A concussion is a type of mild traumatic brain injury (TBI) that occurs when a sudden impact or jolt to the head causes the brain to move rapidly within the skull. While the injury itself is often not visible on imaging tests, concussions can lead to a range of physical, cognitive, and emotional symptoms. These may include headaches, dizziness, nausea, fatigue, sensitivity to light or noise, difficulty concentrating, and memory problems. Most people recover from a concussion with proper rest and care, but for some, symptoms can persist for weeks or even months, a condition known as post-concussion syndrome (PCS).