Book Description

The three manuscripts presented here examine the role of acoustic and electrically evoked potentials to assess sensory and neural encoding processes by the peripheral auditory system in hearing-impaired listeners. The first manuscript defined how spectral and temporal properties of the phonemes /da/ and /ba/ were encoded in the peripheral auditory system using electrocochleography (ECochG) in normal and hearing-impaired listeners. Results suggest that the fundamental frequency of each phoneme is the dominant spectral content encoded by the peripheral auditory system. Additionally, spectral encoding by the sensory cells of the cochlea, as measured by the cochlear microphonic response, is strongly correlated with word recognition performance. In the second manuscript, acoustic click train stimulation was employed to study the impact of M%eacute;nière’s disease on two temporal response properties of the auditory nerve: adaptation and recovery from adaptation. The findings of this study suggest little evidence of neural damage in Ménière’s disease that exceeds that of other forms of sensorineural hearing loss. Finally, in the third manuscript, electrical stimulation of the auditory nerve was utilized to investigate the effect of aging on the response properties of the auditory nerve. The sensitivity of the auditory nerve to steady state pulse trains was not found to be significantly different between older and younger adult cochlear implant users, although trends of poorer function in older adults did exist, especially at higher pulse rates. Results suggest potential negative effects of aging on temporal response properties to electrical pulse train stimulation at high pulse rates. Overall, evoked potentials provide a robust technique to objectively study processing of the auditory system in normal and hearing-impaired listeners.