I hope it's the just the B-12 deficiency. One thing I've noticed from having two grandparents with serious alzheimers is that their memory loss starts with short term memory and progresses towards long term. For instance, in the beginning, my grandmother may not have remembered what she had for lunch the day before, but otherwise was pretty much with it. Some time later (many months), she may not have remembered people's names right away, but could recognize faces and associate who they were (friends, sons, grandchildren, ect). After that, it went onto she didn't recognize people (like me) at all but she remembered her friends from childhood, the name of the street she grew up on, ect. Now she pretty much is completely out of it. This took probably 3 or 4 years.