Distortion in big screen TV

A friend of mine just bought a large screen lcd type TV and get a bending and twitching of images on the top of the screen. Has anyone seen this and know what it is?
Are your speaker shilded?
if not try to put them wider
Good Luck!
also could be anything magnetic or electromagnetic in proximity.....ie...magnetic latches on entertainment centers....what's in ceiling above or in wall at that height (of electrical nature)?...although like the last response it sure sounds like a magnetic field like from an unshielded speaker