Among other factors, it depends on the specific memory issues a person is having having (short-term vs long-term, recall issues, transient amnesia, muscle memory, visual memory, procedural memory, etc.). Some issues can be caused by meds and will improve when the meds are reduced or stopped, but not in every case or for every person.
When I was on zonisamide, I had started having problems with word-finding -- a cognitive function related to memory recall. When I went off the Zonisamide, that problem went away.