A very serious (and highly misunderstood) symptom of
Sensory Deprivation Disorder -- itself a symptom of Autism Spectrum Disorder -- where a person gets too overwhelmed by the world around them, causing extremely irrational behavior.
The most common cause is too much noise, especially the sounds of multiple people talking at once. However, one
loud talker (or one loud, irritating sound) is usually enough to trigger it. When a person is going into
sensory overload, they will usually exhibit signs of extreme distress, such as clutching their head to shield their eyes and/or ears. They may become extremely irritable, lashing out at just about anyone. They may also wince or flinch if it comes on suddenly.
People who suffer from it often describe the feeling as though they are being attacked, and that their mind is so clouded that they lose all rational thought. And of course, being a symptom of autism, there is no cure.
If you see someone exhibiting these symptoms, especially the wincing, you should immediately shut the fuck up and make sure everyone in the room does so too. The only way to stop a bout of sensory overload is for everything to be totally silent for about 15-30 minutes.
If you want to know what
sensory overload feels like, listen to the music that plays during the Death Egg Zone in Sonic 2, before the two final bosses. Everything feels
terrifying and
distorted, while your mind is just trying to calm down and pretend that everything is okay when it's not.
It's a very real disorder and it deserves more attention.