I agree with many here that the idea of the brain not being able to fully recover is upsetting, and seeing posts on this board, many from you Mark, about how once concussed, always concussed, and that stress will likely bring out symptoms even if they go away, has caused a lot of distress for me. I loved who I was before the injury, as I'm sure everyone here also did, and the thought that that person is gone forever is profoundly upsetting.

So, I'm wondering (and I don't mean to sound accusatory here, I'm not trying to be!) how you (or the field in general) know this? That is, what is the evidence that a single, mild concussion leaves permanent damage that can always rear it's ugly head if we stress our brains? I understand that if there is structural damage, this likely will always be there, but whether or not that damage results in a permanent functional deficit (or propensity for such a deficit with stress) seems harder to demonstrate definitively.

Are there studies that have demonstrated this? Or is this just the consensus of the field, or your personal experience having been an elder on the board for a while and being very knowledgable about TBI in general?