Firstly, a concussion is a relatively mild condition where the brain sustains damage, usually accompanied by disturbances in consciousness, which are temporary, such as unconsciousness lasting no longer than half an hour. The second symptom is akin to amnesia, where the injured person is unable to recall the circumstances of the injury. At the time of the injury, symptoms such as a drop in blood pressure and pale complexion can occur; some patients may also experience dizziness, headache, nausea, loss of appetite, poor sleep, as well as a range of clinical manifestations including lack of concentration and memory decline.