I have a 9yr old son who has CP and mr/dd.
my son was diognosed with hyperacusis from a very good audiologist. He now wears sound generators and not only did his behavior change for the better, not perfect due to all the other things he has, but we can go to noisy environments now without meltdowns.
One thing make sure you do not wear earplugs as this will make things worse for sensitive ears. I do not have time right now to explain hyperacusis, but if you google it you will find great info. about it.
After many many complaints to the ped. i think she finally just resorted to an audiologist, my ped. seemed to know exctly what hyperacusis was after the diognosis, but actually sent us for CAPD testing. The audiologist said it sounds like you are here for something different, but I said he shows signs of CAPD also. So he has a form of CAPD and hyperacuis.