Originally Posted by
billew
A concussion is a TBI.
They are two separate things. In this case he had a CT scan to check.
It is possible to have a concussion without a TBI.
It is also possible to have a TBI without a concussion.
It does not follow that the helmet protection failed, any more than it follows that vaccination failed because I got a mild case of COVID.
In both cases, the success is preventing a more severe outcome.