Any concussion is by definition a brain injury. Any brain injury is, by definition, damage to the brain. And we know that brain damage has an uncertain prognosi

Any concussion is by definition a brain injury. Any brain injury is, by definition, damage to the brain. And we know that brain damage has an uncertain prognosis - it may or may not ever heal in any meaningful way, and might even get worse over time. People handwaving around how much worse it gets under x or y circumstance just don't like the way the math adds up: brain injury is cumulative and progressive regardless of severity, age, repetition, or any other factor.