I've also read this thread with great interest and a sigh of relief that I'm not the only one dealing with these issues. Sciencemama, I'd read your posts about selective mutism and saw some things that applied to our situation. DD's now closer to a "slow to warm up" kid than selective mutism but the meltdowns can be awful. Do you have any additional info on this part (bold added)?

Originally Posted by Sciencemama
My daughter with those meltdowns was the one with severe social anxiety as well and selective mutism (a communication disorder in social settings - though she was highly communicative at home). Turns out they had a lot to do with each other, but the common element was a neuro-developmental delay (not a dysfunction or a disorder, just a delay in development) in her emotional regulation centers though her cognitive development was advanced. Or, in other words, she was developing asynchronously and her emotional intelligence (for lack of a better term) needed to be brought up to the level of her cognitive intelligence.

Thanks for this information and the links you provided. I've read The Explosive Child and will look into Nurtured Heart too.