From perception and analysis to actuation, many robotics technologies have applications in healthcare, particularly in prosthetics and assistive systems. Myomo Inc.’s MyoPro is a wearable brace that uses sensors and algorithms to restore mobility to users.

More than 3 million people in the U.S. have lost control over their arms and hands because of stroke, brachial plexus injury (BPI), cerebral palsy, or other neuromuscular diseases or injuries.

“After six months of rehab, many patients are essentially told that they won’t be able to use that arm again,” said Paul R. Gudonis, CEO of Myomo. “That’s 1% of the population, or 3 million people in the U.S.”

Developing ‘power steering’ for the arm

Cambridge, Mass.-based Myomo is based on technology developed at the Massachusetts Institute of Technology and Harvard Medical School.

“A dozen years ago, we spun out of MIT,” Gudonis told The Robot Report. “Dr. Woodie Flowers was a pioneer in powered prosthetics, and his lab originally focused on amputees. However, a pair of grad students said there was a much larger group of people who could be helped.”

Myomo uses sensors built into a cuff that fits over the bicep and tricep muscles. They detect electromyographic (EMG) signals and activate motors to move the arm at the elbow.

“Unlike implants in the brain, which are still experimental, electromyogram sensors sit in a device on the surface of the skin,” said Gudonis. “In able-bodied individuals, the muscle emits voltage when activated, and there’s 100% signal strength, but after a stroke or other injury, the signals are attenuated.”

“The myoelectric orthosis, or powered arm brace, detects the intention to move as the muscle sends a micro EMG signal,” he explained. “Onboard software deciphers it, providing power steering for the arm.”

“The control unit on the side of the brace has the battery and a circuit board and sends control signals to two motors at the elbow and hand,” Gudonis said.

Myomo’s technology can be liberating for people using it, according to Myomo. “People can feed themselves, open doors, and carry objects,” said Gudonis.

Myomo makes software, hardware refinements

There have been several improvements over time, Gudonis said. “First is the refinement of the software algorithms and electromechanical interface,” he said.

“Second, taking our original design and making it a lightweight — 2.5 to 3 lb. — custom-fabricated orthosis or brace,” said Gudonis. “This takes it out of the clinic or rehabilitation hospital, and it can be used in the home or office.”

“Every few years, we bring out a new revision,” he said. “MyoPro 2 has the added ability to open and close hands. It has four sensors, on the bicep, tricep, flexor, and extensor, and it connects to a mobile app with Bluetooth.”

“We’re working on finer motor controls and lighter weight.” said Gudonis. “We use small motors from Maxon, and the battery is designed to be used all day. It can pop out, and we provide a spare battery.”

A major hurdle for healthcare robotics and devices in the U.S. has been reimbursement by insurance providers. Myomo is working with healthcare service providers.

“Our device is provided through orthotics and prosthetics clinics and billed to insurers,” Gudonis said. “The out-of-pocket price to the user depends on the his or her insurance plan, and it may be just a few thousand dollars.”

Reaching and training users

“This is really disruptive technology in the rehabilitation industry,” Gudonis claimed. “Prior solutions have been hands-on therapy at the hospital or big stationary machines in clinics, but nothing portable that people can use at home.”

“We’re using online advertising to inform 3 million people that there’s something for them,” said Gudonis. “We’re inviting them to free screening days, where they can be evaluated by a medical professional, and we can help them get reimbursed.”

“When people try on the demo device, they either laugh or cry,” he said. “One user was a veteran who was injured at 25. In 40 years, it was the first time he could use that arm. Another was an 18-year-old in Milwaukee who suffered a BPI at birth and hadn’t used her right arm since then. She’s now using both arms.”

Users then go to local therapists to be trained in how to use Myomo’s devices, and the therapists themselves need training.

“After users get insurance authorization, they place an order, and the local orthotist measures the arm and hand,” Gudonis said. “Like with prosthetics, they send an order to us for custom fabrication. We use a shop in Ohio, and lightweight plastic elements fit over the robotic elements, like a custom ski boot.”

“We have a training staff consisting of certified prosthetists, orthotists, and occupational therapists,” he said. “They train clinicians on how to evaluate patients, as well as work with occupational therapists at rehab hospitals around the country.”

“The software settings can be adjusted by the clinician,” noted Gudonis. “As muscles are used over time, the nerve signals can get stronger and need less amplification. We can adjust the gain applied to each joint of the arm. In other cases, such as ALS [amyotrophic lateral sclerosis], signals can decrease over time, but Myomo can help users remain functionally independent.”

Adding capabilities

Myomo is working on a pediatric version of the MyoPro 2. “It’s currently registered with the FDA for adults and adolescents,” Gudonis explained. “But millions of children are affected by conditions like stroke, cerebral palsy, birth brachial plexus injuries, spinal muscular atrophy, and AFM [acute flaccid myelitis], which is like polio.”

To work with children, Myomo’s device must be lighter, expandable, and “pass the sandbox test,” he said, adding that the MyoPro is water resistant: “Users can wash dishes, but they shouldn’t go swimming or take a shower with it on.”

“We’re working with Boston Children’s Hospital, Philadelphia Children’s Hospital, and Easter Seals,” said Gudonis. “Some of these improvements in terms of lighter weight and algorithmic changes will eventually apply to MyoPro 3.”

Myomo scales up

Myomo went public in June 2017 and has raised $25 million in the public capital markets.

“We’ve outsourced manufacturing of some robotics components to Cogmedix in Worcester, Mass., and a fabrication company in Cleveland,” Gudonis said. “We’re also talking to other custom fabrication shops in the U.S. and Europe to have sufficient capacity.”

“We were just doing controlled rollouts in just a few markets, and we’re now really scaling up commercial rollouts to the top 50 metropolitan service areas in the U.S.” said Gudonis. “We’re registered with the FDA and have a medical device license in Canada and a CE mark in Europe.”

“For lower-extremity paralysis, there have been a number of solutions, such as exoskeletons from ReWalk, Ekso Bionics, and Indego from Parker Hannifin,” he said. “But for upper extremities, we offer the only commercially available product, protected with 21 patents in the U.S., Japan, and Europe.”

“Almost 900 devices are in use, and we’re growing strongly now,” Gudonis said. “Myomo built out its nationwide distribution in the past year, and we have our first distributors in Europe, Chile, and Australia. Our goal is to be in all major regional markets by the end of this year.”