Symbiosis between humans and machines: evolution of prosthetics, from masking injuries to improving skills

Prosthetics were once simple body parts made of wood, plastic or metal alloys, mainly used to cover any deformities. Now, thanks to the efforts of countless scientists, they have become functional extensions of the human body.

For decades, prosthetic limbs were rigid devices that offered some degree of functionality but very limited control or adaptability. Users experienced limited control over movement. However, advances in robotics and bioengineering have led to modern prosthetics that go beyond covering deformities and help restore or even improve motor, sensory and neural abilities.

By integrating advanced sensors and artificial intelligence, these devices now mimic the natural movements of limbs, allowing users to control their medical prosthetics as if they were an extension of their own body. These prosthetics include sensors, motors and actuators, allowing for more complex and precise control.

A research team from the BioRobotics Institute, led by Prof. Christian Cipriani from the Sant’Anna School of Advanced Studies in Pisa, has developed the first-ever magnetically controlled prosthetic hand that allows users to use it as their own hand, with only their thoughts as part of the MYKI project.

This innovation allows an amputee to perform natural movements without having to rely on electrical connections and wires. Instead, the prosthesis uses myokinetic control. For this purpose, six magnets are implanted in six important places in the hand. When the test patient, 34-year-old Daniel, remembered to move his lost hand, the implanted magnets responded to the contractions, which in turn created signals that dictated the action to the robotic limb.

These advanced prosthetics not only give users a sense of control, but also provide sensory sensations that were previously impossible. One of those key technologies is MiniTouch, which can be integrated into various prostheses to provide the amputee with a feeling of warmth and coolness.

A research team from the same Sant’Anna School of Advanced Studies and the Swiss Federal Institute of Technology Lausanne developed this system that allows users to sense temperature, which has proven to be 100% accurate even when Fabrizio, a 57-year-old test patient, was blindfolded.

Bioelectronic interfaces have also led to a significant leap forward in modern medical prosthetics. This approach has allowed amputees to connect to their prosthesis on a deeper level through the person’s own nervous system. This type of interface essentially establishes bidirectional communication between the user’s peripheral nerves and their prosthesis, creating a human-machine symbiosis by enabling sensory feedback and natural proprioception.

While traditional prosthetics rely on sensors and mechanical controllers for every movement, this new interface, through a surgical process called the Agonist-Antagonist Myoneural Interface or AMI, reconnects the muscles in the remainder of the user’s limb and restores their proprioceptive feedback. This ability to sense limb position resulted in better obstacle navigation and walking speed in all seven patients who underwent the AMI procedure.

These AMI prosthetics provide seamless, lifelike movements, allowing users to naturally adjust their gait, navigate stairs and access a variety of terrains, with neural signals guiding each step. This small increase in neural feedback led to lifelike normal walking ability, which represented a substantial advance in the control and comfort of the prosthesis.

MIT’s biophysicist Hugh Herr and his team integrated the bionic leg with such a neural interface to give users a sense of self-esteem, providing both emotional and physical benefits. Patients with these neural interfaces that connect their bodies to machines have reported a 41% increase in walking speed and the ability to handle obstacles, stairs and inclines.

Non-invasive options are also improving. California-based Atom Limbs has developed an artificial intelligence and machine learning-powered bionic arm that provides human-like movements and haptic feedback. But unlike other prosthetics, which require surgery to interpret neuroelectric signals, this company promotes a non-invasive way to control the prosthetic limb using sports vests and straps wired with various sensors.

Armless since birth, Paul Carter, a reporter at the BBC, tested this new system and boasted of its ability to control virtual movements, creating the feeling that he was manipulating a missing limb; something he has never experienced before.

These types of groundbreaking leaps in prosthetic technology emerged from the advent of mind-controlled devices, which use brain-computer interface (BCI) technology to interpret neural signals directly from the user’s brain, allowing for a more intuitive, seamless control of artificial limbs becomes possible. Pioneers such as Elon Musk’s Neuralink and research teams from leading universities are pushing the boundaries of this innovation and increasing the responsiveness and adaptability of these prosthetics.

As advancements in prosthetic technology continue at an unprecedented pace, the line between humans and machines is becoming increasingly thin. What was once a simple tool for physical mobility is now a testament to human ingenuity, capable of restoring a deep sense of self to its users.

This symbiosis promises a future where the integration of humans and machines feels as natural as flesh and bones, bringing hope and empowerment to millions of people worldwide.