1. Department of Physical Medicine and Rehabilitation, Mayo Clinic College of Medicine, Rochester, Minnesota.
2. Department of Psychiatry and Psychology, Mayo Clinic College of Medicine, Rochester, Minnesota.
3. Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
4. Department of Physical Medicine and Rehabilitation, Santa Clara Valley Medical Center, and Department of Functional Restoration, Stanford University School of Medicine, San Jose, California.
5. Department of Physical Medicine and Rehabilitation, Virginia Commonwealth University, Medical College of Virginia, Richmond, Virginia.