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Work, health, military: is the augmented human revolution already here?

Reclaiming autonomy: the repaired human

Marina Julienne, Independent Journalist
On June 23rd, 2022 |
4 mins reading time
Reclaiming autonomy: the repaired human
Vance Bergeron
Vance Bergeron
CNRS Research Director and President of Association Advanced Neurorehabilitation Therapies (ANTS) at Ecole Normale Supérieure de Lyon, Physics Department
Grégoire Courtine
Grégoire Courtine
Professor of Neurosciences at the Ecole Polytechnique Fédérale de Lausanne (EPFL)
Key takeaways
  • Exoskeletons appear to be a good way of supporting an ageing population, as is the case in Japan for example.
  • In 2020, a team led by researcher Grégoire Courtine implanted three paralysed men with a cardiac neurostimulator in the abdomen, and about fifteen electrodes on their spinal cord.
  • The operated patients were able to take their first steps almost immediately but has only been carried out on a treadmill in the laboratory for the moment.
  • Many improvements are expected on these exoskeletons, including Bluetooth to get rid of wires but also a lower cost to make it more accessible to all.

Around twen­ty indi­vid­u­als are train­ing today in a rather unusu­al gym, on bicy­cles and sta­tion­ary row­ing machines. These peo­ple are spe­cial in that they are all liv­ing with a dis­abil­i­ty. Their legs and arms shouldn’t be able to move, but thanks to elec­tros­tim­u­la­tion, their mus­cles can now respond again.

Vance Berg­eron, direc­tor of research at the Physics Lab­o­ra­to­ry of the ENS in Lyon, him­self tetraplegic fol­low­ing a cycling acci­dent, is at the ori­gin of the S.P.O.R.T (Stim­u­lat­ing Peo­ple and Orga­niz­ing Recre­ation­al Ther­a­pies) room, cre­at­ed in 2018 by the asso­ci­a­tion ANTS (Advanced Neu­ro-reha­bil­i­ta­tion Ther­a­pies & Sports).

“The idea of elec­tri­cal­ly stim­u­lat­ing mus­cles is not new,” explains Vance Berg­eron. “In fact, it was a French­man, Dr Duchenne de Boulogne, who stud­ied the phys­i­ol­o­gy of move­ment using elec­tri­cal exper­i­ments in a book pub­lished in 1867 that has remained a ref­er­ence ever since! The devel­op­ment of exoskele­tons came lat­er, start­ing in the 1950s, but research in the field stag­nat­ed until the semi­con­duc­tor and elec­tron­ics boom of the 1990s.”

Efforts around the world

Japan is lead­ing the way in this area, with exoskele­tons seen as a good way to sup­port an age­ing pop­u­la­tion. The Unit­ed States, on the oth­er hand, is focus­ing on mil­i­tary appli­ca­tions. What remains is to com­bine the two tech­nolo­gies; exoskele­ton and elec­tri­cal stim­u­la­tion. This is what the com­pa­ny Cli­natec, found­ed in 2006 by Pro­fes­sor Alim-Louis Ben­abid, a neu­ro­sur­geon in Greno­ble, is doing. By design­ing an implantable device that col­lects the brain sig­nals emit­ted when a per­son intends to make a move­ment, the Cli­natec researchers hope to give tetraplegics the pos­si­bil­i­ty of men­tal­ly con­trol­ling an exoskele­ton robot to walk and manip­u­late objects.

Gré­goire Cour­tine, a neu­ro­sci­en­tist at the Ecole Poly­tech­nique Fédérale de Lau­sanne (EPFL), is also work­ing towards this goal and has just test­ed the pos­si­bil­i­ty of allow­ing tetraplegics to walk again using an abdomen-implant­ed car­diac neu­rostim­u­la­tor and spinal-cord-implant­ed elec­trodes (see box). These devices are very inva­sive, how­ev­er, and results still uncer­tain. Main­tain­ing phys­i­cal activ­i­ty in the dis­abled brings imme­di­ate ben­e­fits though and is safe. “Stim­u­lat­ing injured limbs effec­tive­ly com­bats the risk of sec­ondary com­pli­ca­tions that can arise fol­low­ing an injury to the spinal cord,” explains Vance Berg­eron, “whether it is caused by an acci­dent or a stroke.”

