I had same issue from the sound of it. Turned out to be interference from another wireless device.
It just started happening one day. Then it would stop, get worse, get better. Driving me nuts. Then one day it just completely choked and stopped working (stopped moving on the screen).
That was when I heard something outside...my neightbor had one of those remote-controlled RC cars out in the street (quiet street, no traffic) and was zipping it up and down the street. Had no idea they pumped out so much RF trash noise. Sure enough when he stopped playing around and turned off his gizmo then I could use my mouse again. Thankfully he hasn't played with his wireless toy race car for a while.
Moral of the story...suspect interference and be ready for it to drive you crazy until you figure out which neighbor just bought a new wireless telephone for the house or one of those wireless baby monitors.