Rumor has it that Beethoven conducted the premier of the 9th. Nobody outside of his family and closest friends knew he was deaf. Well...the symphony was a success...but after the piece was over Beethoven kept conducting...unaware that the piece was complete. Somebody had to come up to the podium and stop him. This is when people realized......
As I understood the story, he knew the piece was done, but couldn't hear the applause. Someone had to turn him around to see it. It doesn't make sense that he wouldn't know that it was done, because the conductor can see all the musicians and would know if they were done.(the musicians would have put down their bows and so forth)