Problem Statement: Individuals with paraplegia due to spinal cord injury (SCI) are unable to ambulate. Functional electrical stimulation (FES) of the lower extremities is one of the technologies with which ambulation can be partially restored. Current FES technology requires manual operation by the user, which is unintuitive, and monopolizes the upper extremities and interferes with their motor function. Brain-computer interface (BCI), on the other hand, is a technology that enables a direct cortical control of external devices, without generating any motor output. Research Plan: The main goal of this study is to integrate the technology of electro-encephalogram (EEG) based BCI with noninvasive FES of the lower extremities to restore intuitive, hands-free ambulation in individuals with complete paraplegia due to SCI. SCI subjects will be trained to utilize gait-related kinesthetic motor imagery (i.e. imagination of movement) to operate a BCI-controlled virtual reality gait simulator. The subjects will also be trained to ambulate with a commercial FES system. Subsequently, subjects' EEG data will be collected while they are engaged in ambulation with the FES system and the parameters critical for integration of BCI and FES systems will be determined. Finally, the two systems will be integrated, and the effectiveness of the integrated BCI-FES system will be tested in these subjects while they perform a goal-oriented ambulation task. Novelty: 1) The integration of an EEG-based BCI with limb prostheses has undergone limited research, and has not been achieved with lower extremity FES systems for walking. 2) The study requires a novel neurophysiological experimental paradigm, including novel signal processing and active-electrode recording methods, to enable acquisition of artifact-free, ambulatory EEG data. 3) These data will provide novel information about the neurophysiological processes underlying imagination and execution of ambulation in SCI. 4) A successfully integrated BCI-FES system will shift the focus of neuro-rehabilitation of this population from utilizing spared motor pathways to functional restoration. 5) This concept can be extended to future studies with much larger target domain, including subjects with stroke, multiple sclerosis, and incomplete SCI, as a novel tool to promote plasticity and neural repair and subsequent functional gains. Intellectual Merit: The proposed experimental, engineering and scientific techniques will provide a blueprint for future BCI-prosthesis integration studies. The proposed study will lead to the deployment and development of novel signal processing and control algorithms for BCI-prosthesis integration. Aside from BCI applications, the analysis of data collected in this study will delineate the general cortical areas involved in control of both executed and imagined gait, which will fundamentally advance our knowledge of cortical control of ambulation and the changes it undergoes due to SCI. The unique features of the integrated BCI-FES system and its long-term use will be instrumental to addressing scientific questions such as the emergence of the "BCI motor cortex," and may in the future facilitate development of novel treatments that utilize neural repair and plasticity, such as cellular therapies. Finally, the success of the proposed project may invigorate studies to refine FES technology and may inspire integration of BCIs with other forms of functional electrostimulation, such as spinal cord stimulation in rehabilitation of the target population. Broader Impacts: The proposed activities will enhance the education, scientific literacy, and lifelong learning in engineering and medical students. Specifically, elements of this study will be integrated into the teaching and mentoring curricula. Both undergraduate and graduate students will participate in the proposed research and educational plans and their findings will be broadly disseminated, including outreach to the disabled community. These activities will help develop students' leadership and interdisciplinary research skills. They will also broaden the participation of underrepresented groups in engineering and science. The investigators will promote college education and the pursuit of engineering/science careers in minority K-12 and community-college students by developing educational activities such as presentations, demonstrations and exhibits. Finally, the investigators will partake in the professional development of K-12 math and science teachers in high-need school districts in order to improve their retention rates and leadership skills.
