This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
ASPEN. Life can change in an instant. We all know this, but we forget, or try to forget, this fact—until something happens that makes it hard to ignore.
An attractive blonde in a bright red blouse sits in a wheelchair before the assembled scientists, doctors, writers and members of the community. We are in a conference room at the Aspen Meadows Resort, the site of the 2013 Aspen Brain Forum. Amanda Boxtel recalls what life was like for her at 24. She had been a skier, a runner and a ballet dancer, she tells us. She liked to hike in the wilderness. Pictures of a beautiful young woman appear on a screen. In the photos, she’s standing. Then one day on a slope, the tips of Boxtel’s skis crossed. She did a somersault and shattered four vertebrae.
“I also shattered illusions of my immortality. I was paralyzed from here”—she hold her hands at her hips—“down. No movement and no sensation.” That life changed radically for her right then is difficult to dispute. But Boxtel eventually embraced a road to recovery. “It took time to turn wounds into wisdom. It took guts. This is a cruel injury. It is so much more than not being able to walk,” she tells us.
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With the aid of adaptive technology, she got back on her skis. She took up waterskiing, rock climbing, kayaking and hang gliding. But still, she couldn’t bear weight on her legs or walk. Walking seems easy to most of us, because the action is built-in; it is automatic. In reality, however, walking is a highly complex motion involving many different muscles that must contract in a precisely timed sequence. Once the spinal cord can no longer orchestrate this motion, it is exceedingly hard to replicate. Walking, for Boxtel, was arguably a pipe dream.
And so she sat for 21 years.
Yet, just in case, Boxtel exercised and stretched, using one therapy and then another and then a third. “I tried to keep my body supple so that one day my legs might support me again,” she said.
One day in 2010, she got a phone call from the then-CEO, Eythor Bender, of Berkeley Bionics, an engineering firm founded five years before in Berkeley, California, and company cofounder Nathan Harding. They asked her to travel from her home in Aspen to Berkeley to try out a bionic suit that might help her realize her dream. “It was exactly as I imagined,” Boxtel later told me, “so of course I’d say yes.”
The latest version of this suit, a 50-pound black robotic exoskeleton called the Ekso, is at the front of the room. Harding, a mechanical engineer who is now CEO of the renamed firm, Ekso Bionics, is here to help us understand the technology.
The goal, Harding tells us, is to get paraplegics up and walking over ground with a natural gait, bearing their own weight. Existing unpowered orthotics, which consist of essentially a leg brace that extends all the way to the waist, are cumbersome, extremely labor intensive, and cannot support a normal walking motion. A user grabs onto a walker and, keeping her legs stiff, swings them both forward simultaneously using the waist and trunk, a motion that requires heavy use of the chest muscles. The Ekso, by contrast, is designed to enable a reciprocal gait—left leg, right arm and vice versa—with bent knees and heel strikes.
The robot contains a computer brain with two attached battery packs on either side that a patient wears on her back. It also sports four motors—two at the knees and two near the hips—to power a person’s steps, and straps that secure the device at the shoulder, chest and legs. Two other straps attach each foot to its platform, a kind of shoe that is in contact with the ground.
As we look on, a physical therapist secures the various straps to Boxtel while she sits in a chair. Then, hands grasping walking poles, Boxtel pushes herself up to a standing position. In a moment, music begins to play and the audience stares in amazement, as Boxtel walks down the aisle that separates the conference attendees. She’s stepping naturally, if not rapidly, lifting her legs and bending her knees with each step—and smiling.
“I suffer from edema (swelling) and every day I walk in this device, edema goes down,” we hear her say. She goes to the bathroom more often and sleeps better. The device also relieves pain. “I have this incredible neuropathic pain,” Boxtel reveals. “When I walk in this device, my pain disappears completely.”
The whirr of machinery is audible, but deceptive, as is, to some extent, Boxtel’s grin. It turns out Boxtel is working hard, too. She has some hip flexor movement. But all of her leg muscles are severely atrophied. “It is exhausting just walking up and down the aisle. I get out of breath and my heart gets going,” she says. Yet Boxtel does seem to enjoy the workout—in part because it might be helping to rebuild her body. The exercise enhances her muscle power as well as rewiring some of her disabled neuronal pathways. Proprioceptive feedback from the weight-bearing motion may enliven sensory neurons while motor neurons learn to create the walking motion. “To walk in the robot, I had to retrain my body and my brain. I had to consciously think, ‘right arm, left leg and left arm right leg,’” Boxtel told me.
The robot includes sophisticated software designed to mimic the control the spinal cord once had. It triggers the first step as soon as Boxtel shifts her hips forward and to one side. Then the robot knows not to initiate another one until she’s shifted her weight the other way. It also uses a learning algorithm over a series of steps to figure out how much and what type of assistance is needed. Boxtel can increase or decrease the amount of assistance she gets. She can dial it down when she wants a workout, or ratchet it up when she prefers to parade effortlessly, say, around a party.
But Boxtel is not wearing the walker to parties yet. The device first began making its way into rehabilitation centers in February 2012, and so far 1500 patients have sported it, all getting up on their feet again for the first time since their disabling event. But with the exception of Boxtel, users only amble inside a facility. Boxtel takes it outside for a spin—in the parking lot of the rehab center, five days a week, trained therapist in tow. The therapist is a critical companion, as walking in this contraption is highly sensitive to small perturbations. When she walked down the aisle of the conference room, for example, the therapist moved the straps of my pack, which I had carelessly let drape into the passageway. Few parties could be so meticulously groomed of obstacles.
The exoskeleton is not just physically, but also psychologically, elevating. Standing up means patients can look others in the eye instead of the world looking down upon them. “I like the role reversal,” Boxtel announces. “All of you are sitting down while I am standing up.” A woman who exudes emotional warmth, Boxtel takes the opportunity to give Harding a hug. “I enjoy the psychological benefits of being tall and at eye level,” Boxtel said to me.
As the first individual in the U.S. to own this upgraded robot, Boxtel hopes to bring more exoskeletons, at a cost of $110,000 a piece, to individuals through her foundation Bridging Bionics. And she is looking forward to the day when she can use it in her home regularly, skirting obstacles, ascending inclines and climbing stairs. Software under development for the robot should eventually enable most of that, Harding says. Meanwhile, Boxtel is thrilled to be able to walk at all. Quality of life, she says, means relief from pain, swelling and sleeplessness, among other discomforts. That much, she says, is already a huge step forward.