A concussion (orig. Latin: concutere, "to shake violently”) is a clinical diagnosis of a biomechanically-induced alteration in brain function. This impairment is usually reversible and often affects memory, orientation, and attention. It may or may not cause a loss of consciousness and does not show evidence of brain damage on computed tomography (CT) or
magnetic resonance imaging (MRI) scans. (1,2) The internationally accepted consensus definition of concussion incorporates several criteria. (3)
1. Concussion may be caused by a direct blow to the head, face, neck, or elsewhere on the body with an “impulsive” force transmitted to the head.
2. Concussion typically results in the rapid onset of short-lived impairment of neurologic function that resolves spontaneously. However, in some cases, symptoms and signs may evolve over a number of minutes to hours.
3. Concussion may result in neuro-pathological changes, but the acute clinical symptoms largely reflect a functional disturbance rather than a structural injury, and as such, no abnormality is seen on standard structural neuroimaging studies.
4. Concussion results in a graded set of clinical symptoms that may or may not involve loss of consciousness. Resolution of the clinical and cognitive symptoms typically follows a sequential course. However, it is important to note that in some cases symptoms may be prolonged