I just read about this today"
"Researchers have identified a potential new sign of concussion in athletes, particularly football players, that can easily be spotted on the field, indicating the need for immediate removal from the game and evaluation for potential traumatic brain injury (TBI).
Spontaneous Headshake After a Kinematic Event (SHAAKE) refers to the rapid, back-and-forth head movement athletes exhibit following a blow to the head. This voluntary motion typically occurs within seconds to minutes after impact and is a familiar response in athletes.
In a recent survey, 7 out of 10 adult athletes recalled making this movement after a collision, and three out of four times they attributed this back-and-forth head movement to a concussion. The association was strongest among football players, who reported that over 90% of SHAAKE episodes were associated with a concussion.
The results were published online on October 23 in Diagnostics."
I thought this was interesting. I will be watching for it in future games.
Now, granted, this is only to assist in diagnosing a concussion. It does not address when to clear someone to play football again, if ever.