1. Department of Biomedical Engineering, University of California at Irvine, Irvine, CA, USA
2. Department of Biomedical Engineering and the Department of Electrical Engineering and Computer Science, University of California at Irvine, Irvine, CA, USA
3. Rancho Los Amigos National Rehabilitation Center, Downey, CA, USA
4. Department of Neurology, University of California at Irvine, Irvine, CA, USA