Fol­low­ing his acci­dent, Vance Berg­eron reori­ent­ed his laboratory’s activ­i­ty to devel­op an elec­tros­tim­u­la­tion bicy­cle. It works as fol­lows: the ped­alling move­ment is recre­at­ed via non-inva­sive sur­face elec­trodes, sim­ply placed on the legs of the paral­ysed per­son. An elec­tric cur­rent stim­u­lates the motor nerves to trig­ger mus­cle con­trac­tions in a sequence that allows them to ped­al again. “We thus pre­vent var­i­ous phys­i­cal risks, such as bed­sores, bone dem­iner­al­i­sa­tion and blood cir­cu­la­tion dis­or­ders,” con­tin­ues Vance Berg­eron. “Elec­tros­tim­u­la­tion also has a psy­cho­log­i­cal impact: main­tain­ing mus­cle vol­ume gives the per­son a bet­ter body image and makes dai­ly move­ments eas­i­er, espe­cial­ly trans­fers from the wheel­chair, which require con­sid­er­able phys­i­cal effort.”

Benefits for well-being

Final­ly, being in a place such as a gym makes social rein­te­gra­tion eas­i­er, reduces iso­la­tion and there­fore the risk of depres­sion. Two bicy­cles and a row­ing machine are now avail­able in the S.P.O.R.T room, which is still the only one of its kind in France. There is prob­lem with these elec­tros­tim­u­la­tion devices, how­ev­er, in that they cause sig­nif­i­cant mus­cle fatigue. “When a marathon run­ner trains, he uses dif­fer­ent mus­cles from those used by a sprint­er,” explains Vance Berg­eron. “In the lab­o­ra­to­ry we are try­ing to see how we can tar­get cer­tain mus­cles, and not stim­u­late them all at the same time.”

The lab­o­ra­to­ry is also work­ing on improv­ing the equip­ment, with a Blue­tooth sys­tem that would make it pos­si­ble to get rid of the wires by inte­grat­ing the elec­trodes into cloth­ing. Final­ly, the aim is to offer finan­cial­ly com­pet­i­tive equip­ment. “The first bike designed for elec­tros­tim­u­la­tion that I import­ed from the US and adapt­ed it so that it could be used in France cost €30,000! Now I’m work­ing with a Ger­man com­pa­ny1 on a mod­el that is acces­si­ble to the pub­lic, at around €2,000.”

What equip­ment will be used by dis­abled peo­ple in the future? Exoskele­tons cer­tain­ly allow peo­ple to stand up, but even in their non-inva­sive ver­sion, they are very heavy, and their oper­at­ing-time is lim­it­ed by bat­tery life. In com­par­i­son, elec­tros­tim­u­la­tion is very sim­ple: a few watts are enough to make the device work…

Making tetraplegics walk again?

In 2020, a team led by researcher Gré­goire Cour­tine, a neu­ro­sci­en­tist and pro­fes­sor at the École Poly­tech­nique Fédérale de Lau­sanne, Joce­lyne Bloch, a neu­ro­sur­geon at the Cen­tre Hos­pi­tal­ier Uni­ver­si­taire Vau­dois (Switzer­land), and Guil­laume Charvet; project leader at CEA-Leti Cli­natec (Greno­ble), used abdomen-implant­ed car­diac neu­rostim­u­la­tors in three paral­ysed men and spinal-cord-implant­ed elec­trodes to tar­get acti­va­tion regions in the trunk and leg mus­cles. The patients were able to take their first steps almost imme­di­ate­ly, even though walk­ing on a lab­o­ra­to­ry tread­mill is not exact­ly the same as nor­mal walking.

In con­crete terms, the tech­nol­o­gy requires at least six cen­time­tres of healthy spinal cord under the lesion, where the elec­trodes are implant­ed. The patient has a walk­er with two but­tons attached. He has to press the right but­ton if he intends to lift his left leg; and the left but­ton if he wants to lift his right leg. 

These but­tons are con­nect­ed to a tablet, which con­tains the con­trol soft­ware that trans­mits sig­nals to the neu­rostim­u­la­tor. The neu­rostim­u­la­tor in turn relays these sig­nals to the spinal implants, which then acti­vate the spe­cif­ic neu­rons that con­trol leg lifting.

After five months of reha­bil­i­ta­tion, one of the patients, for exam­ple, was able to walk almost a kilo­me­tre with­out stop­ping. As soon as it is switched off, how­ev­er, the elec­tri­cal stim­u­la­tion has no effect. It can­not be main­tained per­ma­nent­ly though because doing so would exhaust patients.

This tech­nol­o­gy will be the sub­ject of exten­sive clin­i­cal tri­als, led by the Dutch start-up Onward.

1Sen­sorStim Neu­rotech­nol­o­gy GmbH