As you get older your brain is more vulnerable to anesthesia.   It is more likely you might suffer from at least two conditions that affect your mental functions.

Post-op Delirium

The first is Postoperative Delirium which tends to be a temporary condition that may not develop until a few days after surgery.  The patient can become confused, disoriented, have problems with memory and not be aware of their surroundings.  Fortunately, this disappears within a week.

Cognitive Dysfunction

The second condition is Postoperative Cognitive Dysfunction.  This is a more serious condition as it can lead to long-term memory loss and affect your ability to learn, concentrate and to think.  It is important to obtain a baseline memory function before undergoing surgery.

Prepare in Advance

It is important to talk to your anesthesia provider before your surgery with your concerns and to obtain one that specializes in the care of the aged.  It is also important your caregiver who spends the most time with you be with you to observe for any significant changes in your mental condition.  An additional factor is that medications can affect your mental function and these should be monitored by your physician.