Description of the EABRs

EABRs could be recorded in all subjects but wave IIIe was missing in Subject 1 (when the response was evoked by electrodes 3, 5, and 16), Subject 6 (for electrode 16), and Subject 7 (for electrodes 6, and 13). Wave IIe and wave IVe were present in some recordings, while wave I could not be recorded as it was masked by the electrical stimulation artifact. The morphology of the EABR recordings was consistent with other reported EABR findings (Shallop et al., 1990; Brown et al., 1990, 1994; Mason et al., 1993; Gallégo et al, 1996; Firszt et al., 2002). Figure 2 shows the EABR recordings for all three intensities on electrode 4 in Subject 2. Individual waveforms recorded from all eight subjects on electrode 7 are displayed on Figure 3.

Figure 2. EABR measures recorded from Subject 2 on electrode 4 (apical electrode) at comfortably loud intensity. A stimulus artefact is present within the first 0.8 ms after stimulus onset. Waves IIe, IIIe and Ve are indicated.

Figure 3. Averaged EABR waveforms recorded at comfortably loud intensities on electrode 7 (medium electrode) from all eight subjects. Waves IIIe and Ve are indicated. The subjects scores to speech perception test in quiet (voice at 65 dB HL) at three months of cochlear implant use are indicated. A stimulus artefact is present within the first 0.8 ms after stimulus onset.