We don’t know why a second concussion is a greater risk or may have more dangerous consequences than a first concussion. But we think it may have something to do with the young-adult brain. They syndrome called Second Impact Syndrome only occurs in young adults before the age of 24. It may have to do with this sort of immaturity of their brain and handling brain swelling and handling the electrolyte changes that occur after a brain injury, but we’re not certain. But certainly, sometimes a second concussion, especially in a young adult can be catastrophic.