The Harding Test is a set of algorithms that measure the level of rapid cuts, flicker patterns, and strobe effects in a piece footage, and their subsequent ability to induce epileptic fits in susceptible viewers.
It’s a test whose need became readily apparent after a 1997 “epidemic” of seizures that accompanied the screening an episode of the Pokemon series in Japan. (In that particular episode, the seizures were triggered by strobing red lights emanating from the eyes of the signature character, Pikachu.)
Recently, its most notable application was the temporary ban of the video of Gnarls Barkley’s new single “Run” (see the above piece of YouTubery) by British MTV. The supposedly seizure inducing part of the clip appears towards the end when moiré patterns swamp the background and flickering images of the word “RUN” worm their wary into the video.