Interesting. Always wondered what the scientific explanation was.
I don't know if a past life could effect it, but if you enter a room where a past life experienced something traumatic, or has a happy memory attached, then you might experience deja vu as a result of a past life.
As a kid I got deja vu a lot, but not so much now. The worst was at my grandparents. I use to have a dream where I would climb over the railing on the second floor and jump [there's an open area that you can see the dining room bellow.] For years when I would enter the dining room from the livingroom [the entrance is right bellow where I would jump in the dream] I had such a bad case of deja vu I would almost fall over.
Some I grew out of it myself, but if it happens a lot and seemingly at random I would see a doctor.