Advancing technology for military uniforms, body armor and equipment have saved countless lives of our servicemembers injured on the battlefield. Unfortunately, many of those survivors are seriously and permanently wounded, with unprecedented rates of limb loss and traumatic brain injury among our returning soldiers. This crisis has motivated great interest in the science of and technology for restoring sensorimotor functions lost to amputation and injury of the central nervous system. For a decade now, DARPA has been leading efforts aimed at ‘revolutionizing’ the state-of-the-art in prosthetic limbs, recently debuting 2 advanced mechatronic limbs for the upper extremity. These new devices are truly anthropomorphic and capable of performing dexterous manipulation functions that finally begin to approach the capabilities of natural limbs. However, in the absence of a high bandwidth, intuitive interface for the user, these limbs will never achieve their full potential in improving the quality of life for the wounded soldiers that could benefit from this advanced technology.
DARPA created the Reliable Neural-Interface Technology (RE-NET) program in 2010 to directly address the need for high performance neural interfaces to control dexterous functions made possible with advanced prosthetic limbs. Specifically, RE-NET seeks to develop the technologies needed to reliably extract information from the nervous system, and to do so at a scale and rate necessary to control many degree-of-freedom (DOF) machines, such as high-performance prosthetic limbs. Prior to the DARPA RE-NET program, all existing methods to extract neural control signals were inadequate for amputees to control high-performance prostheses, either because the level of extracted information was too low or the functional lifetime was too short. However, recent technological advances create new opportunities to solve both of these neural-interface problems. For example, it is now feasible to develop high-resolution peripheral neuromuscular interfaces that increase the amount of information obtained from the peripheral nervous system. Furthermore, advances in cortical microelectrode technologies are extending the durability of neural signals obtained from the brain, making it possible to create brain-controlled prosthetics that remain useful over the full lifetime of the patient.
The RE-NET program has released a total of three Broad Agency Announcements (BAA) for understanding why the performance of neural interface cannot be maintained for several years and to develop new high-performance neural interfaces that last for the life of the patient. The first focused effort within the RE-NET program, Histology for Interface Stability over-time (HIST, BAA 10-32), seeks to determine the dominant mechanisms leading to failure of neural interfaces. This effort has not only identified critical biotic failure mechanisms, but also numerous abiotic failure mechanisms that were unforeseen and/or underappreciated by the brain-machine-interface community. A second focused effort in the RE-NET program, Reliable Central-Nervous-System Interfaces (RCI, BAA 11-37), works to build new interface devices for the brain and spinal cord that are designed to overcome or prevent the failure modes identified in the HIST effort. A third focused effort, Reliable Peripheral Interfaces (RPI, BAA 11-08), works to develop reliable high-performance in-vivo peripheral motor-signal recording and sensory-signal stimulating interfaces. The RPI effort involves the use of novel approaches, designs, fabrication processes, testing methods and analysis techniques to demonstrate substantial improvements in the quantity of peripheral motor-signal information while maintaining long-term reliability.
Ultimately, DARPA seeks clinically viable technologies, enabling wounded servicemembers with amputations to neurally control state-of-the-art prosthetic limbs. The goal is to assist them in returning to active duty and to improve their quality of life. Program developments may impact the broad community of patients with medical amputations, spinal cord injuries and neurological diseases.
The intent by DARPA to support the development of advanced technologies to address the needs of the DoD amputee population and have resulted in many direct and tangible accomplishments.. RE-NET neural-interface systems are being improved and human amputees are already experiencing the benefits of improved limb control. It is expected that additional RE-NET research outcomes will improve the capacity of peripheral interfaces to extract even more limb-control information, thereby providing even more functional benefit to amputees.
Dr. Douglas Weberdouglas.email@example.com