how long it takes before concussion symptoms
Concussion (mild traumatic brain injury) Overview. A concussion is a mild traumatic brain injury caused by a blow or ding to the head. Common in falls, sports, and car crashes, concussions can temporarily affect the brain, causing confusion and problems with memory, speech, vision, or balance. The person may appear fine at first but may show symptoms hours or days later. If left undiagnosed, a concussion may place a person at risk of developing second-impact syndrome, a potentially fatal injury that occurs when an athlete sustains a second head injury before a previous head injury has healed.