Driver side sun visor came loose and swung down into my head
 

I've used the sun visor quite a bit over the years and today while I was about to pull it to the side to block sunlight from the side window, the clip that latches the visor to the headliner came off. So the visor quickly swung down and into my face/head.

Like a typical visor it's what I am assuming is a a really hard plastic covered by thin cloth. Definitely startled me and gave me a bit of a headache.

Are these capable of causing an mTBI, or is a subconcussive type impact more likely?

Look back though your past posts and the replies..
In Dec 2019, you had a visor incident also.

keeponmovin,

Really...... Rethink your question and that event.