Doctors recently restored consciousness to a man living in a 15-year vegetative state by using a new type of nerve stimulation. This could completely redefine how doctors perceive irreparable brain damage; traditionally, most neurologists think that a vegetative state longer than a year could last a lifetime.
The team of neurologists in France has potentially unlocked a way to bring thousands back to consciousness who were previously thought to be 'beyond help.'
"We choose a patient who was in a vegetative state [for] 15 years, showing no sign of change since his car accident," neuroscientist and study co-author Dr. Angela Sirigu said in an email to PBS NewsHour. Nothing else has been made public about the 35-year-old man. Researchers refuse to share his identity and his family has not made a public statement on his behalf.
The vagus nerve
The implant used stimulates the vagus nerve. The vagus nerve is the tenth cranial nerve and one of the most important connections between the head and the rest of the body. It's the longest nerve in the autonomic nervous system in the human body. Researchers have used vagus nerve stimulation (VNS) similar to what the French team used since 1997. It's been effective in controlling seizures in epilepsy patients and it's even been used to help treat clinical depression. VNS treatments have been compared to pacemakers for the brain.
However, the researchers didn't randomly select VNS as a treatment that could work. They spent significant time observing the patient's minimal brain function and preexisting research. Earlier studies suggested that stimulating the thalamus would trigger responses in coordinating sensory signals. The previous research from 2007 also dealt with patients who had undergone extensive brain damage and had been in "disorders of consciousness" longer than 12 months.
The vagus nerve links directly to the thalamus, and thus VNS had previously shown to boost metabolism in that part of the brain. The French team developed a hypothesis that if they used a VNS implant on a vegetative state patient, they could still activate the thalamus.
They measured the man's behavior and recorded an EEG and PET scans of his brain before putting in the VNS implant. The team then gradually increased the power of the current. The patient didn't respond to the VNS until one month into testing when the team had reached 1 milliampere. He started showing "general arousal, sustained attention, body motility, and visual pursuit."
As the doctors continued testing, the patient showed continual improvement.
"The man began responding to simple orders that had been impossible before. For example, he could follow an object with his eyes and turn his head upon request," the team said in a press statement. "His mother reported an improved ability to stay awake when listening to his therapist reading a book."
While one case study doesn't completely validate a new treatment, it does show promising results that -- hopefully -- could be used to restore normality to patients around the world.
"Brain plasticity and brain repair are still possible even when hope seems to have vanished," said Sirigu from the Cognitive Neuroscience Centre.