Jaisinghani Priyanka, Yoon Yang-Soo
Department of Speech and Hearing Sciences, Lamar University, Beaumont, TX.
Department of Communication Sciences and Disorders, Baylor University, Waco, TX.
J Speech Lang Hear Res. 2025 Feb 4;68(2):792-807. doi: 10.1044/2024_JSLHR-24-00273. Epub 2025 Jan 9.
The aim of this study was to measure the effects of frequency spacing (i.e., F2 minus F1) on spectral integration for vowel perception in simulated bilateral electric-acoustic stimulation (BiEAS), electric-acoustic stimulation (EAS), and bimodal hearing.
Twenty listeners with typical hearing participated in synthetic vowel recognition. Four vowels were used with varying frequency spacings (/ͻ/: 270 Hz, /ʊ/: 653 Hz, /æ/: 1040 Hz, and /I/: 1607 Hz). F1 was acoustically simulated with a band-pass filtering, while F2 was electrically simulated using an eight-channel sine wave vocoder with matched input and output frequency range. Vowel recognition was measured in five listening conditions: BiEAS (F1 and F2 in both ears), EAS (F1 and F2 in the left ear), bimodal (F1 and F2 in opposite ears), cochlear implant alone (F2 alone in the left ear), and hearing aid alone (F1 alone in the left ear).
In EAS, spectral integration was significantly better at a 270-Hz spacing, while in bimodal hearing, spectral integration was significantly poorer at a 1607-Hz frequency compared to other frequency spacings. BiEAS conditions offered the best spectral integration, regardless of frequency spacing. Vowel confusion remained consistent and below chance level across the first three listening conditions. Bimodal interference occurred for the /I/ vowel when the cochlear implant ear perceives the dominant cue and the hearing aid ear perceives the nondominant cue. The F2 place cue is transmitted significantly better than the F1 height cue in BiEAS, EAS, and bimodal conditions.
EAS and bimodal hearing integrates narrower frequency ranges better than wider spacings. EAS hearing provided greater outcomes over bimodal hearing, suggesting that within-ear (EAS) integration is more effective than across-ear (bimodal) integration. Bimodal interference may be a factor for variability in bimodal performance. Cautious interpretation and further research with real EAS and bimodal users are suggested to validate and extend these findings.
本研究旨在测量频率间距（即F2减去F1）对模拟双侧电声刺激（BiEAS）、电声刺激（EAS）和双耳模式听力中元音感知的频谱整合的影响。
20名听力正常的受试者参与了合成元音识别测试。使用了四个具有不同频率间距的元音（/ɔ/：270Hz，/ʊ/：653Hz，/æ/：1040Hz，/i/：1607Hz）。F1通过带通滤波进行声学模拟，而F2使用具有匹配输入和输出频率范围的八通道正弦波声码器进行电模拟。在五种听力条件下测量元音识别：BiEAS（双耳中的F1和F2）、EAS（左耳中的F1和F2）、双耳模式（双耳中的F1和F2）、单独使用人工耳蜗（左耳单独的F2）和单独使用助听器（左耳单独的F1）。
在EAS中，270Hz间距时的频谱整合明显更好，而在双耳模式听力中，与其他频率间距相比，1607Hz频率下的频谱整合明显更差。无论频率间距如何，BiEAS条件下的频谱整合最佳。在前三种听力条件下，元音混淆保持一致且低于随机水平。当人工耳蜗耳感知主导线索而助听器耳感知非主导线索时，/i/元音会出现双耳模式干扰。在BiEAS、EAS和双耳模式条件下，F2位置线索的传递明显优于F1高度线索。
EAS和双耳模式听力对较窄频率范围的整合优于较宽的间距。EAS听力比双耳模式听力产生更好的结果，表明耳内（EAS）整合比跨耳（双耳模式）整合更有效。双耳模式干扰可能是双耳模式性能变异性的一个因素。建议谨慎解读，并对实际的EAS和双耳模式使用者进行进一步研究，以验证和扩展这些发现。
