Bionics and Neuroprosthetics: The Future of Functionality with Biomedical Engineering

By Deliana InfanteReviewed by Danielle Ellis, B.Sc.

The intersection of biology and technology
The science of bionics and neuroprosthetics
Achievements and milestones
Challenges and ethical considerations
Companies paving the way 
References 
Further reading

Bionics and neuroprosthetics are two fields of biomedical engineering that aim to restore or enhance lost functions in people with sensory, motor, or cognitive impairments by designing artificial devices that mimic natural biological systems.

The intersection of biology and technology

Biomedical engineering, the convergence of medicine, biology, and engineering, has evolved over the years in response to advances in science and technology. From the creation of the first kidney dialysis machine to the development of artificial limbs, biomedical engineering has made significant strides in improving the quality of life for many people.

Bionics and neuroprosthetics are key to these advances. These disciplines are closely linked to the development of microsystems technology, nanotechnology, information technology, biotechnology, and the application of new materials. These devices use electrical stimuli to stimulate neural structures to support, augment, or partially restore the impaired or lost function.

The science of bionics and neuroprosthetics

The foundation of bionics and neuroprosthetics is the seamless integration of biological systems with artificial mechanisms. By exploiting principles such as biocompatibility and neuroplasticity, researchers have successfully developed biomedical products that mimic natural body functions. Notable examples include Cochlear implants, retinal implants, and prosthetic limbs.

Cochlear implants work by converting sound into electrical signals that stimulate the auditory nerve directly, bypassing damaged ciliated cells, and retinal implants convert light into electrical signals that travel through the optic nerve.

Advanced prosthetic limbs have also made significant advances in mimicking natural movement. They use sensors, microprocessors, and myoelectric technology that the user's own neural signals can control.

One example is the e-OPRA implant system developed by Integrum AB. It attaches the prosthetic arm to the bone in the amputated stump, and electrodes implanted in the muscles and nerves of the amputated arm, along with an embedded connector, create an electrical interface. These electrodes connect to sensors in the body through the Integrum control system in the prosthesis. By transmitting sensory input from the prosthesis back to the user, they can control its movement.

All of these prostheses and devices operate through neural interfaces, which are the fundamental link between the biological system and the machine. Several types of neural interfaces are currently in use. Brain-computer interfaces (BCIs) are one of them.

BCIs provide a direct link between the brain and an external device, allowing individuals to control devices using their neural signals. BCIs can use invasive or non-invasive techniques such as electrocorticography (ECoG) or electroencephalography (EEG). They have shown promise in assisting people with amyotrophic lateral sclerosis, cerebral palsy, stroke, or spinal cord injury.

Other approaches include peripheral nerve interfaces, which connect peripheral nerves to the prosthetic limb to allow bidirectional communication. Techniques such as targeted muscle reinnervation (TMR) reroute nerves to activate specific muscles, allowing users to control the prosthesis more intuitively.

Finally, optogenetics-based interfaces are another promising neural interface. Optogenetics combines genetic engineering and light-sensitive proteins to control neural activity using light. This technique has shown potential for modulating neural circuits and restoring function in animal models, but its clinical application is still in the early stages of research.

Achievements and milestones

There are several successful case studies of patients benefiting from bionics and neuroprosthetics. One of the most recent examples is the case of a 27-year-old patient with unilateral obstetric brachial plexus injury (OBPI). People with severe OBPI typically face significant limitations in their daily lives due to limited hand-arm function, and traditional reconstructive methods often fail to restore their use.

This patient underwent bionic reconstruction, including elective amputation, humeral de-rotation osteotomy, and myoelectric prosthetic fitting. Functional assessments and self-reported questionnaires showed significant improvement in hand function and independence in daily activities.

