Firstly, a concussion is the mildest form of brain injury, mainly characterized by transient consciousness disturbances, generally not lasting more than half an hour. The second characteristic is recent memory loss, with an inability to recall the circumstances of the injury. At the time of the injury, one may also experience pale complexion, blood pressure drop, and pupil constriction. After the injury, some patients may suffer from dizziness, headache, nausea, loss of appetite, tinnitus, lack of concentration, and memory decline, among other clinical symptoms. Patients with a concussion generally recover after 1-2 weeks of systematic treatment, and the majority of concussions are recoverable, so they are not as fearsome as believed.