Neurotechnical Advancements bring promise to Amputees.

Neurotechnology advancements bring promise to amputees.Neurotechnology advancements bring promise to amputees. One reacher and his research team have made a breakthrough in below-knee prostheses. Imagine having a lower leg prosthesis that is so sensitive that when it is resting on a wall, you feel the pressure of the wall on your stump! Neurotechnical research is the integration of your existing neural system with your prostheses. The distinguished  2021 Science & PINS Prize for Neuromodulation has been awarded to Professor Stanisa Raspopovic, whose innovations in neurotechnology have led to a  new class of artificial legs that lead to an improved quality life for amputees and a way to end their phantom limb pain as well. Neurotechnology advancements bring promise to amputees.

Lower limbs left behind.

Neurotechnology advancements bring promise to amputees. Prosthesis research money is going to the development of fingers and hands. There is a higher priority in providing the use of a hand than in restoring the ability to walk. Prosthetic leg replacement has had no significant improvements since 1990. The technology is available. "I believe that the focus on upper limb amputation was because of the human fascination with the hand," says Raspopovic. The rise of peripheral arterial disease, such as diabetes, has seen the number of lower limb amputations far outstrip upper limbs. There are five hundred foot amputations every day in the United States alone. Yet the restoration of hands and fingers has a higher priority.

Intuitive Contact Brain to Prosthesis

There are more clinical options available for upper limb amputees. "You can do well with a static solution or with the complex use of the residual arm," says Raspopovic,” whereas individuals who have lost a leg need a mobile prosthesis to restore function.” Raspopovic is not impressed by all the eye-catching advances in robotics and mechanical design. Instead, he wants to improve the brain prostheses connection. "We tried to design a device that would enable intuitive contact with the residual nervous system," he says. "This is what patients want. They don't want a device that they have to struggle with. They want to use it intuitively." Raspopovic wants the prosthesis and the amputee to bond.

Neurotechnology advancements bring promise to amputees. The team first looks at intact limbs They carefully study the connections between the amputee’s brain and their peripheral nerves. The goal is to be able to map out exactly which nerves contributed to normal gait and movement. They then can develop an exact design with implanted electrodes to stimulate targeted areas of the nervous system. They created a sensory experience for prosthesis users that naturally mimics the feeling of an intact leg making it a seamless generic fit and nerve connection."We managed to create a language of stimulation that is appropriate to speak to the nervous system about the prosthesis. But, this research took a decade to become a reality," Raspopovic explains.

Raspopovic's leg recreates natural feelings of touch and pressure for the user. In addition, they created a connection so reliable that even when the amputee removed the prosthesis, they could tell if it is moved, or falls over. The sensors will connect with the stump even when taken off. This creates a bond between amputee and prosthesis that is almost organic. Many patients express it as if they have grown another leg.  Users' ability to navigate rugged terrain is also substantially improved. Major improvements in gait and stability have been reported. Fears of falling are greatly reduced as they can feel where they are stepping. They can feel movement in the ankle and shin as the ground becomes more uneven.

Reducing the risk of heart attack

The system had benefits beyond restoring movement. Amputees using traditional prostheses suffer from an increased risk of heart disease brought on by increased metabolic load when walking. "They suffer because their biomechanics are irregular," says Raspopovic. "You can see even when they are just climbing a staircase, they will be significantly more fatigued when compared to a non-amputee."  Psychological and cardiovascular stress is prevalent in lower limb amputees. Each of these factors may have systemic consequences on the arterial system and may contribute to the increased cardiovascular morbidity in traumatic amputees. By restoring the sensation of normal gait, users of Raspopovic's device were able to command more efficient movements and reduce their metabolic effort.

New Treatment for Phantom Pain

Amputees regularly suffer the intractable burden of phantom limb pain (PLP), where uncomfortable sensations emanate from a limb that is no longer there. Raspopovic's implanted electrode system could be set to a "neuro-pacemaker modality," where it released signals to the residual nerve that were able to reduce PLP. By focusing on stimulation that more naturally mimicked movements produced from an intact limb, Raspopovic's essay suggests that the system can remodel the peripheral and central nervous system to bring about a curative, rather than just painkilling effect on PLP. Many amputees who can't sleep because of phantom limb pain know what this research is saying and its consistency in other neurological treatments for intractable phantom pain.

Artificial Limb As Part of Their Bodies

But the most significant benefit of the system is not one that can be measured on a pain scale or in the number of steps walked. Instead, the improvement in how the patients saw the prosthesis as part of their bodies made the most significant difference. Despite typically being less than half the weight of a flesh and bone leg, traditional prostheses are often described as being uncomfortably heavy by users. In addition, increased cognitive load when using these older prostheses shows that the nervous system struggles to incorporate its new biomechanical component. In contrast, users reported improvements both to the "weight" of Raspopovic's limb and showed reduced cognitive load when using it.

Patient benefits

Neurotechnology advancements bring promise to amputees. The distinguished  2021 Science & PINS Prize for Neuromodulation was given to Raspopovic because of his essay describing his prototype showed so much success with major transtibial amputations and their complications. Raspopovic's essay discusses the societal benefits of a prosthetic system that could restore natural movement while reducing pain and cardiovascular burden. His greatest motivation is his designs' benefits to individual patients. A survey distributed to patients who had used his system showed amazing satisfaction. Once the amputees felt bonded to their prosthesis they write that it was like they grew a new leg. For example, in response to one question, "What would provide the biggest benefit?" one user said, "This prosthesis, ready."

Neurotechnology advancements bring promise to amputees. The system combines three functions—intuitive motor control, touch, and sensation. “We modified a prosthetic leg with this complex bionic system which enables wearers to move their prosthetic more intuitively,” said lead investigator Paul Marasco. By providing more realistic physical feedback and helping to alleviate phantom limb pain, Raspopovic's system led amputees to report a sense of "embodiment," or the feeling that a prosthetic is an extension of the wearer's body. Raspopovic wants to make the prostheses available to all who could benefit from it. "I like the part of the job where we are helping somebody. It's what is pushing us forward. I wouldn't do anything in life rather than this work," he concludes.

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