If you have ever seen a child rapidly flapping their hands or rocking back and forth, you may have wondered what it means.

Researchers at Princeton University and the Simons Foundation have identified four clinically and biologically distinct subtypes of autism, marking a transformative step in understanding the condition ...

Repetitive motor behaviors (RMBs) such as hand flapping and rocking occur in more than one third of toddlers who do not meet diagnostic criteria for autism spectrum disorder (ASD), with higher rates ...