My son screams and hums all day long. He seems happy when he's doing it so I let him. If it's really starting to work my nerves then I'll sing with him to kind of guide him toward that activity. He doesn't scream in public so I don't think it's sensory overload in his case. It just seems to feel good to him.

My 4 year old does and I've been told by other parents they can "outgrow" it with a lot of reminders to be quiet. She mostly does t when she's over stimulated and excited/happy. Like when in the iPad or watching tv.

Looks like I'm not alone as well. My 2 year old has started doing this recently. He's got quite the lungs but this really does sound like he's hurt. He isn't though but that scream is a loud shriek. Lol. Drives me crazy and I do agree with KeriSuePauline , could be attention seeking or sensory overload behavior. He doesn't do it often so I know it's one or the other.

My daughter sounds like she's being murdered half the time! It's very upsetting for me! She's nonverbal so i try to figure out what's wrong and calm her to the best of my ability! I see I am not alone!

My 5 year-old daughter still screams loud enough to make my ears ring. She is somewhat verbal but she enjoys echoes and getting a reaction out of people. She didn't do it much until she was the only girl in a class of mostly non-verbal ASD boys. She picked up more of the hand flapping.