What do we know about head trauma in high school and college football?.
Mild Traumatic Brain Injury ( mTBI) encompasses the clinical entity of concussion. Concussion is defined as a trauma induced alteration of mental status with or without loss of consciousness.
Considerable research has been published regarding concussion and recently more research has been published about the multiple blows to the head that occur in all levels of football in the absence of a recognized concussion. These "sub-concussive blows" have become the target for various types of brain imaging and cognitive function testing and the results have raised concern about the long term effects on the brains of highs school and college players.
Some of what we know is :
1.While conventional MRIs and CTs in concussed high school and college football players are normal , Diffusion Tensor Imaging (DTI) and functional MRI have shown abnormal findings some of which may persist for weeks or months. Additionally subtle impairments of verbal memory and other cognitive tests have been reported in concussion cases persisting past the time during which the player has any symptoms.
2.Similar imaging findings and cognitive testing results are being reported in high school and college players after a season of participation in football even thought the players had no reported concussive event.
3.We know that football helmets do not prevent concussions.
4.We know that at least some college level contact sport athletes decades later show abnormal white matter by Diffusion tensor imaging and lowered test results on neurocognitive testing
Some of what we don't know is :
1.We do not know what pathological changes underlie the imaging findings. Do the scan results indicate transient damage and tissue repair without likely long term sequelae? Is there a recognizable subset of these players with these findings who if they continue to be exposed to multiple head blows over many years will develop Chronic Traumatic encephalopathy (CTE)? How can those who may be destined to develop CTE be distinguished from the vast majority of players who never will have those problems
From the wide range of head hit exposures in those NFL players who have been diagnosed with CTE the obvious implication is that there must be a fairly wide range of thresholds. There are reports of NFL players with as little as five years of play showing typical pathological findings at autopsy. Further there has been at least one case of a college player diagnosed with CTE.
2.the long term cognitive changing on various tests and brain imaging abnormalities have been demonstrated in contact sport athletes in college and high school who did not experience a concussion.
Another high school football season is ending and so far we have reports of11 fatalities. This is about average for the years following the meaningful changes made in the rules and the techniques of blocking and less dangerous ways to tackle. Better helmets probably prevent skull fractures but not concussions.
You see the same parents who carefully made sure their kids did not ride tricycles without wearing helmets are some of the same ones watching and yelling at Friday night football games and do not see the irony of the common practice of there being an ambulance at the stadium. If their son is the victim of the second hit syndrome, probably an ambulance won't help.
addendum: Change made on 11/20/15 on the Numbers of high school football reacted deaths and typos corrected on 6/13/16