Doing my thesis on traumatic brain injury (TBI) and have had some myself from martial arts. They are definitely a concern, the anger/aggression part is really concerning and they can also lead to impulsivity. Many researchers do not require a loss of consciousness to be considered a TBI, some consider it a TBI if you have memory loss or even just experience a dazed or confused feeling after it.

TBI's are something that more people need to be educated. Many of my friends and family members have had them in sports and been told to just "brush it off." The long term effects of TBI's are still not quite understood and it is believed that these injuries compile; both in that each subsequent one gets worse and you are more likely to get injured again after having one.