Sorry to hear about your accident Dan and I certainly hope you make a full recovery and in less time than the last one. As far as your memory goes hopefully it too comes back. At least you remembered how to log on and where your friends are. That's a good start and if you remember to bring tent poles to the next MD. well than we'll know your memory came back better than ever.
Sadly all the book learning, videos and years of experience, will not prepare you as much as constant practice and getting to know the feel, of the specific bike your riding and its limitations, to the point were it almost becomes a part of you. Even then circumstance, still plays a key role. You can remain as alert as an owl 99.9% of the time and yet that one split second, your attention is drawn elsewhere, you still could be trouble.