write down all the things your son is doing, that is date time what happened immediately before, describe the action/melt down - how long it lasted, what he did and how he was after it. for actions also include his reaction to interruptions. once you have a good list of things add a note about your concerns and what you would like them to look into then at the next meeting hand it to his paediatrician. that way your concerns and his actions will be there in black and white for the pedi to see even if you are distracted at the time.