Auditory Evoked Potentials

Abstract

This chapter presents an overview of auditory evoked potentials (AEPs). AEP studies are important in rehabilitation medicine, as clinicians often treat patients with major functional deficiencies such as incoordination and deep sensory involvement, and ataxia and balance problems. The most useful classification of AEPs is based on latencies. The early—short and very short—AEPs are recorded in the first 10 ms and include the most clinically useful, brain stem AEPs (BAEPs). In addition, the early AEPs include the very short electrocochleogram (ECochG) components and the similarly short frequency-following response (FFR). The middle latency AEPs are not used routinely in clinical practice though they have some relevance in cortical deafness or coma. They range from 10 to 60 ms and include the neurogenic middle latency responses (MLR) and the myogenic or sonomotor responses. Unless the subject is completely relaxed, as a rule, MLRs are masked by the myogenics. The long and very long latency AEPs range from 60 ms to a few seconds.