRI) tests were conducted on a total of 54 patients with severe brain injury. fMRI’s provide a picture of brain activity in real time. Of these, 31 were diagnosed as being in a minimally conscious state, meaning that they showed intermittent signs of awareness such as laughing or crying.
The patients were placed in the MRI scanner and asked to imaging playing tennis, a task that activates the motor cortex, the part of the brain associated with movement. They were given instruction to imagine walking around their home or on familiar city streets to activate spatial navigation centers. Four patients showed sustained patterns of brain activity in the same areas as healthy controls.
The researchers then asked simple yes-no autobiographical questions, such as “Do you have any brothers?” One patient was able to respond correctly to five of the six the questions. Dr. Adrian Owen, a neuroscientist at the Medical Research Council in the UK and lead author of the study, said “There is a minority of vegetative patients who aren’t what they appear to be. They have cognitive capabilities far beyond what they appear capable of.”
Dr. Mark Brooks PhD, a neuropsychologist at Glancy Rehabilitation Center in Georgia said that “The ability to respond to questions via brain activity doesn’t necessarily imply that the person is aware. Awareness is the functional totality of all cognitive skills.” It does however give hope.
According to Dr. Owen, some estimates put misdiagnosis of the vegetative state as high as 40%. It is possible that some of the patients had some consciousness, but that the brain injury left them deaf or otherwise incapable of responding.
He does however warn against over-interpretation of the findings. The ability of these patients is rare and does not apply to all patients in a vegetative state. For example, Terri Schiavo, the Florida woman who had severe brain oxygen depletion without brain trauma, would not have likely been able to respond to questions or direction.