Accuracy Of In-Situ Audiometry Versus Traditional Audiometry For First Fit Hearing Aid Fittings

The gold standard for adjusting and verifying the accuracy of hearing aid fittings is to perform real-ear measurements, which takes place after traditional audiometry (Valente, 2002). Audiometric thresholds are used to generate prescribed amounts of gain in the hearing aid, which reflect how much the levels of environmental sounds are increased to treat a patient’s hearing loss. Real-ear measurements are then used to verify that a patient’s hearing aid is delivering the correct amount of prescribed gain. This process is often referred to as verification because the goal is to verify that the hearing aid is delivering the correct amount of gain to the patient’s auditory system. In order to obtain real-ear measurements, a probe-tube microphone is inserted into the patient’s ear canal near the tympanic membrane, and the hearing aid is then placed on the patient. The measurement from the probe microphone placed in the ear canal is compared to a measurement taken from a microphone that hangs just inferior to the patient’s pinna, outside the ear. By comparing the sound outside the ear to the sound within the ear canal, the real-ear system is able to calculate how much the hearing aid is increasing the sounds in the environment, which is known as real-ear aided response (REAR) (Valente, 2002). Obtaining REAR is an essential part of the verification process because it ensures that the patient’s hearing aid is providing enough gain to allow access to conversational speech (Valente, 2002).