GRENOBLE - Since 2009, a team of 30 researchers from the Clinatec biomedical platform of the French Alternative Energies And Atomic Energy Commission (CEA) has been tackling a huge challenge: allowing quadriplegics to walk and open a door thanks to a brain-controlled implant system.
For this to happen, the CEA is relying on different technologies that it is developing in-house, in the fields of neuroscience, software and robotics. The man behind the project – called BCI for “Brain Computer Interface” – is Doctor Alim-Louis Benabid, a world-renowned brain specialist and former head of the neurosurgery department at Grenoble University Teaching Hospital. In the 1990s, he developed a deep cerebral simulation technique for the treatment of Parkinson’s disease.
Benabid managed to convince the director of technological research at the CEA to create a research institute dedicated to neuroscience. He is also the one who decided that the institute’s first project should target mobility impairment.
“We wanted to start with a project that means something, that provides a clear benefit to patients,” explains Dr. Benabid. “We also wanted to use different kinds of cutting-edge technology: micro and nano-electronics, implantable devices, robotics.” We finally agreed on an exoskeleton piloted by the brain because “it allows the user to recover an almost natural mobility,” says the researcher. But also “because no one has been able to achieve this before.”
Thanks to progress in neuroscience and computer technology, research on controlling a machine using the brain has made huge strides in the past few years. About a year ago, researchers from Brown University, in the U.S., published an article in the scientific magazine Nature about a quadriplegic woman, Cathy Hutchinson, who was able to control a robotic arm thanks to a brain implant system called BrainGate.
The first step of the CEA project relies on a new kind of brain implant. While the 96 mini-electrodes of the BrainGate sensor are directly implanted in the brain, the French equivalent will be inserted on the surface of the motor cortex – the area in the brain responsible for voluntary movements.
“What makes brain control possible is that when we think of a movement, the electric activity within the motor cortex is the same as when we actually make the movement,” says CEA researcher and project coordinator Corinne Mestais. “So we will ask the patient to think about moving and measure the activity levels,” adds Guillaume Charvet, head of the team responsible for creating the implant.
The implant, called Wimagine, is a five-centimeter diameter electronic device that is powered wirelessly. It has 64 sensors that constantly record and broadcast electric activity. After encouraging tests on animals, the first human implantation could happen late 2013 or early 2014 – once the French National Safety Agency for Medicines and Health Products (ANSM) approves it.
The second part of the project is the interpretation of the data acquired by this new device. The challenge is to read very low-frequency electric signals (between 10 and 100 microvolts) and turn them into intended movements. A computer model is being developed by a different team, who are working on the premise that at some point, the researchers will have to manage two implants simultaneously – one for each hemisphere of the brain – that will control two limbs at the same time. This is a much more complex hypothesis than Brown University’s single robotic arm. Hence the importance of calibrating and studying the implant directly on the patient.
At the same time, researchers from CEA-List, which is also part of the Clinatec platform, is developing the third part of the equation – the exoskeleton itself, called EMY for “enhanced mobility.” The prototype weighs about 60 kilos and includes 20 motors, which are able to control the four limbs. “Our goal is to reach 35 kilos,” explains Alexandre Verney, a researcher at CEA-List. This exoskeleton requires several more years of development, especially to solve issues of safety, balance and autonomy. It shouldn’t be completely autonomous until 2020.
The different research teams working on the BCI project know that there is a long road ahead and that handicapped and mobility impaired people have very high expectations in this regard. Meeting these expectations with finesse and humility is also part of the challenge.