Posts Tagged ‘Persistent vegetative state’

An AP story being reported on Fox News today, Vegetative Brains Show Signs of Awareness, Study Shows.

It seems that researchers have found a rudimentary means of assessing the ability of people in persistent vegetative states to communicate. From the article:

NEW YORK — Scientists have detected glimmers of awareness in some vegetative brain-injury patients and have even communicated with one of them — findings that push the boundaries of how to assess and care for such people.

The new research suggests that standard tests may overlook patients who have some consciousness, and that someday some kind of communication may be possible.

In the strongest example, a 29-year-old patient was able to answer yes-or-no questions by visualizing specific scenes the doctors asked him to imagine. The two visualizations sparked different brain activity viewed through a scanning machine.

“We were stunned when this happened,” said one study author, Martin Monti of Medical Research Council Cognitive and Brain Sciences Unit in Cambridge, England. “I find it literally amazing. This was a patient who was believed to be vegetative for five years.”

Ever since a research paper four years ago showed apparent signs of awareness in a vegetative patient — one who was included in the new study — families of patients have been clamoring for brain scans, said Dr. James Bernat of Dartmouth Medical School, a spokesman for the American Academy of Neurology.

In fact, a spokeswoman for a patient advocacy group said the organization will urge families to ask about the type of brain imaging used by the researchers.

But experts said more study is needed before the specialized brain scans could be used routinely. “It’s still a research tool,” Bernat said.

The study appears in the New England Journal of Medicine online and can be obtained by clicking the link below:

Willful Modulation of Brain Activity in Disorders of Consciousness
Martin M. Monti, Ph.D., Audrey Vanhaudenhuyse, M.Sc., Martin R. Coleman, Ph.D., Melanie Boly, M.D., John D. Pickard, F.R.C.S., F.Med.Sci., Luaba Tshibanda, M.D., Adrian M. Owen, Ph.D., and Steven Laureys, M.D., Ph.D.

This study is nothing short of astounding and opens the door to a revolution in the medical, ethical, and legal issues surrounding patients in persistent vegetative states. Care must be taken to note the limitations of the study. First, it’s important to note that 5 of 54 patients tested showed responses. Of these, all five were traumatic brain injury patients and not patients who suffered oxygen deprivation (from a heart attack, for example). Nevertheless, some important facts need to be addressed here.

First, there are two major nervous system pathways. Afferent pathways are those which pass from the sense organs and structures and go to the brain.

Efferent Pathways come from the brain to the periphery and are responsible for responding.

A neurological question that has long nagged many has been whether or not there is some level of awareness that simply cannot be ascertained because of damage to the efferent pathways. Clearly there is some level of awareness for some of these patients that we have been able to ascertain by asking them to visualize something specific and then looking for increased brain activity in the same center activated in healthy control subjects when given the same instruction.

The study raises the issue of just how much brain activity is involved in self-awareness and awareness of one’s surroundings. It also raises the specter of people being put to death who are aware and unable to respond, and opens new vistas in therapeutic stimulation and communicating to see if a patient is in pain and in need of analgesics.

Also, we know little to nothing about how the brain repairs itself. We do know that peripheral nerves (those in the limbs for instance) repair at the rate of slow axonal transport, which is ~1mm/day, or roughly 1 inch per month. How long would it take the brain, and under what sort of stimulation?

The brain is the final frontier, and these are very exciting times in science and medicine.

Read Full Post »

%d bloggers like this: