<prompt> Otoacoustic emissions are derived from:Tympanic membraneOssiclesCochleaVestibule  <response>: Ans. c CochleaRef: Dhingras ENT 5th ed. 32 Otoacoustic emission OAE are low intensity sounds produced by outer hair cells of a normal cochlea. These sounds produced by outer hair cells travels in a reverse direction: outer hair cells - basilar membrane - perilymph - oval window - ossicles - tympanic membrane - ear canal. When outer hair cells are damaged, OAE are absent. Hence it helps to know the function of cochlea. 