The only time I ever saw Mohammed Ali in person was the night he shook and trembled, but still lit the Olympic Torch in Atlanta during the 1996 opening ceremonies. There's debate about whether his boxing career with its head trauma or pesticide exposure or other factors caused his Parkinson's Disease. No matter what the cause he received medical attention regarding his having the neurologic complications of his Parkinson’s Disease and his likely having experienced traumatic brain injury during his boxing career. Not all children who suffer traumatic brain injury, especially young athletes get such attention or are monitored for complications of possible head injury by their health care clinicians.
New work published in Pediatrics from Bryan et al. (10.1542/peds.2015-4635) estimates 1.1 to 1.9 million children and adolescents experience traumatic brain injury each year while playing sports or during recreational activities. An estimated 44 million children participate in sports annually. (1) The University of Washington researchers also estimated that most children with such injuries -- between 511,590 and 1,240,972 -- didn't get any medical attention.
The researchers used three national databases to provide what is considered the most accurate and precise estimate of such injuries. The data sources were MarketScan, National Electronic Injury Surveillance System and the online reporting system of the National High School Sports Related Injury Surveillance System. Until this estimate was developed, the most cited estimate was 1.6 million to 3.8 million that was developed using data from the Injury Supplement of the 1991 Health Interview Survey. (2)
The estimate of the incidence and the number of children who don't get care after a head injury are important in defining the magnitude of a problem. The Institute of Medicine (I think they now call it the National Academy of Medicine) has recommended the establishment of a routine surveillance system for such injuries and the Centers for Disease Control is establishing such a system. (3) Much attention has been paid to the outcomes of professional football players in the National Football League who suffer head trauma during play, but the problems starts at a younger age. Being able to accurate count such head injuries will provide needed data for the pediatricians who take care of children who plays sports.
