It is narrated from Ibn Mahbub from Abdul Wahhab ibn Al-Sabbah from Ali from Abu Basir from Abu Abdullah Imam Jafar ibn Muhammad Al-Sadiq عليه السلام that he said regarding a man who was struck in his ear and claimed that one of his ears had diminished in hearing. Imam عليه السلام said: "The injured ear should be tightly bound, and the healthy ear should be left open. A bell should be struck in front of his face, and he should be asked to listen. If the sound of the bell becomes faint for him, its position should be noted. Then, the bell should be taken behind him and rung until the sound fades for him; when it fades, its position should be marked. The distance between the two positions is then measured. If they are equal, it is known that he has spoken the truth. Then, the bell should be taken to his right side and rung until the sound fades, and its position should be marked. Similarly, the bell should be taken to his left side and rung until the sound fades, and its position should be marked. If the distances are equal, it is confirmed that he has spoken the truth." Imam عليه السلام further said: "Then the affected ear should be opened, and the healthy ear should be tightly bound. The bell should be rung in front of him, and the process repeated as it was initially done with the healthy ear. Then, the difference between the healthy and the affected ear should be measured, and compensation determined accordingly."