A new approach for recording distortion product oto-acoustic emissions.

A system for recording of distortion product oto-acoustic emissions (DPOEs) utilizing a linear time-averaging technique is described. The main advantage of the system is the ability to obtain a high signal-to-noise ratio of the recordings. DPOEs have proven to yield important frequency-specific information on the behaviour of the outer hair cells in the human inner ear. DPOEs at nine audiometric frequencies, elicited at a stimulus intensity of 75 dB SPL were recorded from a group of 14 normal-hearing subjects in an attempt to establish normative data. An example of the relationship between the configuration of the conventional audiogram and DPOEs for a patient with a noise-induced hearing loss is presented to demonstrate the diagnostic value of the method.