2023-11-06 16:30:51
“Now, (…) I can walk from one point to another without worrying about how I’m going to get there“, summarizes this French patient, Marc, 62 years old, to AFP. “I can go for a walk, go shopping alone. Go do what I want.“
This sixty-year-old, who does not wish to give his last name, has been suffering from Parkinson’s disease for around thirty years, at a very advanced stage. He was no longer able to walk except with great difficulty.
This is the case for almost all patients when the disease has progressed significantly. They are particularly affected by “freezing“, a sudden blockage which often causes a fall. We hardly know how to treat these symptoms which end up seriously handicapping patients, ultimately condemned to remain bedridden or in a wheelchair.
Marc’s case is therefore exceptional and the result of a medical feat, detailed this Monday in the magazine Nature Medicine. A Swiss team of researchers implanted a complex system of electrodes, a “neuroprothèse“, on the spinal cord.
Result: this neuroprosthesis “reduced walking disorders, balance problems and freezing“, summarizes this work supervised by surgeon Jocelyne Bloch and neuroscientist Grégoire Courtine at the CHUV in Lausanne, with the support of the Federal Polytechnic School. The duo is already known for one of the great medical exploits of recent years: their team made several paraplegics who had previously been deprived of any leg movement following accidents walk again.
Electrodes are placed at crucial points in the spinal cord
This time, they are tackling Parkinson’s disease in collaboration with a third man, a specialist in this pathology: the neurobiogist Erwan Bézard, researcher at Inserm, who first tested this prosthesis for several years on monkeys. The principle is the same as for paralytics. Electrodes are placed at crucial points in the spinal cord to override the action of the brain.
In the case of the paralytics, their accident had interrupted contact between the brain and part of the spinal cord. In patient Marc and Parkinson’s patients in general, this contact still exists but it is the brain itself which functions poorly due to the progressive disappearance of the neurons generating a neurotransmitter, dopamine.
To work, Professors Bloch and Courtine’s system must therefore not simply send electrical stimulations. It must be able to assume the role of the brain by generating these stimulations at the right time so that the movement corresponds to the patient’s intentions.
“The idea is that we will measure the residual movements, therefore the intention of walking, with small sensors which are located on the legs“, explained Grégoire Courtine to AFP. “Thanks to this, we know if the person wants to do an oscillation phase or stop, and we will therefore adjust the stimulation accordingly.“
“Tour de force”
At Marc, the result is there. The patient has largely regained the normal use of walking, even if this requires great concentration. But, beyond that, can we already talk about a medical revolution that would benefit many Parkinson’s patients?
It is impossible to tell from a single patient, especially since the manifestations of the disease can be very variable. The team of Ms. Bloch and Mr. Courtine will therefore continue the experiment on a group of six Parkinson’s patients.
It also remains to be seen whether such an innovation, probably at a very high cost, will be able to benefit the greatest number of people, while the two scientists have launched a startup – Onward – to work on its commercialization. To justify public reimbursement, the therapeutic advance must be confirmed as major.
But Marc’s case already constitutes a “feat of strength“which demonstrates”feasibility” of such an approach, according to other neurologists who commented on the study in the same issue of Nature Medicine.
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