Bionic legs are at once a promise and a worry

Hugh Herr says he wants to eliminate disability. After 50 minutes listening to him speak at SXSW in Texas, it’s hard not to believe that he’ll do it. Herr is an impressive figure behind a podium; tall, imposing and with a well-cut suit that stops just below the knee. Below that, Herr is constructed of a pair of supremely impressive bionic legs.

Herr has a seductive backstory, which begins with prodigious talent as a young mountain climber. He was lucky to survive a traumatic accident on Mount Washington in January 1982, in which he suffered severe frostbite and had both legs amputated below the knee.

The same stamina and tenacity that made him an exceptional climber also made him dismiss the doctor’s verdict that he would never climb again, so his narrative goes.

Within weeks of having his first prostheses fitted, Herr was climbing again and in a workshop augmenting his very basic prostheses. He developed a bladed device that could wedge itself into smaller crevices than a human foot, welded a crampon(a metal plate with spikes fixed to a boot for walking on ice or rock climbing) to a prosthesis so that he could climb frozen routes up mountains, and even made prostheses much longer than his natural leg length, which meant he could reach holds able-bodied climbers couldn’t stretch to.

“At the beginning of that year society said I was broken. One year later I had surpassed my pre-amputation climbing abilities and done climbs no climber had ever done. I had augmented my body within 12 months, so much so that a few competitors were threatening to cut off their own legs.”

The audience watching Herr is already hushed and reverent, in awe of both his bravado and his achievement. And then he explains how much his work has moved on.

His team mapped how muscles and tendons work in the human leg, processes controlled through the spinal cord, and then programmed microprocessors to emulate those movements — subtle but critical “positive force feedback”, or contraction and expansion of muscles and tendons.

Put that computing power in a biomechatronic limb and the result is one that feels as good, or better, than a biological one. And lighter too —lighter than a graphite tennis racket.

The biggest problem, and huge financial cost, for many amputees is the cluster of secondary skeletal conditions that later develop, typically hip, back and knee problems caused by limping on traditional prosthetics. Herr’s argument about saving the cost of treating all these related conditions is slightly undermined by the fact that his own legs cost several million dollars in R&D resource.

Bionics will become so appealing that some people may choose to amputate just so that they can augment their bodies; our own legs might begin to feel heavy and stupid, he thinks. Given cosmetic surgery now, how would we feel about going under the knife for an arguably more justifiable benefit? This raises some intensely challenging issues about whether we will see a far more profound human digital divide, already hinted at in sci-fi countless times: the augmented, and the unaugmented.

In this view of the body as a biological machine, the parts that don’t work can be replaced, improved, remodelled.

The brain is extraordinarily complex, but its functionalities and specificities are being mapped. Eventually electronics, tapping the body’s neural network, will be able to override what we currently consider disabilities.

A colleague at Massachusetts Insititute of Technology, Ed Boyden, has already done exactly this with blindness. Boyden planted light-sensitive proteins on the faulty photoreceptors in the eyes of a blind mouse — effectively adding solar panels on to cells — and then switched them on. The blind mouse was no longer blind. It is rare to hear an audience gasp in amazement, but it happened here.

“We have to go beyond what nature intended, a future where technology and what it is to be human are blurred. A new nature that will give us new bodies and where disability is no more,” he said.

Depression, diabetes, paralysis, Parkinson’s disease, brain injuries, migraine, anxiety, tinnitus, sleep disorders, multiple sclerosis, schizophrenia — all these conditions could be eliminated, in Herr’s world. That is the promise.

But it is a promise dependent on huge resources and cost and on a centre of technological expertise that gives the West yet more advantage and privilege, a conversation a thousand times removed from the poverty and disadvantage of the developing world.

As Kerr says: “Remove technology and I am imprisoned. All I can do is crawl. But with it I am free.”