I live in an old row home that was made into two apartments. So no insulation at all. Just a house with two different front doors.
I can hear the upstair neighbor walk, shower, talk on the phone, listen to music...well, everything. But I remember that when my little one wakes in the middle of the night...screams from teething, gets loud cause, well, shes a kid, whines, cries...etc, etc...he hears that. So I figure it's tit for tat. Your little one will only get louder, remember that. It sucks, but not much you can do.