Discussion

A primary goal of this study was to record the ELARs and to characterize their latencies with regard to the effects of electrode location and deafness characteristics, i.e. duration of deafness and degree of hearing loss. Late evoked potentials were thus elicited through stimulation on four intra-cochlear electrodes across the implanted array with stimulation delivered at the most comfortably loud level in 14 subjects. This investigation, being concerned with the central level of the auditory pathway would complete a previously conducted (in press) study concerning the effects of the auditory pathway anatomy versus deafness characteristics on the latency of EABRs. The same protocol was used in this EABR study, which showed a decreasing baso-apical latency gradient for waves IIIe and Ve. The latency of waves IIIe and Ve also decreased for shorter duration of deafness and better audiometric mean before implantation and showed a global decrease with lower M levels.