Auditory evoked potentials from the cortex: audiology applications.
PURPOSE OF REVIEW: The audiological applications of cortical auditory evoked potentials are reviewed. Cortical auditory evoked potentials have some advantages compared with more commonly used techniques such as the auditory brainstem response, because they are more closely tied to perception and can be evoked by complex sounds such as speech. These response characteristics suggest that these potentials could be used clinically in the estimation of threshold and also to assess speech discrimination and perception. RECENT FINDINGS: Clinical uses of auditory evoked potentials include threshold estimation and their use as an electrophysiological index of auditory system development, auditory discrimination and speech perception, and the benefits from cochlear implantation, auditory training, or amplification. SUMMARY: Cortical auditory evoked potentials obtained in passively alert adults have a remarkably high correspondence with perceptual threshold. Acoustic features of complex sounds may be reflected in the waveform and latency of these potentials and so might be used to determine the integrity of neural encoding for such features and thus contribute to speech perception assessment. MMN and P3 have been used to discern discrimination abilities among groups of normal-hearing and hearing-impaired individuals; however, their sensitivity and specificity for testing an individual's abilities has not yet been established. Cortical auditory potentials are affected by listening experience and attention and so could be used to gauge the effects of aural habilitation. The presence of cortical potentials in children with auditory neuropathy appears to indicate residual hearing abilities. Parametric and developmental research is needed to further establish these applications in audiology.