Lyon, France. Sept 25: A bioelectronic implant has brought a 35-year-old French man back to partial consciousness 15 years after a car accident condemned him to a vegetative state. The man has recovered his ability to turn his head, listen to stories and respond to directions after six months of treatment with the device, which pumps a gentle current into a nerve in his neck. It is thought to be the first time that a therapy has roused a patient from a near-comatose condition for more than a temporary respite and without highly invasive brain surgery.
The patient had been brought into hospital with extensive brain injuries, including two haemorrhages, a fractured skull and bruised grey matter. Over the next month he slipped into a persistent vegetative state, an unresponsive condition that is usually irreversible after it has been established for longer than a year.
Marc Guenot and Pierre Bourdillon, neurosurgeons at the Pierre Wertheimer hospital in Lyons, wrapped an electrode coil around the man’s vagus nerve, one of the main channels of communication between the abdomen and the base of the brain.
Powered by a battery in the left side of the chest, the machine delivered a 0.25 milliamp (mA) current of electricity to the nerve in 30-second bouts every five minutes.
The theory is that boosting the signals going up through this nerve gradually coaxes the bottom part of the brain into action, powering up an important region known as the thalamus, a lemon-sized chunk that acts as the “gateway” of the senses.
The electrical stimulus is supposed to flood this area with norepinephrine, the brain’s equivalent of adrenaline.
The first month went by and nothing changed. Each week the doctors increased the current by another 0.25mA until it reached 1.5mA. Slowly the patient’s situation improved as he rose into a flickering awareness of his surroundings. He began to move more naturally, to follow things and people moving around the bed with his gaze.
Using electrodes attached to the man’s scalp, the researchers, whose report appears in the journal Current Biology, saw an uptick in his theta waves, which are associated with the borders between sleep and wakefulness and are a classic marker of basic consciousness.
Joseph Fins, an expert on disorders of consciousness at Weill Cornell Medical College in New York, said the study was further evidence that many people who were effectively abandoned to unconsciousness could be rescued.
“The ideal technology would be non-invasive and enduring and come with no side-effects,” Professor Fins said. “Right now we have a proof of principle. It’s a promissory note.”
Angela Sirigu, of the Marc Jeannerod Cognitive Sciences Institute in Lyons, who led the study, said it showed that it was possible to “improve a patient’s presence in the world” with the relatively risk-free technique. “Brain plasticity and brain repair are still possible even when hope seems to have vanished,” she said.
A leading expert described the findings as a “promissory note” showing that many people who were dismissed as permanently unconscious still had latent cognitive potential that could be activated.
Bioelectronic medicine combines molecular medicine, bioengineering, and neuroscience to discover and develop nerve stimulating and sensing technologies to regulate biological processes and treat disease.
Much of the progress made in bioelectronic medicine has been driven by university research so far. But more than a year ago, the British drug company GlaxoSmithKline dove into the field and is now funding about 25 investigations exploring disease biology and neural signaling. They are betting that the budding discipline will lead to a whole new class of medicines for metabolic, immune-inflammatory, respiratory, cardiovascular and other disorders.
Photo: A brain computer chip
Others are also heavily invested in the future of bioelectronic science. A few start-ups are working toward clinical applications. The US National Institutes of Health is also advancing neuroscience with its Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative. But scientists still have to work out some major puzzles before they can benefit patients. For one, they have to completely map out which nerves affect which organs and functions. Once that base is built, the field could be well poised to fully take off.
As Joseph Fins has noted, at the very least, we have a promissory note.