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Brain-machine interfaces (BMIs) offer the promise of restoring communication, enabling control of assistive devices, and volitional control of extremities in paralyzed individuals. Working in multidisciplinary teams, neurosurgeons can play an invaluable role in design, development, and demonstration of novel BMI technology. At the NIH, the National Institute of Neurological Disorders and Stroke has a long history in supporting neural engineering and prosthetics efforts including BMI and these research opportunities continue today. The purpose of this editorial is to provide a brief overview of the opportunities and programs available currently available to support BMI projects.
Brain-machine interfaces (BMIs) provide a pathway for communication between the brain and devices that are either external or internal to the patient. By bypassing damaged regions of the nervous system resulting from trauma or disease, BMI has significant implications for restoration of: communication for locked-in patients, volitional control of paralyzed limbs through activation of implanted neuromuscular stimulation systems, and possibly sensorimotor function in prosthetic limbs4. BMIs are being realized through cooperative, multidisciplinary efforts from basic neuroscientists, biomedical engineers, and neurosurgeons. The foundation of BMI is firmly embedded in basic neuroscience which aims to elucidate how the brain controls movement and the capacity of brain circuitry to undergo adaptation. By leveraging advances in the microelectronics industry and computer engineering, the BMI field has capitalized on precisely microfabricated neural interfaces8 and, more importantly, high-speed data acquisition and processing to enable real-time use. In general, there are three classes of BMIs that vary with respect to invasiveness and are widely viewed to differ with respect to data rates. The least invasive approach, electroencephalography (EEG), is widely used in clinical neurology for diagnostic applications and is based on decoding scalp-derived potentials and rhythms1. While EEG potentials consist of the cumulative spike activity of many localized and similarly oriented neurons, invasive BMIs consisting of microelectrode arrays simultaneously monitor spike activity from populations of distinguished units, each representing putative individual neurons6.Electrocorticography, which relies on subdural recording grids to record field potentials, has emerged as an intermediate approach that may offer a compromise with respect to invasiveness but with high performance7. While these devices hold significant promise for relieving the burden of neurological disease and injury, the field is currently at a nascent stage requiring cultivation through federal support. The purpose of this brief editorial is to provide an overview of how the National Institute of Neurological Disorders and Stroke (NINDS) has supported BMI research in the past and to describe opportunities and programs available currently available to support BMI projects.
The initial scientific driving force for developing devices that interface with the nervous system emerged in the late 1950s when the first detailed description emerged of the effects of direct electrical stimulation of the auditory nerve in deafness resulting in perception3. In 1968, Brindley and Lewin described the visual percepts of a blind individual who had undergone implantation of an array of electrodes on the surface of occipital cortex2.This work and other related efforts spawned a series of questions concerning electrode robustness and stability, tissue/device compatibility, fundamental mechanisms of neural excitation by electrical stimulation, and principles of information encoding and transfer with the nervous system. Given the targeted and interdisciplinary nature of these initial questions, the NIH Neural Prosthesis Program5 was launched in 1970 and achieved a number of accomplishments under the leadership of Drs. K. Frank, T. Hambrecht, and W. Heetderks. Among the most significant achievements of the program has been the cochlear implant, a neural interface that provides a sense of sound to individuals who are profoundly deaf or severely hard-of-hearing by processing sounds from the environment and directly stimulating the auditory nerve.
More recently, projects within the Neural Prosthesis Program have been able to utilize grant programs to support BMI research and development. In 1997, the NIH recognized the potential contributions of bioengineering to the mission of relieving the burden of disease and implemented a set of related funding opportunities. A key feature of these programs is that each allows the pursuit of milestone-oriented, rather than hypothesis-driven aims, consistent with engineering design and development activities. Current bioengineering program announcements support neural engineering activities including BMI research:
Proof-of-concept demonstration of neurotechnology presents opportunities in the private sector. NINDS supports small business activities in neurotechnology through the parent small business innovation research (SBIR) and small business technology transfer (STTR) programs listed in the NIH Omnibus1. In addition, NINDS calls for SBIR and STTR research pertaining to BMI through the Neurotechnology Research, Development, and Enhancement program (SBIR phase I and II: PA-07-389; STTR phase I and II: PA-07-390). To bridge the gap between the bench and the clinic, NINDS is offering new program announcements for cooperative agreement-based grants encouraging translational and pilot clinical studies for neural prosthetics:
These programs provide funding for milestone-driven projects for the design, development, and demonstration of clinically-useful neural prosthetic devices including BMI. Activities to be supported in this program include implementation of clinical prototype devices, preclinical safety and efficacy testing, design verification and validation activities, pursuit of regulatory approval for clinical study, and proof-of-concept or pilot clinical studies. With these cooperative agreement mechanisms, there is significant participation of NIH staff in the evaluation of milestones and coordination with other neural engineering activities supported by the NIH or by other federal agencies.
The commitment of the NIH to fostering neurotechnology-related research extends beyond the development of programs. In 2007, the NIH Center of Scientific Review established a new Integrated Review Group in 2007 entitled Emerging Technologies and Training in Neurosciences (ETTN). Within ETTN, The Neurotechnology (NT) standing study section considers applications seeking to develop and utilize computational, informatic, imaging, biophysical, and bioengineering approaches for neuroscience. NT provides a review forum for consistent and expert review of proposals for BMI and neuroprosthetic devices.
In the BMI field, research teams that engage neurosurgeons as full partners in the endeavor are poised to have significant impact. Obviously, neurosurgeons have a critical role in realizing clinical demonstrations of this nascent technology. But, their contributions can also be made earlier in the project through the Design Control process (design reviews, design verification, and design validation), a key activity for regulatory approval.
The views expressed here are those of the authors and do not represent those of the National Institutes of Health or the US Government. No official support or endorsement by the National Institutes of Health is intended or should be inferred.