CRT Technology Showcase

Next-Generation SmartDrive Seeks Next Generation of Users

SmartDriveEverybody loves a winner. And that was a good description for MAX Mobility’s first SmartDrive power-assist system, the MX1. It was a compact two-piece wonder consisting of a battery pack and a motor. Attach them to a manual chair, and the MX1 could be activated on demand to assist consumers, particularly in tough propulsion environments such as thick carpeting, hills or ramps. The MX1 reduced the number of strokes that self-propellers had to make, thus lowering their exertion, but put the chair user firmly in command of when to use or not use the device.

The MX1 was so efficient that it found fans among wheelchair users who hadn’t originally been in the device’s target demographic. In a case of success breeding success, that led to some interesting issues.

Seeking to Stop Shoulder Pain

Mark Richter, who has a Ph.D. in mechanical engineering from Stanford University, is president of MAX Mobility. Richter has long been interested in wheelchair users who self propel — and in particular, interested in the challenges they face throughout their lives, including shoulder injuries from years of propulsion.

“Almost three out of four manual chair users have shoulder pain already,” Richter says. “It’s really at an epidemic level. If 60 to 80 percent of able-bodied people had the same condition, it would be on CNN every night.”

With a grant from the National Institutes of Health, Richter studied how self-propellers pushed their wheelchairs. In addition to looking at their biomechanics, he studied the efficiency of wheelchair setup and the use of ergonomic accessories, such as pushrims that supported greater efficiency. And they worked.

“Maybe I got 30 percent improvement in efficiency if you combine all those things, which I thought was amazing,” Richter says. “But it turns out that’s like having shoulder pain in 13 years instead of 10. It’s really not enough. I want 40 years of shoulder life, if not more.”

That’s when Richter realized he needed a completely different kind of solution — a motorized one. And the MX1 fit the bill. Users pressed a chair-mounted button to activate SmartDrive, pushed on the rims to go, and pressed the button to stop (since pressing the button turned the motor off).

Richter’s target user demographic for the MX1 was the selfpropelling chair user with paraplegia, because shoulder pain is so common with that population, and shoulder pain was what Richter was ultimately trying to prevent. He now says he “assumed it was obvious” that the MX1 was truly aimed at paras. But a funny thing happened along the way.

“Because it was so small and kind of cool looking, everybody wanted to use it,” he says. “And ‘everybody’ wasn’t who I was planning on.”

Consumers with quadriplegia were among the MX1’s avid fans, despite the MX1 being “not at all quad friendly,” Richter says. Clinicians said their clients with quadriplegia didn’t have enough gripping strength to effectively brake MX1-equipped chairs. So Richter set out to design a device that could be used by a much wider audience. He says a second version of the SmartDrive was “a step in the right direction,” but not exactly right. So he kept working and created MAX Mobility’s latest launch: the MX2.

How the Apple Watch Helped the MX2

The MX2 is not merely an MX1 upgrade with a few bells and whistles added. It’s a new creation unto itself.

For instance, there’s no separate battery pack for the MX2; everything is now incorporated into the motor system that attaches to the wheelchair. And the MX1’s press-the-button activation and deactivation methods are gone, too.

“Luckily I’ve got access to some really great engineers, so I can play with some of the latest and greatest technologies,” Richter says. “One thing we’ve always known about was the use of accelerometers.”

Accelerometers are “the kind of sensors that are in your cell phone that navigate and do orientation,” he adds. “We have those same things already in the SmartDrive. And we know if you put one of those on your wrist, you can detect motion and resolve different types of functions. That’s the kind of thing [Apple’s] iPhone uses for the Apple Watch, for turning the screen on and turning the screen off.”

What the MAX Mobility team has created in the MX2 is essentially hands-free operation — because, as Richter points out, wheelchair users’ hands are typically pretty busy already.

“The idea was that we could create a more intuitive interface, so more people could use it, and it would be easier for them to use,” Richter says. “So we set off on this quest to try to create a better system basically to access the motor.”

SmartDriveRemember that the MX1 required precise physical input: Pressing a button to turn the motor on, pushing the pushrim to go (and pushing again if you wanted to go faster), pushing the button to turn the motor off.

