Brain function disrupted. A concussion may result in neuropathological changes but the acute clinical symptoms largely reflect a functional disturbance in the brain rather than structural injury.
Loss of consciousness not required. Concussions result in a graded set of clinical symptoms that may or may not involved loss of consciousness (LOC). Resolution of clinical and cognitive symptoms typically follow a sequential course, but in a small percentage of cases, post-concussive symptoms may be prolonged.