About the Authors

Martin D. Hoffman

martin.hoffman@va.gov

Affiliation Department of Physical Medicine & Rehabilitation, Department of Veterans Affairs, Northern California Health Care System, and University of California Davis Medical Center, Sacramento, California, United States of America

Eswar Krishnan

Affiliation Department of Medicine, Stanford University School of Medicine, Palo Alto, California, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: MDH EK. Performed the experiments: MDH EK. Analyzed the data: MDH. Contributed reagents/materials/analysis tools: MDH EK. Wrote the paper: MDH EK.