The “Ember Arm” is here - researchers from the Medical School and the Faculty of Engineering and Information Technology of Pécs are developing a teachable artificial limb

9 June 2020

Researchers of the University of Pécs Medical School are working on a “self-learning” artificial limb controlled by artificial intelligence at the University of Pécs 3D Center. The upper limb prosthesis, developed jointly with Corvus-Med Kft., which provides professional support, acquires the wearer's frequent movements and gestures through an integrated learning system and hopefully it will reach those most in need through social security (TB) ​​support in the future. We have looked at the already working prototype.

 

Written by Miklós Stemler

 

Grabbing a ball, opening a bottle, putting on a sock - those who lose their forearms because of an accident, illness, or birth defect have to cope with such tasks, which are unconscious and routine tasks for the most of us. All this affects more than 500,000 people worldwide and this number is growing rapidly since a significant part of the causes of amputation are the result of diseases (infections, malignant tumours and vasoconstriction) that are increasingly affecting aging societies in addition to accidents.

From wooden hands to limbs controlled by artificial intelligence

While the rapidly developing limb prostheses are a great help in replacing missing body parts, even the most advanced models have plenty of limitations: their use is difficult to master, they may not be able to perform really delicate hand movements, and wearing them for a long time is particularly tiring.

Limb prosthesis developments have been going on in the University of Pécs 3D Center for years, and the cooperation of the Center with Corvus-Med Kft., which is an important market participant in the production of medical aids, has given a great boost to these. Through several years of cooperation, formalized in 2019, the theoretical knowledge of the Medical Group of the researchers of the University of Pécs has been enriched with the practical experience of the company, which is on the market for more than a decade, and one of the first results of this is the “Ember Arm”.

Artificial limbs have undergone a huge transformation in recent decades and in addition to the increasingly sophisticated cosmetic prostheses, functional prostheses have also emerged for some time now, capable of replacing the functionality of the lost limbs at various levels and in different ways. In addition to simple mechanical solutions that can only open and close the hand, so-called myoelectric prostheses are already in use as well, which work through electrical signals generated by human muscles.

As Csaba Csóka, executive director of the Corvus-Med Kft. and coordinator of the development explains, it is possible in a way that muscle groups remain after the amputation and in the case of developmental disorders and if the electrodes needed for the prosthesis are put in the right place, the electrical signal generated by the muscle contraction is transmitted to the prosthesis. Such a so-called bionic prosthesis is capable even of finer movements but it still has serious limitations: it takes a long time to learn and is difficult to fine-tune. “Most currently available limb prostheses come with a pre-determined package: they can perform, say, 30 common types of movements and their range cannot be extended,” says dr. Luca Tóth, medical consultant of the project. The Pécs team, on the other hand, has a different perspective.

“While normally the user has to master how the prosthesis works, we changed this process and said what would happen if the prosthesis learned the user’s movements, constantly adapting if necessary” - says dr. Ádám Schiffer, associate professor at the University of Pécs Faculty of Engineering and Information Technology and coordinator of the prosthesis software development. An artificial intelligence, i.e. a learning system is responsible for this, which constantly monitors the activity of the user's muscles. Although you might even think of supercomputers when you hear the phrase artificial intelligence, the Rapsberry Pi, which costs a few tens of thousands HUF also has the computing capacity needed for the task and such a minicomputer will be installed in the device as well, adds Dhakshinamurthy Devaraj, leader of the prototype development.

With the help of virtual reality for a really useful artificial limb

The customizable prosthesis can be controlled and fine-tuned with a mobile application and a screen placed on it and its use can be practiced with the help of virtual reality, even with the help of various games. All this can be especially helpful for children who have an already high rate of “prosthesis abandonment” of 35 percent according to a survey, i.e. those who find their artificial limb so uncomfortable, cumbersome and useless that they give up using it.

This is also true for a quarter of adult users and according to the project’s medical consultant, dr. Luca Tóth these proportions may be even worse in reality, simply because the vast majority of users are dissatisfied with the knowledge of their prosthesis and find its regular use exhausting and tiring. Therefore, it is important that the prosthesis developed in Pécs is lighter than most models on the market despite the built-in minicomputer and although this advantage is only 10-20 decagrams, it is of great importance for long, all-day use. Moreover, due to the 3D printing manufacturing technology, the individual pieces can be completely customized, which can be especially important for children who are reluctant to use prostheses.

The prosthesis also has “tactile feedback”, meaning there are sensors at the end of each finger that provide feedback in proportion to the strength of the grip, simulating touch. All this can be especially important in mastering and maintaining delicate hand movements because the brain is able to adapt to these based on continuous feedback. 

The price of equipment similar to the one being developed in Pécs, capable of moving each finger separately is around 13-15 million HUF. They are trying to determine the price of the model developed here significantly cheaper, around 8 million HUF, which, of course, is affordable for only a relatively few people. TB support could be at least partially a solution, it can be obtained through individual licensing for bionic prostheses according to the current procedure - the team is currently working on the “Ember Arm” to be put on the list of supported devices.

In addition to the final prosthesis, the developers in Pécs are also working on a so-called learning module, with the help of which rehabilitation can begin as soon as possible after the loss of a limb. With a much simpler model than the final version, the use of the prosthesis can be easily mastered, while a virtual reality system and playful teaching make it easier for children to get used to it.

“Ember Arm” currently has a working, user-tested prototype. In the next months, the fine-tuning of the model will take place and in six months, the version to be produced may be ready. However, once the technical work is completed, the team will not reach the goal yet because this will be followed by the search for investors and the conduct of broader clinical trials. Dr. Péter Maróti, the professional manager of the UP 3D Center estimates that it will take about a year for the “Ember Arm” to reach the ones in need.

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