Next-gen artificial limbs help amputees grab onto a better life

With spindly metal fingers, carbon-fiber knuckles and black silicon fingertips, there’s no mistaking Albrich’s prosthetic left hand for its muscle-and-bone counterpart, but the things it can do certainly come close. He can grasp a water bottle and twist off the cap. Pick up a quarter off the table. Hold a tiny finishing nail while he pounds it in with a hammer. He can even view a graph of the electric signals he uses to trigger it … on an iPhone. Try doing that with the real thing.

Though he’s one of the first recipients in the United States to receive one, Adrian’s hand – an i-Limb Digits from a company called Touch Bionics – is part of a growing wave of next-gen prosthetics. Using some of the same advanced technologies that power modern smartphones, these electronic limbs are finally making it out of experimental labs, and changing the way amputees, live, work, and play in the real world.

Twenty-six years ago, at the age of 19, Albrich was working at a sawmill in the little Oregon town of Baker City when a log buckled in a conveyor belt and kicked him into an 18-inch chop saw. The blade chewed through his left hand like one of the area’s plentiful ponderosa pines.

He lost the hand just below the wrist, leaving Albrich’s hand with no fingers, but some remaining movement where his forearm ends – a “partial hand,” in the parlance of prosthetists.

“It could have been much worse,” he says, with the confident air of a man who has long since given up on feeling sorry for himself. An 18-inch saw, after all, can take a lot more than a hand.

Then he spotted the i-Limb Digits online, and Albrich decided it might be worth revisiting prosthetics. “The part that impressed me the most is that it was designed for someone with a partial hand, which no other prosthetic had been in the past,” Albrich says. No more pool cue.

After contacting a doctor in Seattle to see how he could go about getting his own Digits, Albrich ended up at Advanced Arm Dynamics, a Portland, Oregon clinic that specializes in prosthetics for upper extremities, including the advanced i-Limb Digits. Introduced a little more than a year ago, the bionic hand is still so new, the clinic speculates that fewer than 50 people in the United States have one.

Just as faster, smaller, more efficient processors allow our smartphones to get more powerful, more compact and run longer, the same advances are finding their way into active prosthetics. But the results are a lot more dramatic than being able to load Reddit two seconds faster, or snag an extra hour of video playback.

“Electric digits have been around for about 10 years, but the size of the fingers themselves, even over the past three years, has really improved to the point where we can fit them on a much larger percentage of the population,” says MacJulian Lang, the prosthetist who outfitted Albrich with his new hand. “The hand that he’s running, even 15 years ago, would have taken a backpack to run.” Now, ultra-efficient DC motors that move each finger fit right inside them, and the tiny processors and lithium-ion battery packs – similar to what you might find powering a smartphone – hide in a slim wrist strap.

The prosthesis locks onto Albrich’s partial hand with only suction, a clever approach that prevents the prosthesis from locking up his wrist. “Try picking a glass some time, but keeping your arm straight,” he explains. “You have to manipulate your entire body to get your hand where you want it.” The contortion is not only tiring – it can lead to other injuries, as different body parts get overused.

“The first half hour or 45 minutes, I didn’t think it was going to be possible,” Albrich says. “It’s kind of re-teaching my body how to operate a limb that hasn’t been there for so many years.”

Training himself to move his remaining muscles was only the beginning; he still needed to memorize what they did. Like the array of buttons on a Mortal Kombat arcade machine, different combinations of triggers can tell the hand’s microprocessor to pull different moves. For example, what seems like the same trigger might alternate between activating a two-fingered pinching grip you would use to pick up a pencil, and the full-hand grip you would use to grab a can of Coke.

After more than a month, Albrich still gets a few surprises. At one point in Lang’s office, his hand threw up a pair of devil horns as if he were at a Black Sabbath show. “I have no idea how I did that,” he says with a laugh.

Software helps manage the potentially confusing array of configurations. When the hand is connected to a computer via Bluetooth, Albrich can see a graph showing the signal from each of his myoelectric triggers tracing across the screen in real time, with a line representing the threshold he has to cross to spark a reaction from the hand. He can see the signal from each sensor as he flexes, train his muscles to better control them, adjust the thresholds to prevent accidental activation, and remap which triggers correspond to which grips. I-Digits even makes an iPhone app that Albrich could use to get the same data on the go. But as a diehard Android fan, he’s not interested. “Even my hand is not worth switching over to Apple,” says Albrich. He’s laughing, but it’s not a joke.

People still stop to watch when Aldrich ties his shoes one-handed – a feat that requires no electric digits, and a reminder that he can still get through life just fine without them. But Albrich says he’s still grateful for the doors his 21^st century hand has opened. “Doing something as simple as holding onto a potato to cut it, which I recently did, is just amazing.”

Almost every week, Albrich drives more than an hour from his home in Salem, Oregon to get further rehabilitation at Advanced Arm Dynamics – one of the few clinics that offers such extensive follow-up training for prosthetic users. “Every time that we do this, we’re figuring out new things that it can do,” he says, “or new ways that I can apply it to my everyday life.”

“I can manipulate something as delicate as a flower without crushing it,” Albrich adds. “But I can also put a grip on something [so strong] that you couldn’t pry it out of my hand.”

His favorite trick, though, is driving – if only for the shock value it elicits when other drivers cruise by and see a metal fist wrapped around the steering wheel in the car next to them. Though the i-Limb Digits can be wrapped in a silicon skin made to look more like a normal hand, Albrich prefers the utilitarian look of the unmasked components.

“It’s not a real hand. I don’t want the pretense of it trying to look like a real hand,” he says. Besides, the Terminator look has its own perks. “It’s a great conversation starter. I deal with people for a living, so it suits my needs.”

Although Albrich’s I-Limb Digits are on the cutting edge of commercially available prosthetics, they still have their limitations. Namely, sensation.

Without any feedback from the hand to his brain, Albrich’s only idea of how tightly he’s gripping something comes from visual and audio cues, like a water bottle crinkling under force. “It’s kind of like wearing a really thick glove: You have a basic idea of where you hand is and what it’s feeling.”

“My guess is within five years, there’s going to be clinically applicable ways to provide that sensation, that sense of touch, back into that feedback loop, so people have a knowledge of where their fingers are and what they’re doing,” says Lang. “It’s one of the things that makes upper-limb prosthetics in some ways frustrating but in some ways really exciting: We’re still just scratching the surface.”

Scratching the surface or not, Albrich remains continually impressed by what his humble electronic limb can do.

“This is really just a spectacular little tool,” he says, cradling the Digits. “I keep referring to it as a tool, but it’s more than that to the person that wears it. It’s just amazing what it can do.”