Precise Electrical Stimulation May Lift Patients from Vegetative States

Patients in vegetative states persist in a partially living limbo—they’re not dead, but they also appear unable to return to consciousness.

Doctors and neuroscientists have been unable to revive many of these patients. Their brains have been so damaged that they are dependent on life support to survive, and their prospects worsen the longer they stay in a vegetative state. Yet the recent experience of one such patient suggests that persistent vegetative states may not be permanent.

While the patient showed little activity (seen in the number of connections, with yellow and orange representing higher activity) before stimulation (top), his brain became more active after a month of the treatment.

The patient, a 35-year-old man in France who has been in a vegetative state for 15 years, was roused to a minimally conscious state when Angela Sirigu, a cognitive neuroscientist at the Institute for Cognitive Sciences–Marc Jeannerod in Lyon, France, and her team stimulated his vagus nerve, a key nerve that runs from the brain to the stomach. They sent small electric currents to the nerve from a pacemaker-like device, and after a month, the patient began to show more signs of life.

While he wasn’t fully awake, he could track objects with his eyes, turn his head when asked, and even startle when a doctor suddenly appeared in front of his face. Sirigu’s team continued the stimulation for nine months, at which point they stopped. The patient never advanced beyond minimal consciousness, but he didn’t regress, either.

The takeaways from the experimental treatment are still up for debate. Since only one patient was involved, it’s hard to extrapolate the findings to the larger population of people in vegetative states, which number in the hundreds of thousands. And the methods of the experiment itself may have affected the patent. Here’s Michael Price, reporting for Science:

The surgery to implant the electrical stimulator, the frequent behavioral observations, and the moving in and out of brain scanners all could have contributed to the patient’s improved state, says Andrew Cole, a neurologist at Harvard Medical School in Boston who studies consciousness. “I’m not saying their claim is untrue,” he says. “I’m just saying it’s hard to interpret based on the results as presented.”

Still, other experts are hopeful that vagal nerve stimulation will work in other patients. The technique is already used successfully in some cases of epilepsy and drug-resistant depression.

Read the original article.