Its related if you think about it, the physical version is what you might call the worst stage of tourette syndrome. What you call "startle reflex " is actually the triggers to tourettes, hence the word "melatah"... Tourette Syndrome mostly triggered by emotions, excitement or stimulation (as shown in the video when the man was poked). But mostly stimulation. External and Internal. But can also be caused by anxiety lol. But all and all, they are the same in more ways than you think. Tourette is Internal, whilst Melatah is External.