Have a look at this patent :
www.freepatentsonline.com.../6488617%2520OR%2520U.S.%2520PATENT%2520%2520#%206488617&stemming=on
TITLE: Nervous System Manipulation by EM Fields from Monitors
Issued to: Loos, Hendricus
Abstract: Physiological effects have been observed in a human subject in response to stimulation of the skin with weak electromagnetic fields that are
pulsed with certain frequencies near 1/2 Hz or 2.4 Hz, such as to excite a sensory resonance. Many computer monitors and HD TV screens, when
displaying pulsed images, emit pulsed electromagnetic fields of sufficient amplitudes to cause such excitation. It is therefore possible to manipulate
the nervous system of a subject by pulsing images displayed on a nearby computer monitor or DIGITAL TV set. For the latter, the image pulsing may be
embedded in the program material, or it may be overlaid by modulating a video stream, either as an RF signal or as a video signal. The image displayed
on a computer monitor may be pulsed effectively by a simple computer program. For certain monitors, pulsed electromagnetic fields capable of exciting
sensory resonances in nearby subjects may be generated even as the displayed images are pulsed with subliminal intensity.
USP # 6,488,617 (December 3, 2002)