I don't know for sure but I do know that we have differing strengths in the ways our memories work.
ie If I want to get somewhere, you can explain it to me verbally (this only applies b4 my accident) and I will mb every detail because I can mentally visualise what you are saying.
Someone else on the other hand, may need you to draw the directions out on paper or still, write them down.

What I am saying is that the memory part of our brain must be split up into sections for mental visualisation/images and mb names or roads in the form of worded facts.