Purpose: Cochlear implant (CI) recipients who listen with a hearing aid (HA) in the contralateral ear, known as bimodal listeners, demonstrate individual variability in speech recognition in noise. This variability may be due in part to differences in the processing delays of the CI and HA devices. This study investigated the influence of matching the processing delays of CI and HA devices on masked speech recognition for bimodal listeners.Method: Twelve postlingually deafened adult CI recipients completed a task of masked speech recognition in two listening conditions: (a) independent default CI and HA processing delays (mismatched) and (b) with their HA-specific delay applied to the CI processing delay (matched). Speech recognition was evaluated with AzBio sentences presented in a 10-talker masker at a 0 dB SNR. The target was presented from the front loudspeaker at 0° azimuth, and the masker was co-located with the target, presented 90° toward the CI ear, or presented 90° toward the HA ear.Results: There was a significant main effect for target-to-masker configuration, with better performance when the masker was spatially separated from the target. Better masked speech recognition was observed in the matched condition as compared to the mismatched condition.Conclusion: Bimodal listeners may experience better masked speech recognition when the processing delay of the CI is individualized to match the processing delay of the contralateral HA.Supplemental Material S1. Raw data of speech recognition across masker configurations for the sample, ranked by age at time of test. Listed in percent correct for each condition.Richter, M. E., Rooth, M. A., & Dillon, M. T. (2024). Influence of matching the processing delays of cochlear implant and hearing aid devices for bimodal listeners on speech recognition in noise. American Journal of Audiology, 33(4), 1350–1355. https://doi.org/10.1044/2024_AJA-24-00026

Purpose: Cochlear implant (CI) recipients who listen with a hearing aid (HA) in the contralateral ear, known as bimodal listeners, demonstrate individual variability in speech recognition in noise. This variability may be due in part to differences in the processing delays of the CI and HA devices. This study investigated the influence of matching the processing delays of CI and HA devices on masked speech recognition for bimodal listeners.Method: Twelve postlingually deafened adult CI recipients completed a task of masked speech recognition in two listening conditions: (a) independent default CI and HA processing delays (mismatched) and (b) with their HA-specific delay applied to the CI processing delay (matched). Speech recognition was evaluated with AzBio sentences presented in a 10-talker masker at a 0 dB SNR. The target was presented from the front loudspeaker at 0° azimuth, and the masker was co-located with the target, presented 90° toward the CI ear, or presented 90° toward the HA ear.Results: There was a significant main effect for target-to-masker configuration, with better performance when the masker was spatially separated from the target. Better masked speech recognition was observed in the matched condition as compared to the mismatched condition.Conclusion: Bimodal listeners may experience better masked speech recognition when the processing delay of the CI is individualized to match the processing delay of the contralateral HA.Supplemental Material S1. Raw data of speech recognition across masker configurations for the sample, ranked by age at time of test. Listed in percent correct for each condition.Richter, M. E., Rooth, M. A., & Dillon, M. T. (2024). Influence of matching the processing delays of cochlear implant and hearing aid devices for bimodal listeners on speech recognition in noise. American Journal of Audiology, 33(4), 1350–1355. https://doi.org/10.1044/2024_AJA-24-00026

Purpose: Cochlear implant (CI) recipients with hearing preservation experience significant improvements in speech recognition with electric–acoustic stimulation (EAS) as compared to with a CI alone, although outcomes across EAS users vary. The individual differences in performance may be due in part to default mapping procedures, which result in electric frequency-to-place mismatches for the majority of EAS users. This study assessed the influence of electric mismatches on the early speech recognition for EAS users. Method: Twenty-one participants were randomized at EAS activation to listen exclusively with a default or place-based map. For both groups, the unaided thresholds determined the acoustic cutoff frequency (i.e., > 65 dB HL). For default maps, the electric filter frequencies were assigned to avoid spectral gaps in frequency information but created varying magnitudes of mismatches. For place-based maps, the electric filter frequencies were assigned to avoid frequency-to-place mismatches. Recognition of consonant–nucleus–consonant words and vowels was assessed at activation and 1, 3, and 6 months postactivation. Results: For participants with default maps, electric mismatch at 1500 Hz ranged from 2 to −12.0 semitones (Mdn = −5 semitones). Poorer performance was observed for those with larger magnitudes of electric mismatch. This effect was observed through 6 months of EAS listening experience. Conclusions: The present sample of EAS users experienced better initial performance when electric mismatches were small or eliminated. These data suggest the utility of methods that reduce electric mismatches, such as place-based mapping procedures. Investigation is ongoing to determine whether these differences persist with long-term EAS use. Supplemental Material S1. Descriptive statistics of the vowel recognition and consonant–nucleus–consonant (CNC) word recognition (percent correct) for participants with default maps and participants with place-based maps at each interval. Dillon, M. T., Canfarotta, M. W., Buss, E., Rooth, M. A., Richter, M. E., Overton, A. B., Roth, N. E., Dillon, S. M., Raymond, J. H., Young, A., Pearson, A. C., Davis, A. G., Dedmon, M. M., Brown, K. D., & O'Connell, B. P. (2023). Influence of electric frequency-to-place mismatches on the early speech recognition outcomes for electric–acoustic stimulation users. American Journal of Audiology, 32(1), 251–260. https://doi.org/10.1044/2022_AJA-21-00254

Purpose: Cochlear implant (CI) recipients with hearing preservation experience significant improvements in speech recognition with electric–acoustic stimulation (EAS) as compared to with a CI alone, although outcomes across EAS users vary. The individual differences in performance may be due in part to default mapping procedures, which result in electric frequency-to-place mismatches for the majority of EAS users. This study assessed the influence of electric mismatches on the early speech recognition for EAS users. Method: Twenty-one participants were randomized at EAS activation to listen exclusively with a default or place-based map. For both groups, the unaided thresholds determined the acoustic cutoff frequency (i.e., > 65 dB HL). For default maps, the electric filter frequencies were assigned to avoid spectral gaps in frequency information but created varying magnitudes of mismatches. For place-based maps, the electric filter frequencies were assigned to avoid frequency-to-place mismatches. Recognition of consonant–nucleus–consonant words and vowels was assessed at activation and 1, 3, and 6 months postactivation. Results: For participants with default maps, electric mismatch at 1500 Hz ranged from 2 to −12.0 semitones (Mdn = −5 semitones). Poorer performance was observed for those with larger magnitudes of electric mismatch. This effect was observed through 6 months of EAS listening experience. Conclusions: The present sample of EAS users experienced better initial performance when electric mismatches were small or eliminated. These data suggest the utility of methods that reduce electric mismatches, such as place-based mapping procedures. Investigation is ongoing to determine whether these differences persist with long-term EAS use. Supplemental Material S1. Descriptive statistics of the vowel recognition and consonant–nucleus–consonant (CNC) word recognition (percent correct) for participants with default maps and participants with place-based maps at each interval. Dillon, M. T., Canfarotta, M. W., Buss, E., Rooth, M. A., Richter, M. E., Overton, A. B., Roth, N. E., Dillon, S. M., Raymond, J. H., Young, A., Pearson, A. C., Davis, A. G., Dedmon, M. M., Brown, K. D., & O'Connell, B. P. (2023). Influence of electric frequency-to-place mismatches on the early speech recognition outcomes for electric–acoustic stimulation users. American Journal of Audiology, 32(1), 251–260. https://doi.org/10.1044/2022_AJA-21-00254