1. VA Portland Health Care System, Portland, OR
2. Department of Neurology, Oregon Health and Science University, Portland, OR
3. School of Nursing, Oregon Health and Science University, Portland, OR
4. Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR
5. Department of Medicine, Division of Pulmonary and Critical Care Medicine; Oregon Health & Science University, Portland, OR
6. Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland, OR