Auditory Evoked Potentials (AEPs) and Brainstem Auditory Evoked Responses (BAER or BAEP)

Abstract

AEPs reflect the sequential activation of the VIII nerve (N. acusticus). Thus, all elements of the auditory brainstem pathway can be monitored (BAER). In this modality, a square wave pulse is emitted by an electromagnet through earphones (click stimulus) of 100–200 µsec duration. The response waveforms as they are recorded by the electrode montage (active = earlobe on the same side as the stimulus = ipsilateral; the reference electrode on the vertex = C_z; the grounding on the fronthead = FpZ) results in seven characteristic peaks which more or less can be attributed to specific sites of origin along the primary auditory pathway (Fig. 103).