Does anybody out there know of anyone who has had an out-of-hospital cardiac arrest?

Does he or she have any permanent neurological damage? If not, how long did it take before you noticed the person was getting better???? My aunt had a V-Fib cardiac arrest. Paramedics had to shoot medicine into her heart to get her going. The paddles didn't work. She was on the vent to help her breath and within 24 hrs of this event, she opened her eyes. Vented for less than 3 days. She is very confused and one minute she knows who I am and the next minute I'm sombody else. Doesn't even know what state she's in, the date, the president, etc. If you show her something - for example keys - she can tell you she unlocks the door with them, but she doesn't know they are called keys. Has anybody experienced any of this and what was the outcome? Thanks for reading my question!