Concussion grades and definitions
Guideline	1	2	3
Cantu5	No loss of consciousness	Loss of consciousness for fewer than 5 minutes	Loss of consciousness for more than 5 minutes
	Post-traumatic amnesia for fewer than 30 minutes	Post-traumatic amnesia for more than 30 minutes	Post-traumatic amnesia for more than 24 hours
Colorado Medical Society6	No loss of consciousness	No loss of consciousness	Loss of consciousness of any duration
	No post-traumatic amnesia Confusion	Post-traumatic amnesia Confusion
American Academy of Neurology7	No loss of consciousness	No loss of consciousness	Loss of consciousness of any duration
	Concussion symptoms for fewer than 15 minutes	Concussion symptoms for more than 15 minutes