Defining concussion: Current concepts and diagnostic criteria.

Concussions are some of the most common neurological diagnoses in the world, affecting millions of people every year. There have been attempts over the years to define concussion as part of the spectrum of traumatic brain injury (TBI). Symptoms of a concussion can be varied, and the duration of symptoms can differ based on pre-morbid conditions. While concussions are diagnosed clinically, there is a role for standardized tools in aiding this diagnosis. There may also be a clinical role for various forms of neuroimaging, biomarkers, and other diagnostic measures in the future.