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After 15 years in vegetative state, man responds to nerve stimulation

Susan Scutti, CNN | 9/26/2017, 6 a.m.
A car accident at 20 years old left a French man in a vegetative state for 15 years. But after ...
Credit: Marc Jeannerod/Institut des Sciences Cognitives EEG images show an increase of information sharing across the brain, as evidenced by the yellow and orange colors, following vagus nerve stimulation. In caption

The human brain's 'greater potential'

"The general point here is that taken together with all the other information that we have now, it's very clear that the severely injured human brain has greater potential than it's given credit for," Schiff said. "So you can lay around for years and, in principle, still be responsive to medications, devices and other things."

Even with that much brain injury, you can still "move the dial," said Schiff.

What's new in this study is stimulation of the vagal nerve on the outside of the brain, he said. "The nerve sends impulses down into the stomach area," he explained. Instead, the researchers send impulses up through the nerve, and that activates the brain through multiple synaptic pathways.

In the United States, an estimated 50,000 patients are in a vegetative state, and about 300,000 are in a minimally conscious state, Schiff said.

"We've now known for a long time that we can do something for very severely injured brains, but the science has not been met with any kind of infrastructure to catch up with it," he said. More funding for research is needed, he added.

Dr. James L. Bernat, a professor of neurology and medicine at the Geisel School of Medicine at Dartmouth, referred to the new case report as "provocative" and "exciting."

Bernat, who also was not involved in the research, praised Sirigu and her colleagues for their choice of patient: someone in a long-term vegetative state.

"If they had, for example, chosen someone who had been in a vegetative state for three months after a traumatic brain injury and then showed improvement a month later with the intervention, a critic might say, 'Well, wait a minute. We know that a lot of people who are vegetative for three months spontaneously improve in that time period, so it may not be the intervention,' " Bernat said.

He noted that every case of vegetative state is unique based on what caused damage to the brain, how severe that injury was and what regions were harmed.

A vegetative state can be caused by a variety of injuries, including traumatic brain injury, injury to neurons caused by a lack of oxygen and blood flow during cardiac arrest or meningitis, he explained.

For these reasons, the vagus nerve stimulation technique will not work with all patients, Bernat noted, still it's worth doing more studies to find out which patients will benefit from it.

A better understanding of how brain damage harms consciousness would involve learning about how the brain maps the pathways of normal consciousness, said Bernat. "How does normal consciousness occur? And how does unconscious occur?" Bernat asked. "There's a lot of basic work that needs to be done."

Plausibly, this work would also contribute to explaining neurodegenerative diseases, like Alzheimer's disease, as well as cognitive impairment resulting from traumatic brain injury.

New research of consciousness "has the potential to extend beyond the relatively small group of people who have these conditions," said Bernat. Consciousness disorders are, in a sense, "an orphan group of diseases that has been somewhat neglected, not entirely, but somewhat by funding agencies," Bernat said. "I would like to see more funding for research."

Sirigu said she is planning a large study involving collaboration with several research centers to confirm and extend the therapeutic potential of the vagus nerve stimulation technique.

"More basic research will also be important for advancing our understanding of this fascinating capacity of our mind to produce conscious experience," she said.