It is mostly research on syndromes-like sandifers and 2 others I can remember; but from what I’ve heard its how severe the children got the symptoms and how long they had the symptoms and if the symptoms affected their ability to learn, reasoning is if you are in pain that is what you will concentrate on. But there was no conclusive evidence if it did or didnt cause developmental delay. I will be going to another conference in June, I’ll bring back an update then.
Funny thing is I did not pay much attention until I had my daughter and she started spitting up and then got severe reflux, and she started having Developmental delays such as sititng up and she never did like tummy time-reflux related?