Auditory evoked potentials: basics and clinical applications

Abstract

Auditory evoked potentials (AEPs) are elicited at various levels of the auditory system following acoustic stimulation. Electrocochleography is a technique for recording AEPs of the inner ear. The recording is performed by means of a needle electrode placed on the promontory or non-invasive with tympanic membrane or ear canal electrodes. Clinically, electrocochleography is used for the diagnosis of auditory neuropathy spectrum disorder (ANSD) and endolymphatic hydrops. According to their latencies, AEPs of the central auditory pathway are subdivided into early, middle and late (cortical) AEPs. These AEPs are recorded via surface scalp electrodes. Normally, the larger EEG masks AEPs. For unmasking the AEP, several techniques are applied. Early AEPs or auditory brainstem responses (ABR) are the most widely used AEPs for functional evaluation of the auditory pathway. In contrast to otoacoustic emissions, early AEPs can detect ANSD. Thus, they are more suitable for hearing screening in newborns. For this purpose automated procedures are implemented.