I'm not sure if this is the same thing but sometimes, usually when I've been staring at a computer screen for a while, I'll have a sort of brain glitch. It feels like my brain reboots. It sounds sort of digital. Not static, not a roar or explosion, not a voice. A very artificial sounding noise, like your mp3 player just had a bug or like a sound effect from a scifi movie. It's only a split second. I think I lose vision, but it's not like everything goes black, it's more like the input just stops being processed. I don't think I physically jerk. Afterwards I feel a little startled and very awake, but that may be adrenaline from the surprise of it.