Published online by Cambridge University Press: 01 January 2021
Concussion is a form of mild traumatic brain injury (mTBI) that can occur as a result of contact to the head or other parts of the body that causes a rapid acceleration-deceleration force to the brain that may cause a functional disturbance in an individual’s ability to concentrate or learn new information. Contrary to popular belief, it is not a bruise to the brain, and there is usually nothing detectable on standard imaging such as a computed tomography or magnetic resonance imaging. Symptoms and signs are therefore important to detect and include decreased levels of consciousness, headache, nausea, difficulty concentrating, memory loss, and poor coordination. These signs and symptoms usually occur within minutes after the injury but may also appear several hours or even days later.