1. Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, Massachusetts, USA.
2. MassGeneral Hospital for Children Sports Concussion Program, Waltham, Massachusetts, USA.
3. Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, Massachusetts, USA.
4. Providence Veterans Administration Medical Center, Providence, Rhode Island, USA.
5. Department of Psychiatry and Human Behavior, Alpert Medical School of Brown University, Providence, Rhode Island, USA.
6. Spaulding Research Institute, Charlestown, Massachusetts, USA.