Another example is the research conducted by the Cleveland Clinic in 2021, where researchers developed a groundbreaking neurorobotic prosthetic arm for upper extremity amputees. This bionic system enhanced the wearer's ability to think, behave, and function much like a person without an amputation. Combining intuitive motor control, touch, and grasp kinesthesia, the prosthetic arm provided bidirectional feedback and control.

Two participants with upper limb amputations who had undergone targeted sensory and motor reinnervation successfully tested the bionic limb, achieving a level of accuracy comparable to non-disabled individuals. These studies demonstrate the significant impact that advances in these areas can have on improving patients' quality of life.

Challenges and ethical considerations

Despite their significant advances, these fields still face several challenges and limitations. One of the main challenges is the specificity of the feedback provided by these devices. Patients often experience irritation or shock-like sensations, which can be a barrier to the successful implementation of these technologies.

In addition, there are health risks associated with implanting any device in the body, as these devices affect the neural wiring of the individual.

In addition, the long-term viability and biocompatibility of stimulation electrodes, the selection of appropriate strategies for each patient, and a better understanding of brain plasticity are some of the technical and biological challenges that remain to be overcome.

The rapid advances in bionics and neuroprosthetics also raise several ethical concerns. For example, there are issues related to informed consent, especially for patients with locked-in syndrome.

Privacy and security issues are other areas of concern. Therefore, it's important to balance the potential benefits of these technologies with their ethical implications.

Companies paving the way

Several companies are contributing to the advancement of bionics and neuroprosthetics. Some of them are Medtronic PLC, Edward Lifesciences Corporation, Ekso Bionics and Ossur (Touch Bionics), LivaNova PLC, Demant A/S, Cochlear, and NeuroPace Inc.

Today, Medtronic is the global leader in this industry due to its extensive global presence, innovative solutions, and significant investment in research and development. The company operates in 160 countries, providing treatments for more than 70 medical conditions.

Medtronic has developed a broad range of products, including deep brain, spinal cord, and peripheral nerve stimulation systems. In terms of future developments, Medtronic has shown its desire to create new solutions to treat a wider range of health conditions.

This briefly shows the great impact and presence these companies have in the healthcare industry and how they continue to innovate with ongoing research and development efforts to create better solutions for patients with disabilities.

References

• Boesendorfer A, et al. (2022). Case report: Bionic reconstruction in an adult with obstetric brachial plexus injury. Frontiers in Rehabilitation Sciences, 2. https://doi.org/10.3389/fresc.2021.804376
• Cheesborough J, et al. (2015). Targeted muscle reinnervation and Advanced Prosthetic Arms. Seminars in Plastic Surgery, 29(01), 062–072. https://doi.org/10.1055/s-0035-1544166
• Clausen J, et al. (2015). Ethical Implications of Sensory Prostheses. In Handbook of neuroethics. essay, Springer Netherlands.
• Kansaku K. (2021). Neuroprosthetics in Systems Neuroscience and medicine. Scientific Reports, 11(1). https://doi.org/10.1038/s41598-021-85134-4
• Marasco P. D , et al. (2021). Neurorobotic fusion of prosthetic touch, kinesthesia, and movement in bionic upper limbs promotes intrinsic brain behaviors. Science Robotics, 6(58). https://doi.org/10.1126/scirobotics.abf3368
• Miller K. J, et al. (2020). The current state of electrocorticography-based brain–computer interfaces. Neurosurgical Focus, 49(1). https://doi.org/10.3171/2020.4.focus20185
• More amputees can better control prosthetics with controls that capture and interpret brain signals. ASME. (n.d.) [online] https://www.asme.org/topics-resources/content/three-advances-in-prosthetics
• Bionics market size & share analysis - industry research report - growth trends. Bionics Market Size & Share Analysis - Industry Research Report - Growth Trends. (n.d.) [online] https://www.mordorintelligence.com/industry-reports/bionics-market
• Medtronic. (n.d.). Key facts about Medtronic. Healthcare technology for the digital age. [online] https://www.medtronic.com/us-en/our-company/key-facts.html

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