The invisible wound
A blast doesn't have to knock you out to hurt you. The pressure wave alone can shear and strain brain tissue — the "invisible" part of the invisible wound.
Repeated low-level blasts — breaching, artillery, heavy weapons — add up, even without a single dramatic concussion. Many veterans never got a diagnosis for injuries that were very real.
Takeaway
Blast pressure can injure the brain with no knockout — and repeated small blasts accumulate.