Tag Archives: bionic hand

Inflatable prosthetic hand is controlled by thought alone

Modern prosthetics can have a wide range of motion and enable users to control them through residual muscle signals to perform desired motions by thought alone. Once in the realm of science fiction, these bionic limbs show that the future is already here — for those who can afford it.

In an effort to make a limb prosthetic that is both highly functional and accessible, researchers at MIT and Shanghai Jiao Tong University have devised an inflatable neuroprosthetic hand that allows users to perform highly complex motions such as pouring juice from a container or zipping a suitcase. While similar neuroprosthetics cost upwards of $100,000, this inflatable hand can be made as cheap as $500.

“This is not a product yet, but the performance is already similar or superior to existing neuroprosthetics, which we’re excited about,” says Xuanhe Zhao, professor of mechanical engineering and of civil and environmental engineering at MIT. “There’s huge potential to make this soft prosthetic very low cost, for low-income families who have suffered from amputation.”

The squishy prosthetic is made from a soft, stretchy material — an elastomer known as EcoFlex. The soft and elastic properties allow the prosthetic to be both lightweight at just half a pound (225 grams) and very durable, with tests showing it can recover its original shape after being squashed by a hammer or run over by a car.

Each of the five balloon-like fingers wraps around segments of fiber that act in lieu of articulated bones. These digits are connected to a “palm” that was 3-D printed in the shape of an actual human hand. Rather than using complicated and heavy electric motors, the fingers are articulated using a pneumatic system consisting of a small pump and many valves that has to be worn around the waist.

A volunteer using the inflatable hand to pour juice. Credit: MIT.

Users can form four main types of grasps: pinching two and three fingers together, making a balled-up fist, and cupping the palm. The prosthetic user can employ a combination of these four basic movements to perform various hand motions useful in day-to-day life. The grasping actions are aided by a tactile feedback system, which includes pressure sensors on each fingertip, so the user can gain a sense of the pressure they exert on an object and adjust accordingly.

This subject claims he could “feel” the cat as he petted it. Credit: MIT.

The movements themselves are controlled by muscle signals that are translated by computer algorithms into instructions that the prosthetic’s controller can understand.

The inflatable hand has only been trialed on two volunteers with upper-limb amputations so far. Each participant first underwent a brief 15-minute electromyography (EMG) training session, using sensors that record electrical signals from the residual limb. This way, when the user imagines clenching the hand into a fist, the prosthetic responds accordingly.

Despite the small sample of volunteers, the prosthetic performed wonderfully. The participants used the inflatable hand to write with a pen, turn pages of a book, eat foods like crackers and cake, and lift objects of various weights. When compared to commercially available bionic hands, the inflatable hand performed on par or better.

The researchers have filed for a patent of the design and hope to introduce the product to the market soon. There are over five million people across the world who have undergone an upper-limb amputation, and such a cheap but functional prosthetic could dramatically improve their quality of life.

In the meantime, Zhao and colleagues plan on tweaking and improving the design so it is fit for mass production. In time, this sort of remarkable technology could become the norm. For instance, philanthropist and entrepreneur Tej Kohli’s ‘Future Bionics’ program highlights just how assistive technology can substantially improve the quality of life for people living with disabilities.

“We now have four grasp types. There can be more,” Zhao says. “This design can be improved, with better decoding technology, higher-density myoelectric arrays, and a more compact pump that could be worn on the wrist. We also want to customize the design for mass production, so we can translate soft robotic technology to benefit society.”

The inflatable bionic hand was described in a recent study published in the journal Nature Biomedical Engineering.

Researchers fit Italian woman with futuristic, bionic hand

Almerina Mascarello lost her hand in a work accident — in July 1993, her hand was crushed by an industrial press. After almost 25 years, her luck completely changed.

An extraordinary fortunate event

 “I was flicking through a magazine on invalidity when I noticed a page asking people to undergo a test for a prosthesis. The Gemelli doctor phoned me a year later and asked me if I would like to be a guinea pig for a bionic hand“, she told ANSA.

“I said I would think about it and I said yes in May of last year. I went to Rome for the operation in June”Mascarello added.

Via Pixabay/Tumisu

The prosthetic — named LifeHand2 — was engineered by a team led by Silvestro Micera, from Scuola Superiore Sant’Anna in Pisa and the École polytechnique fédérale de Lausanne. Neurologist Paolo Maria Rossini’s team from Rome’s Policlinico Gemelli Hospital did the medical work.

How the hand works

The medical team inserted hair-thin electrodes into Almerina’s upper arm nerves. These electrodes conduct sensorial information from the hand to a computer in a backpack. The computer translates the gathered info into a language the brain can understand. Basically, the computer transmits to the upper arm nerves electrical signals, telling the brain the consistency and shape of the object.

bionic-hand

Almerina Mascarello opening a water bottle with the help of her new bionic hand. Credit: Youtube / Euronews.

A similar version of the bionic hand was priorly used by Danish patient Dennis Aabo Sorensen, who lost his hand in 2004 due to a firework explosion. His bionic hand was so sensitive that he was able to determine the consistency of different objects in 78 percent of cases. In 88 percent of cases, he could distinguish between a baseball, a glass, and a tangerine.

Credit: Youtube / Euronews.

The bionic hand is sophisticated enough to relay texture. Credit: Youtube / Euronews.

However, Mascarello’s implant and annexes were adjusted to fit into a backpack, unlike Sorensen’s. The bioengineering team’s goal is to create a hand prosthesis that has all the necessary components built in, miniaturizing the electronics as much as possible.

“We are going more and more in the direction of science fiction movies, like Luke Skywalker’s bionic hand in Star Wars – a fully controlled, fully natural, sensorized prosthesis, identical to the human hand.” lead researcher Micera told the BBC.

Sadly, Mascarello had to give up her prosthesis for further research. She felt like she was complete after 24 years, gathering joy from all the small things, like being able to tie her own shoes or dress alone. Unfortunately, only the research project is completed will she receive her own prosthetic hand.

“Now I’m eagerly awaiting them to call me and tell me it’s ready”, she stated.