The patent is for "an earring that flashes in synchronism with the wearer's heartbeat."
The earring can detect medical conditions -- a syncopated flash for arrhythmia, I suppose -- but the inventors recommend the device for "a lover . . . [who wants] to determine when his or her partner is excited by observing the rate at which the partner's earring flashes."
Probably a fairly good lie detector, too.
A New York Times article lists an array of interesting inventions -- patent 6,277,079 among them.