Concussion is classified as a mild traumatic brain injury (mTBI), the use of the word mild relates to the absence of structural brain damage. Full recovery can occur after concussion; however the brain is vulnerable to permanent damage in this recovery period.
The term ‘mild’ can be misleading as the metabolic and physiologic processes are severe, with potentially severely debilitating side-effects.
At present the research does not suggest repeated concussions lead to long-term issues or brain damage, so long as secondary impact syndrome is avoided, however further research is needed in this area. If there is a secondary impact in the recovery period, there is the potential for permanent damage of neurons in the brain.