Dd is 10 months old and has taken to sitting forward in pushchair/highchair and then throwing her head back really hard so that it hits the back of the chair. It looks like it would be excrutiatingly painful, but when I tell her not to do it she laughs! She seems fairly normal and happy in every other way, so I am hoping it is not a sign that she is unhappy. Has anyone had any experience of this? The other odd thing that she does is whenever she is frustrated/confused/bored/angry/excited she twizzles both hands backwards and forwards. She seems completely unaware that she is doing it and never looks at her hands while she is doing this (had heard that if they look at their hands it can be all about judging distance etc.) Is this common? The HV said it could be some kind of neurological disorder but that she doubted this as dd is very bright, happy and interactive. Any ideas?