If you’ve never heard the scream of an autistic child, count your blessings. It’s inconceivable how a single, shrill sound could convey so much pain, confusion, and anger. The scream comes from so deep inside them it sounds more animal than human. And yet, it’s so shrill and hollow that it’s ethereal.

Often words are woven into the scream — “I hate you!” or “Get away from me!” — to produce a genderless voice. Add the repetitive nature of what they’re screaming and it’s not difficult to see how this could have once been labeled “demon possession.”

Autism, in the time of a rage, wipes away all differences between afflicted children — gender, intelligence, everything — and replaces it with a screech. The rage contorts the face, flails the limbs, and lashes out at anything in the vicinity. The scream fills whatever space you’re in, seeming at times almost like another entity, hovering around the child as you try to isolate her so that so can calm herself.

If it happens around children who are not accustomed to it, the bewilderment and pity in their eyes is striking. And it’s impossible to deny the spark of fear as well.

Often the screaming subsides as quickly as it comes on. A raging child might notice there’s an echo in the room where he is, and that will be enough to derail the rage and pacify the child.