Regarding concussion: this is dangerously wrong. To be knocked unconscious due to a head blow is by definition a Grade II concussion. The emerging consensus o

Regarding concussion: this is dangerously wrong. To be knocked unconscious due to a head blow is by definition a Grade II concussion. The emerging consensus on brain injury is that even lesser concussions can have severe long term effects, especially additively (see e.g. NFL and NHL brain injury scandals).