Autism spectrum

Hi My baby is 7 months and recently she started arm flapping and twisting at the wrist. She often screams & stiffen her arm,legs and body.Otherwise she’s achieved all other milestones of her age. She smiles,plays with me,identify familiar sounds,good eye contact & sits without support.Should I be worried about the flapping/screaming/stiffening?Kindly advice

My 5 month old daughter some times flaps her right hand for 2-3 seconds. We have read that flapping hands are a sign of autism and hence feel worried. Should we?

My 7 month old does finger flicking a lot on surfaces such as toys, clothes, my neck when held. sometimes in air too(rarely) Is it something to be worried about?

My almost 3 years old son has recently ben diagnosed with autism spectrum disorder. He only says a handful of words. So im trying to learn ASL (sign language) and trying to teach him. Any one have tips tricks hacks that made communicating with your child easier!