It's interesting, or I found it so, that the term TBI actually dates to the 1800s, and shell-shock did not come into use until 1915. And the cause-effect relationship between physical injury to the head and cognitive and/or behavioral impairments was known even a couple hundred years before that. I'm not saying they knew the why, but they noticed that "John gets hit in the head a lot and he doesn't speak well/gets mad easily/doesn't remember anything we tell him."
You're also spot on, IMO, about artillery fire and explosions scrambling guys brains. From what I recall of the more recent research, those consistently exposed to small arms fire show significant evidence of repeat TBI and CTE (Chronic Traumatic Encephalopathy). As another poster mentioned, the advent of very effective brakes is likely to increase these effects. It's on here already in different threads, guys talking about they have multi-hour headaches after a range session with a braked rifle. You probably have a mild TBI....
Basically anything that bounces your head and brain around, is not good for you. Dale Jr. retired from NASCAR because he had so many concussions, both more traumatic ones from wrecks and many, smaller ones, or sub-concussive impacts, just from riding the car around the track.
Many youth soccer leagues have banned heading the ball until like 14 yes old or so, due to CTE risk.
I watch a lot of MMA, and love it as a sport, but some of those guys are in for a rough time. Tony Ferguson, Justin Gaethje, Bryce Mitchell had a seizure in the octagon immediately following his last knockout.
Didn't mean to write a novel, I get talkative I guess.
