Differential Diagnosis of Hearing Disorders — Clinical Findings Contributing to Information Processing in the Auditory Pathway

Abstract

The far-field recording of auditory evoked potentials (AEP) has been gaining importance to neurophysiological, audiological and recently also to otoneurological approaches. Both electrocochleography (ECochG) and recording of early AEPs (brainstem potentials, latency 2 – 10 ms) are highly reliable and independent of subjects’ vigilance; they are important to the diagnosis of cochlear and retrocochlear hearing disorders as far as the brainstem region. Late AEPs (latency more than 50 ms) are reliable only with recording conditions of constant vigilance, preferably in wakefulness. Late AEPs are advantageous in that they may be used to determine hearing thresholds for lower frequencies, while for early AEPs the lower frequency limit is around 1 kHz.