Child won't talk while helmet is on

[Guest guest]

My grandson is 7 mo. old and has just gotten a helmet to correct his

plagio. It has already started working and we think that it's

wonderful but he won't " talk " when his helmet is on. He was saying

DaDa, Mama and Bubba before he got the helmet and now when it's on he

is very quiet. He will smile and giggle a little with it on but once

you take it off he becomes wild man! He really comes alive, " screams "

and says many different sounds. I'm guessing that it just sounds weird

to him when the helmet is on but don't know for sure. He has been

wearing it for a month now and I really thought he'd get over the

strangness but no change yet. Dr says they have not seen this type of

reaction before. We are worried it may effect his speach. Has anyone

had this happen to their child?