Your character has received a blow to the head. This affects skills and Intelligence.”
The concussed status is displayed in red, in the left low corner of the screen.
Fallout 3 and Fallout: New VegasEdit
Concussion is a status condition caused by having the head critically crippled in combat. Having it will reduce overall accuracy and give a -4 to Perception. In addition, the screen will intermittently get fuzzy and a ring will be heard through the speakers.
It is unknown if enemies really undergo a concussive state when they have their heads crippled. As with the crippling any body part, targets will momentarily pause to clutch their head.
Using a stimpak, sleeping, visiting a doctor, using My First Infirmary (if purchased for the residence), or through some other means relieving the crippled head will remove the effect and restore the Perception.
Crippled Limbs - When an arm or a leg is crippled, affecting character performance.