Post-concussion syndrome
About 10% of people with PCS develop sensitivity to light or noise, about 5% experience a decreased sense of taste or smell, and about 14% report blurred vision. People may also have double vision or ringing in the ears, also called tinnitus. PCS may cause insomnia, fatigue, or other problems with sleep.
Concussions in American football
This 2011 study measured a total 753 impacts among these seven players with a median impact of 15g. It did, however, observe 38 impacts of 40g or greater, and six impacts of greater than 80g. Fortunately, none of these youth players experienced a concussion. There is also a concern that since many young players have less developed chest and neck muscles than older players, almost every impact potentially acts likes a surprise hit.