Television has traditionally been the most common source of seizures in PSE. For people with PSE, it is especially hazardous to view television in a dark room, at close range, or when the television is out of adjustment and is showing a rapidly flickering image (as when the horizontal hold is incorrectly adjusted on analog television sets). Modern digital television sets that cannot be maladjusted in this way and which refresh the image on the screen at very high speed present less of a risk than older, analog television sets.