In that two-minute clip already more information in explanation than i've heard since this began in 2016. >> just to hear someone actually describe these unexplained health incidents, what transpired are somebody who never had these symptoms before, suddenly comes on, no advanced warning and no indication. i mean, concussion-like symptoms without a blow to the head. that's why they call it the immaculate concussion. it's hard to explain but you hear from somebody who is a physician himself, goes to investigating and gets that. >> do you get to the why? >> the prevailing theory as you probably ...