This was particularly interesting for me, as my dad suffered a closed head injury during WWII. He was in a coma for weeks and had to learn to walk and talk again. He went on to live a fairly normal life, but in his 70s fluid began to build up behind scar tissue left by the injury. The operation to put in a shunt - generally very successful - failed and he went into a severe dementia which lasted ten years until his death. Most cases work out, and the fluid would have drained, leaving him "himself." He was, unfortunately, one of those for whom the surgery went bad. The result was devastating. His type of dementia was occasionally like Alzheimer's, but often very different. Thanks for this interesting approach, Christine.