A Concussion is a mental change that happens at the time of trauma, or begins just a few minutes later. If there’s complete loss of consciousness, it refers to the time after the person comes to. If the change persists 30 minutes, it gets classified as mild Traumatic Brain Injury (TBI). Exact definitions get created to try and determine future effects and prognosis. Concussion is due to disruption of nerves in the brain, which usually come back to normal.
Symptoms include amnesia for the event; if more severe, there’s amnesia going further back in recent time, and for new events occurring after, like if a person keeps asking a question that’s already been answered. A common test is seeing if they can recall three common words at 5 minutes. Other symptoms may include dizziness, poor coordination, slow or slurred speech, a blank stare, trouble concentrating or delayed responses, and acting excessively emotional.
Various levels of sports have various tools and requirements to assess whether athletes can return to play. You can google recommendations from the American Academy of Neurology, since they may change regularly (like all medical recommendations), or the “SCAT5”. But always remember that on the field, when somebody has head trauma, the most dangerous and often overlooked possibility is a broken neck (see Head Trauma).
Most persons with concussions do not require X-rays, CT Scans or MRIs (called “imaging”). These only show major brain or skull damage, not the most common disruption of nerve circuits which can cause significant disability. I’ve seen patients distressed because they’re experiencing symptoms, and get told “the CT was normal,” or “it didn’t show anything.” There are criteria for who needs imaging; you can google “Canadian CT head rule (CCHR),” “New Orleans criteria (NOC),” “National Emergency X-Radiography Utilization Study II (NEXUS II),” or recommendations of the American College of Emergency Physicians.
Post-Concussive Syndrome refers to a variety of symptoms lasting at least 3 months after head trauma, or other events like whiplash which may shake the brain. They include various types of headache, dizziness, memory problems, sleep difficulty, and general trouble concentrating or thinking. It’s a difficult topic to define, because its manifestations are so varied, and may be complicated by health issues a person had before the injury. It has also been recognized, for virtually any type of injury, that pending lawsuits or disability applications get in the way of recovery (it doesn’t make sense to our subconscious minds for us to feel better while still trying to sue).
Neurological and psychological testing doesn’t seem to help much. Treatment, both medication and psychological, is by trial and error, although one recommendation that has been debunked is “mental rest.” People should return to their normal activities to the extent they feel comfortable.