KIRKWOOD, Ill. -- Every two hours, the memory of one Illinois teen resets. When she wakes up every morning, Riley Horner believes it's June 11 - the day she received a traumatic head injury."I have a calendar on my door. I look and it's September and I'm like, 'Woah'," Riley told local television station WQAD June 11 was the day Riley was accidentally kicked in the head by a student crowd surfing during a dance. But after dozens of seizures and countless hospital visits, her symptoms are still a medical mystery.Riley's first doctor dismissed it as a concussion and simply sent her home on crutches."They tell us there's nothing medically wrong," Sarah, her mother, told WQAD. "They can't see anything. You can't see a concussion though on an MRI or a CT scan. There's no brain bleed, there's no tumor."Even the simpler things in life are wiped out of Riley's memory. Riley carries every notebook, textbook and pencil with her throughout the day because she can't even remember where her locker is.In order to keep up with school, Riley needs to leave herself detailed notes, take photos of them on her phone, and set an alarm for every two hours so she can brush up on what she has forgotten."My brother passed away last week and she probably has no idea. We tell her every day but she has no idea about it," Sarah said."I know it's hard for them as much as it's hard for me. And people just don't understand. It's like a movie," Riley said. "I will have no recollection of [this interview] come suppertime."