Vegetative Patients Talk With Brain
A Few Patients in Vegetative State Signal Awareness by Changing Brain Activity at Will
Feb. 3, 2010 - A few patients who appear to be in a persistent vegetative state may in fact be aware of themselves and their surroundings.
Remarkably, such patients may be able to learn to "speak" using only their brains, suggest findings by Martin M. Monti, PhD, of the UK Medical Research Council, and colleagues.
"If someone can produce a mental state on command, it is like having a language," Monti tells WebMD. "We had 23 apparently vegetative patients, and four were really aware -- as we could tell by MRI [brain scans]."
The findings do not mean that all patients in a vegetative state really are conscious beings trapped in an immovable body, Monti is quick to point out. Only a small minority of patients seem capable of activating their brains at will.
Even patients capable of this limited form of communication may not be fully conscious.
"It is not fair to say these patients are just like you and I who are stuck in their bodies," Monti says. "We don't know what is the mental life of these patients. We don't know if they have the same stream of thoughts we have. But these are very important questions."
Talking With the Brain
Monti and colleagues studied 23 patients diagnosed as being in a vegetative state and 31 patients diagnosed as being in a minimally conscious state. Vegetative patients may be able to open their eyes when awake and may have some muscle reflexes, but cannot respond intentionally. Patients in a minimally conscious state are able to make minimal, inconsistent responses to commands but cannot communicate interactively.
All 54 of these patients with severe brain injury underwent functional magnetic resonance imaging (fMRI), a type of real-time brain scan that shows which parts of the brain are active.
The patients were asked to imagine standing on a tennis court and swinging a racquet to hit a ball back and forth with an instructor. Then they were asked to imagine navigating through a familiar room or driving through a familiar neighborhood. Studies of normal people show that each of these mental tasks activates a different brain region.