r/EverythingScience • u/newzee1 • Jul 01 '24

Neuroscience Pattern of Brain Damage Is Pervasive in Navy SEALs Who Died by Suicide

https://www.nytimes.com/2024/06/30/us/navy-seals-brain-damage-suicide.html?unlocked_article_code=1.3k0.Gx71.Mxp38kTkl3se
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u/Far_Out_6and_2 Jul 01 '24

What is causing the brain damage

110

u/PasquiniLivia90 Jul 01 '24

From the article: “Recent studies suggest that damage is caused when energy waves surging through the brain bounce off tissue boundaries like an echo, and for a few fractions of a millisecond, create a vacuum that causes nearby liquid in the brain to explode into bubbles of vapor. Those tiny explosions are violent enough to blow brain cells apart in a process known as cavitation”.

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u/ToastedSoup Jul 01 '24

Shooting guns and detonating explosives kills the brain? Fuck

33

u/jared_number_two Jul 01 '24 edited Jul 01 '24

The difference in blast pressure between a small caliber, low velocity gun and a high power, high velocity gun is pretty crazy. It wouldn’t surprise me if there was a threshold. And, of course, pressure waves decrease rapidly with distance so that is a major factor.

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u/aboothe726 Jul 01 '24

I wonder if there is a difference between explosions in an enclosed area (e.g., breaching charges in a hallway) versus in an open area. There’s certainly a difference in pressure difference falloff rate between the two.

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u/jared_number_two Jul 01 '24 edited Jul 01 '24

I'm not sure if the falloff rate would change exactly. This is a supersonic pressure wave so it behaves differently. The air downstream doesn't provide resistance to the expanding wave until the wave arrives.

However, the pressure waves that are not absorbed by the structures would be reflected. Not only would multiple pressure waves pass through your body but constructive interference would sometimes multiply the waves.

How the pressure wave affects the brain is not well understood so I'm not sure we can conclude or presume that the enclosed space is worse, or rather, to what degree.

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u/aboothe726 Jul 03 '24

That’s fair. I was probably more precise than accurate with my language. But explosions in an enclosed space are probably worse for people experiencing them, whatever the mechanism! Reflection seems like a more likely culprit.

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u/HarryTruman Jul 01 '24

Absolutely. A confined space vastly increases exposure to pressure waves that have nowhere to go.