Supplemental Material:
hearing preservation

Adult cochlear implant (CI) recipients with hearing preservation experience significant improvements in speech recognition with electric–acoustic stimulation (EAS) as compared to preoperative performance or postactivation with a CI alone, although performance across EAS users remains widely variable (Maps that align the filter frequencies to the cochlear place frequencies, referred to here as Default mapping procedures for EAS devices do not incorporate variability in AID of the electrode contacts, which can result in electric frequency-to-place mismatches that negatively influence acute speech recognition (EAS users may experience better early speech recognition with maps derived from a place-based mapping procedure that eliminates electric frequency-to-place mismatches by incorporating the AID of electrode contacts for individual CI recipients. For example, the place-based mapping procedure used in this report calculated the AID of each electrode contact from the postoperative computed tomography (CT) imaging and estimated the cochlear place frequency. The filter frequencies for specific channels were assigned to match the place frequencies of the corresponding electrode contacts. While this approach eliminates electric mismatches, it can result in spectral gaps that default mapping procedures avoid. Spectral gaps generally result in poorer performance for EAS users (This report assessed the influence of electric frequency-to-place mismatches on the speech recognition outcomes of EAS users within the first 6 months of device use. The study sample included EAS users who were randomized to listen exclusively with either a default map (variable magnitudes of electric mismatch across individuals) or a place-based map (no electric mismatch). The hypotheses were that early speech recognition outcomes would be better for EAS users with smaller electric mismatches and that the negative influence of larger electric mismatches would persist over the initial months of EAS listening experience.