Yeah; it does cause memory impairment just as all stimulants do at RECREATIONAL level.
MDMA can cause much more than memory impairment, in fact it overstimulates the brain so much it can kill neurons; thus slowing communication within the brain itself.
I abused quiet a few things heavily for a few years, and I'm great (3.9 GPA in Graduate school for political engineering)
One of the lucky few.