People in a vegetative state pose a diagnostic problem for physicians. They are wakeful, but unconscious. They open their eyes, but they are unresponsive. They don’t talk or communicate, and they can’t follow the simplest commands to lift a finger or blink. They fall low in the Glasgow coma scale—one step above brain death. Vegetative states that last longer than a year are called “persistent.” Those patients rarely recover and are typically given up for lost forever.
But a new study–published last week (February 3, 2010) in an online version of the prestigious New England Journal of Medicine–gives hope that some consciousness may remain…although buried deep in the brain, accessible only by sophisticated functional MRI.
How fMRI Works
A regular MRI uses magnetic imaging to see the inside the physical brain, the actual structures. The report will be a series of pictures that look similar to an x-ray.
A functional MRI (fMRI), on the other hand, allows us to see the way the brain works. The person whose brain is being scanned is asked to perform a mental task. The process of thinking creates metabolic changes in very specific parts of the brain, and the fMRI can pick up on these changes. The report will show the brain’s pattern of activity before, during, and after doing the mental tasks. (For more information about the fMRI, click here.)
In this study, 54 patients considered to have minimal or vegetative consciousness were asked to perform 2 mental imagery tasks—to imagine playing tennis (swinging a racquet), and then to imaging walking through their home. That let the scientists see the parts of the brain that responded to those images. Of the 54 original patients, five—all of whom had suffered traumatic brain injury—showed the ability to follow the instructions to imagine the scenes
For one vegetative patient, testing went an additional step. That patient was asked simple “yes” or “no” questions (such as “Do you have any brothers?”)… and told to use the images to answer. For example, imaging swinging a tennis racquet if the answer is “yes”…or imaging walking through your home if the answer is “no.”
Since the scan had already shown where those images appeared in the brain, scientists could read the “yes” or “no” answer by where brain activity appeared. That patient was able to answer correctly simply by imaging the scenes.
Where Hope Lies
The lessons of this study can be used to improve diagnosis of people with minimal consciousness. Without motor ability, it is impossible for doctors to know whether conscious brain activity exists. By using fMRI technology, diagnosis and labeling can become more accurate. Some people in vegetative states may be underestimated.
Even more importantly, this study give hope that traumatic brain injury patients may be able to communicate enough to address quality of life issues. For example, may be they could tell us whether they experience pain… if they are comfortable… or any other issues that could help guide treatment. They may be able to make their wishes known. And in the long-run, the medical community will learn more about the depth and scope of consciousness.
This might seem like meager reward for such an extensive study, but for family members, it is the very definition of hope. Think of it this way: If you had the opportunity to ask one “yes” or “no” question of a loved one you thought was lost forever–someone you believed you could never talk to again–what would you ask? I guarantee: The answer would be precious.
(New England Journal of Medicine article: http://content.nejm.org/cgi/content/full/NEJMoa0905370)