What Causes Loud Ringing In The Ears?

My husband had a pace maker put in about two years ago. Since then he started having problems. His ringing in his ears gets really loud then he gets burning across this chest and arms. After that he starts shaking real bad and loses all use of his arms and legs. He has a hard time talking. It started happening every few months and now it's almost every day. He is I in the hospital right now for the fifth time for this. Instead of sending him home they did an eeg a
nd cat scan. They showed nothing. Now they don't seem to know what to do. Have you ever run into this