A man who had been in a vegetative state for 15 years has shown signs of consciousness following the implantation of a vagus nerve stimulator into his chest. Vagus nerve stimulation (VNS) – the treatment already proven effective in reducing symptoms of depression and epilepsy – can help to restore consciousness even after many years in a vegetative state, researchers say.
The vagus nerve connects the brain to various parts of the body – and even the gut. It’s known to be important in maintaining certain body functions, like in walking and alertness.
In order to test if the VNS would have any effect on bringing a vegetative patient back to consciousness, the team led by Angela Sirigu and colleagues at the French National Centre for Scientific Research in Bron, implanted a vagus nerve stimulator on the chest of a 35-year-old man who had been lying in a vegetative state for more than a decade with no sign of improvement.
After a month of vagal nerve stimulation, the man’s attention, movements and brain activity significantly improved. He was able to respond to simple orders, like following an object with his eyes and turning his head upon request. The researchers also observed the man’s ability to response to “threat” that had been absent – like when the examiner’s head suddenly approached the patient’s face, he reacted with surprise by opening his eyes wide. Examining the patient through EEG and PET scans revealed major changes, too.
“Brain plasticity and brain repair are still possible even when hope seems to have vanished,” Sirigu says in a news release.
The team is now planning a large collaborative study to confirm and extend the therapeutic potential of VNS for patients in a vegetative or minimally conscious state. In addition to helping patients, Sirigu says “the findings will also advance understanding of “this fascinating capacity of our mind to produce conscious experience.”
The study, entitled “Restoring consciousness with vagus nerve stimulation” has been published in the journal Current Biology.