A high school teacher in a black coat enters the classroom. “Good morning,” he says to the students before starting his lecture, with his right hand busily scribbling something on a blackboard and his left holding a physics textbook.

Then, while holding the chalk and the textbook, he points at a female student and asks a question. The student answers.

“OK, that’s correct,” he says, giving her the OK sign with his third hand.

A third hand?

The 28-second YouTube video, titled “Three-handed Sensei,” was created by Tokyo-based prosthetics venture Meltin MMI Co. It epitomizes a future envisioned by its 29-year-old CEO, Masahiro Kasuya, where not only amputees but also able-bodied people can wear artificial limbs to boost their physical capabilities.

“If someone who has only one hand gets an artificial hand as an extension of the body, why can’t people with two hands add a third hand?” he said in an interview last week at his office in Tokyo’s Shibuya district. “The video presents such a scenario in a somewhat joking way, but I’m dead serious about realizing it.”

Kasuya develops prosthetic hands that move intuitively in response to bioelectric signals, subtle charges released by the muscles when people move their limbs.

Kasuya joined the venture set up by Hiroshi Yokoi, his professor at the University of Electro-Communications in Tokyo, in 2013 while he was still in the doctorate program. He became the CEO in February.

Kasuya, who received a Ph.D. in engineering, said he has always loved all things mechanical and robotic. One of his primitive but ingenious childhood inventions was a device that closes a window automatically in the middle of the night. He filled a plastic bottle with water and tied it to a window frame. Then he attached the bottle to a timer salvaged from a broken air fan. When the timer reached zero, the bottle would be dislodged and fall, shutting the window.

“I knew I wanted to be a robotics engineer from early on,” he said.

Kasuya’s interest in making a “brain-machine interface” also comes from his childhood.

In school, he said he was often bullied for being different. His teachers did not like him, either, because, being a child prodigy who excelled at math and physics, he often spotted their mistakes and challenged them in front of other students.

As a child, Kasuya often felt that words alone could not quite convey his pain of being bullied and ostracized, he said, adding that he wondered if there was a more intuitive, nonverbal way to convey it.

“When you put your experience into words, you lose a lot of crucial information in the process,” he said. “You can describe the pain you felt by saying, ‘It’s as painful as hitting a sharp object with your pinkie,’ but if the person you are talking to had never hit a sharp object with his or her pinkie, that person would never understand how it really feels.”

One day, he saw a TV program about cyborg engineering and its implications on surgical robots and prosthetic hands, and was immediately fascinated, he recalls, because he felt that this particular area of technology addressed his desire to relay human experiences more accurately and nonverbally, such as through brain waves and other biological signals.

Today, Kasuya’s research is crystallized in two technologies: software to analyze bioelectric signals, and robotic hands that respond to such signals as collected from sensors attached to the arm to replicate real hand movements.

Research into electromyography — or the electrical recording of muscle activity — has a history of more than 50 years and has made significant progress recently.

But his company, Meltin MMI, has a competitive advantage over other firms, Kasuya argues, with cutting-edge technology that can analyze the subtle differences in waveforms that show up in electromyograms and interpret what they mean in terms of human hand moves.

“Through our algorithm, we can identify the waveform for each of the rock-paper-scissors gestures,” he said, referring to the game, adding that few other firms have achieved this.

The firm’s robotic hand, meanwhile, is controlled by 36 wires connected to a motor box. Kasuya demonstrated these technologies by attaching three electrodes to his right arm and moving his right hand in various directions. The sensors picked up Kasuya’s muscle signals, which were immediately transmitted to his PC and made the prosthetic hand move naturally in sync with his hand and with no time lag.

The prosthetic is covered with an extremely elastic rubber glove that has fine wrinkles and nail shapes printed on it so it feels like real human skin. When I shook the robotic hand, it felt as though I was shaking the delicate hand of a woman with thin, long fingers, not just because of the high-tech glove but also because I could feel the robot’s subtle pressure changes on my palm.

Kasuya’s expertise has tremendous potential to improve the quality of life of people with disabilities. He has participated in a project for people with amyotrophic lateral sclerosis (ALS), a progressive neurodegenerative disease, to help them manipulate objects remotely by moving facial muscles.

Last October, he entered Cybathlon 2016, the first international competition for robotics technologies designed for people with disabilities, in Switzerland. His team was one of only three participating from Japan.

But the technologies’ applications will be limited if their only users are amputees.

Kasuya said there are currently three types of prosthetic hands on the market. The most popular type is “decorative prosthetics” — the hard, mannequin models that don’t move.

Myoelectric prosthetics are expensive — ranging from ¥1 million to several tens of millions of yen each — and they are not covered by the public health care system or government subsidies. Only a few dozen are in use in Japan, Kasuya said.

The firm is therefore trying to market bioelectric signal sensors to a larger group of people to explore their use as wearable health monitors. A joint project with doctors is already underway, but it will take at least a few years for such a device to clear regulatory hurdles and become commercially available, he said.

Kasuya’s lofty ambitions to remove physical barriers for all people remain intact, however.

“My ultimate goal is to create a society where anyone with a brain can live the life they want to,” he said.

“Right now, I’m focusing on electromyography and robot arms, but eventually, I want to develop technologies that can read all biosignals, including brain waves. If this is achieved, we can create robots that are controlled by bedridden people to care for themselves.”

“Maybe such people can go out after the care is given,” he added, grinning. “Of course it’s the robotic versions of them that go out, but they would feel like they are going out themselves.”

Key events in Kasuya’s life

1988 Born in Iruma, Saitama Prefecture
2010 Graduates from Waseda University’s faculty of science and engineering
2012 Obtains a master’s degree in engineering at Waseda University, enters a doctoral program at the University of Electro-Communications
2013 Joins Meltin MMI
2014 Becomes the venture’s chief operating officer
2016 Obtains a doctoral degree, participates in Cybathlon 2016, the first international competition of robotic technologies for people with disabilities
2017 Becomes CEO of Meltin MMI

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