Most of us think of tinnitus as that annoying ringing that happens in one or both ears, even though we know there is no outside noise causing it.  Tinnitus includes not just ringing, but other noise like roaring or hissing or buzzing.  The cause of tinnitus is not known, some people can live with it and find it tolerable and others may find it intolerable and even debilitating. It is somewhat surprising to learn that as many as 50 million...