A 35-year-old patient in France who has been in a vegetative state for last 15 years demonstrated signs of awareness after scientists electrically stimulated the patient’s vagus nerve, according to a study published in Cell this week.
After nerve stimulation, the patient was able to follow an object with his eyes and turn his head when asked, the scientists reported.
“These findings show that stimulation of the vagus nerve promoted the spread of cortical signals and caused an increase of metabolic activity leading to behavioral improvement as measured with the CRS-R scale and as reported by clinicians and family members,” the researchers wrote.
“Thus, potentiating vagus nerve inputs to the brain helps to restore consciousness even after many years of being in a vegetative state, thus challenging the belief that disorders of consciousness persisting after 12 months are irreversible.”
The team noted that EEG scans demonstrated an increase in theta band power after stimulation, particularly in the parietal, temporal and occipital regions of the brain. This part of the brain is known as a “hot-zone for conscious awareness,” according to the researchers.
Although the approach was successful for this France-based patient and has worked with a few others around the globe, nerve stimulation as a means to awaken vegetative patients has yet to be studied in a major trial.
There’s “strongly accumulating evidence that it is possible in many cases to increase brain activity after severe injury,” Dr. Nicholas Schiff, a neurologist at Weill Cornell Medicine and New York Presbyterian, told Stat.
But he added that “there is essentially no infrastructure to have clinical follow-up” or “larger investigative studies.”