What is a concussion?

When the head is hit or suddenly jerked, the brain can move inside the skull, stretching nerve cells and disrupting brain chemistry. Symptoms include headache, dizziness, confusion, nausea, sensitivity to light and memory problems, and loss of consciousness happens in only a minority of cases. Most people recover within a few weeks with rest followed by gradual return to activity. Repeated head injuries are linked to chronic traumatic encephalopathy (CTE), a degenerative brain disease found in some former athletes. Many sports now use head injury assessments and “if in doubt, sit them out” rules.