On the MX2, the buttons that were mounted on either side of the chair have been replaced by a single wristband worn by the wheelchair user. That wristband communicates via Bluetooth with the SmartDrive system. The chair user presses a button on the wristband to activate the unit, then pushes on the pushrim to go. To brake, the user taps on the pushrim — a light pat will work — to stop the motor, then holds the pushrim in a normal braking motion. The user no longer has to find and press a button on the side of the chair to disengage the SmartDrive motor.

When the user doesn’t want to use SmartDrive — such as in tight spaces — a press of the wristband deactivates the unit. Tapping lightly on the pushrim with a hand requires less finemotor control than was needed before, when the user had to locate and press a rather small button with a fingertip to disengage the motor. Richter says this new control method makes the MX2 much friendlier to use for people with quadriplegia.

“You push how fast you want to go, and it will continue to go there until you lightly tap on the rim to tell it to stop. And that shuts off the motion,” Richter says.

Indications & Contraindications

As with any complex rehab technology device, the MX2, as advanced as it is, won’t be the perfect solution for every seating & wheeled mobility client.

As an example, clients with excessive involuntary arm movements might have some trouble effectively communicating with the MX2.

“I’ve seen at least one or two cases of users that have such extreme arm motion during normal propulsion that it acts almost like a tap and shuts off the motor prematurely,” Richter says. “So I’m still experimenting with different locations that they could wear the band, like around the elbow.”

If that’s impossible, Richter is open to working out solutions for clients based on specific needs. Generally speaking, MAX Mobility is no longer offering the MX1’s design. But Richter says the MX1’s functionality still exists, so clinicians and ATPs with special requests should contact MAX Mobility to see what can be done.

Meanwhile, the MAX Mobility team is already working on improving the look of the MX2 band, which on first glance currently resembles a Fitbit band.

Convincing people to adopt a “wearable” system like the MX2 took some time, Richter says, adding that the growing popularity of the Apple Watch helped that trend along.

“I thought about wearables about a year ago, but before the [Apple Watch] buzz, people were almost phobic,” he says. “Now you have smart watches that are starting to become more accepted. Suddenly it’s not so big a deal, but we’re still in that transition people where some people are saying, ‘I don’t wear a watch.’ I want them to wear this because it’s so much better than a button. It’s so much safer, it’s so much simpler, it’s so much more intuitive. And once they’ll do it, they’ll love it. But until they do it, there’s this little apprehension toward wearing something.”

Richter says there’s also been progress in the perception of power-assist devices themselves. In years past, power assist was seen as something of a last resort to be used by long-time manual chair users whose shoulders and arms had already started to give out. Richter says that perspective is changing, thanks largely to a younger generation of users and evolving thought among clinicians.

“I think we’ve finally reached that point where — like the ergonomic rims of five or six years ago — it has sort of been engrained in therapists’ minds that it’s important to preserve the shoulders. So the stage has been set, and the magnitude of the change that’s possible with a SmartDrive versus [an ergonomic] pushrim is quite a bit more evident now. Once you see it, this is obviously a solution to what is a known problem.”

Funding sources still commonly think of power assist as a reactive rather than a proactive solution, but Richter says more and more users are considering power assist in a proactive way.

“What’s amazing about younger people in chairs: They don’t seem to have that same stigma, that whole ‘Use it or lose it’ mentality,” Richter says. “They just adopt new technology, like ‘It’s an aid for my life, like having a smartphone instead of having a laptop all the time or always being tethered to my e-mail at home.’ They don’t see it as a crutch; they see it as an enabling technology. They can do more, they can go farther, they can be happier in their lives.”

Richter points out that SmartDrive is already being used by “legacy” wheelchair users, so he’d love to also see the MX2 adopted by younger ultralight users as well as other populations such as foot-propellers and clients with hemiplegia.

“The new mantra is ‘Use it, don’t abuse it,’” he says. “Pushing is really not your best form of exercise. Our goal is if you’re using a chair, SmartDrive makes life better.”

This article originally appeared in the October 2015 issue of Mobility Management.

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