An apparatus that can be used to detect concussion causing forces in an athlete contains a mouth guard, a plurality of force-sensitive visual indicators, and a plurality of transparent covers. The plurality of force-sensitive visual indicators is used to indicate the occurrence of a significant impact. When the apparatus is utilized, the athlete places the upper set of teeth in a teeth-receiving channel of the mouth guard. When the athlete experiences a significant impact, the plurality of force-sensitive visual indicators is activated. Since the plurality of force-sensitive visual indicators is enclosed within a U-shaped body of the mouth guard, the athlete or another observer can get an understanding of the severity of the impact by examining the plurality of force-sensitive visual indicators. In particular, the plurality of force-sensitive visual indicators is examined through the plurality of transparent covers.