A man who spent 15 years in a vegetative state has shed tears for the first time following an electronic implant.
The 35-year-old, left severely brain damaged by a car crash, had shown minimal signs he was aware of the outside world following the accident.
But following an electrical stimulus to a nerve attached to his brain, he was able to smile and appeared to cry listening to a favourite song. For the first time, the unnamed patient was able to follow a moving object with his eyes and turn his head on request.
It had been believed someone in a vegetative state for more than a year could not regain consciousness. Scientists are now seeking to use the same technique on other patients to see if it could work more widely.
The 35-year-old, left severely brain damaged by a car crash, had shown minimal signs (left) he was aware of the outside world following the accident. But following an electrical stimulus to a nerve attached to his brain, he was able to smile (right: his brain scans three months after)
The breakthrough was seen following stimulation of the vagus nerve, which connects the brain to the rest of the body and is known to be important in waking and alertness.
Dr Angela Sirigu, a co-author of the study published in the journal Current Biology, said: ‘Brain plasticity and brain repair are still possible even when hope seems to have vanished.’
Dr Sirigu, from the University of Lyon, added: ‘It is possible to improve a patient’s presence in the world.’
Experts have urged caution
Experts have urged caution over the results, as the improvements are relatively small and have been seen in one patient only.
However nerve stimulation is said to be the first technique to make a difference to the 35-year-old, for whom drugs and rehabilitation were ineffective.
French researchers purposely chose a patient who had been in a vegetative state for more than a decade, implanting a vagus nerve stimulator implanted into his chest, which was switched on after a month.
For the first time, the unnamed patient was able to follow a moving object with his eyes and turn his head on request (pictured: information sharing across all electrodes before and after vagus nerve stimulation)
An electric current of 1.5 Milliamperes maximum, was applied to the vagus nerve, with the patient monitored over 20 sessions.
The treatment, used already in epilepsy and depression, increased the activity in his brain which showed up in scans. After one month of vagal nerve stimulation, the patient’s attention and movements also significantly improved.
When did he start to respond?
He began responding to simple orders that had been impossible before, following a moving mirror with his eyes and turning his head. His mother, who gave permission for the surgery to implant the nerve stimulating device, reported an improved ability to stay awake when listening to his therapist reading a book.
The researchers also saw responses to a ‘threat’ which had been absent. From being minimally conscious previously, he now widened his eyes in shock if a researcher’s face appeared suddenly in front of him.
The study states: ‘Meaningful affective behaviours have been also elicited in response to emotional stimuli. For instance, a smile on the left cheek and tears were observed while listening to his preferred music.’
‘An interesting new lead’
Dr Vladimir Litvak, senior lecturer at the Wellcome Centre for Human Neuroimaging, within UCL’s Institute of Neurology, said: ‘This might be an interesting new lead but I would suggest to be cautious about these results until they are reproduced in more patients.
‘It is hard to know based on a single case how likely this treatment is to work in the general patient population. Furthermore, a minimally conscious state still constitutes severe disability and the authors of the paper had to use special clinical tests and neuroimaging measures to prove that there has indeed been a change in the patient’s state.’
Dr David McGonigle, a neuroscientist at Cardiff University, added: ‘Evaluating the effectiveness of a treatment when you only have a single, albeit impressive, result is tricky, if not impossible. A full randomised controlled clinical trial is really needed to fully evaluate the effectiveness of vagal nerve stimulation in people in a vegetative state.’