Musannaf Ibn Abi Shayba 18:174

Abu Bakr narrated to us, he said: Muhammad ibn Bakr narrated to us, from Ibn Jurayj, he said: It reached me that a man came to Umar ibn Abd al-Aziz and said: "So-and-so struck me until one of my ears became deaf." He said: "How shall we know?" He said: "Call the physicians." So he called them, and they smelled it, and they said: "This is the deaf one."