I wish I could see the link so I could thoroughly debunk the idea of fast braking being a concern. The most a braking action can do is cause a 1.5 to 1.7 G deceleration. ABS brakes actually moderate braking force at a means of maintaining traction and steering control.

There is an idea in physics that says in layman's terms: Energy cannot be added to or removed from a process.

The energy on the outside, say the body against the seatbelt is no more or less than the energy inside the brain.

If the car decelerates at 1.5 Gs, the max deceleration the brain can experience is 1.5 Gs unless it impacts something that has decelerated more than the head, like a dashboard or windshield.

That means, if the car stops but you continue to move until you hit the dashboard or windshield with your head, you can experience more Gs with that impact.

I have a limited tolerance for "Yeah but......" claims or questions. The laws of physics regarding weight and motion (I got an A in that college class) do not change. If you are looking for a way to make a rational claim regarding an irrational anxiety, think seriously about your question.

I don't deny that people experience symptoms after these events. Those symptoms do not justify "I think I caused damage to my brain. Should I quit school or my job and wait to become a blubbering idiot?"

Reddit Redidiots make all sort of unsubstantiated claims. Other online forums do to.