The doctor says, "Go into the room and, if your wife has her back to you, just say something in a normal voice and move forward saying the same thing until she hears".
So the man goes home and, finding his wife at the kitchen sink with her back to him says, "What's for dinner dear?".
No reply, so he moves forward and says again, "What's for dinner dear?".
Still no reply.
Moving closer still he says again "What's for dinner dear?".
Still no acknowledgement.
He then positions himself just a foot behind her and again says "What's for dinner dear?".
She answers -
Spoiler: