first of all I will be hoping that you will have a successful and safe surgery next week.
chiari is a very mysterious thing...nobody seems to have all the same symptoms.I have had memory/cognitive issues,but that all got better after I started getting B12 injections(due to a B12 deficiency).so I really don't think the chiari is the culprit as far as memory/cognitive issues are concerned.
the rsults from the decompression surgery are different for each person.you might want to read some older posts from Derrick on this board(he had that surgery in September this year)...he posted back only once after his surgery....and he was still recovering....so we have no idea how he is now.
I only know one person who had the surgery and she was up and about a couple weeks after her surgery.
I wish you a speedy recovery and best wishes and prayers that you will get thru this and have much better health.