Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, 1215 21st Avenue South, Nashville, Tennessee 37232, USA.
Department of Electrical Engineering & Computer Science, Vanderbilt University, 2201 West End Avenue, Nashville, Tennessee 37235, USA.
J Acoust Soc Am. 2019 Mar;145(3):1556. doi: 10.1121/1.5092350.
This study investigated the number of channels needed for maximum speech understanding and sound quality in 30 adult cochlear implant (CI) recipients with perimodiolar electrode arrays verified via imaging to be completely within scala tympani (ST). Performance was assessed using a continuous interleaved sampling (CIS) strategy with 4, 8, 10, and 16 channels and n-of-m with 16 maxima. Listeners were administered auditory tasks of speech understanding [monosyllables, sentences (quiet and +5 dB signal-to-noise ratio, SNR), vowels, consonants], spectral modulation detection, as well as subjective estimates of sound quality. Results were as follows: (1) significant performance gains were observed for speech in quiet (monosyllables and sentences) with 16- as compared to 8-channel CIS, (2) 16 channels in a 16-of-m strategy yielded significantly higher outcomes than 16-channel CIS for sentences in noise (percent correct and subjective sound quality) and spectral modulation detection, (3) 16 channels in a 16-of-m strategy yielded significantly higher outcomes as compared to 8- and 10-channel CIS for monosyllables, sentences (quiet and noise), consonants, spectral modulation detection, and subjective sound quality, (4) 16 versus 8 maxima yielded significantly higher speech recognition for monosyllables and sentences in noise using an n-of-m strategy, and (5) the degree of benefit afforded by 16 versus 8 maxima was inversely correlated with mean electrode-to-modiolus distance. These data demonstrate greater channel independence with perimodiolar electrode arrays as compared to previous studies with straight electrodes and warrant further investigation of the minimum number of maxima and number of channels needed for maximum auditory outcomes.
本研究调查了 30 名使用经成像验证完全位于鼓阶（scala tympani，ST）内的植入式电极的成年人工耳蜗（cochlear implant，CI）受者实现最大言语理解和音质所需的通道数量。使用连续交错采样（continuous interleaved sampling，CIS）策略（4、8、10 和 16 个通道）和 n-of-m（16 个最大值）评估了性能。通过言语理解测试（单音节、句子（安静和+5 dB 信噪比，signal-to-noise ratio，SNR）、元音、辅音）、频谱调制检测以及音质的主观评估来评估听力表现。结果如下：（1）16 通道 CIS 较 8 通道 CIS 显著提高了安静状态下（单音节和句子）的言语理解能力；（2）16-of-m 策略中的 16 个通道在噪声下（句子的正确百分比和主观音质）和频谱调制检测中显著提高了结果，优于 16 通道 CIS；（3）与 8 通道和 10 通道 CIS 相比，16-of-m 策略中的 16 个通道在单音节、句子（安静和噪声）、辅音、频谱调制检测和音质主观评估中显著提高了结果；（4）与 8 个最大值相比，n-of-m 策略显著提高了单音节和句子在噪声中的言语识别，而 16 个最大值显著提高了结果；（5）与使用直电极的先前研究相比，使用植入式电极的通道独立性更高，16 个最大值与 8 个最大值相比提供的优势程度与电极到调制器的平均距离成反比。这些数据表明，与先前使用直电极的研究相比，使用植入式电极具有更大的通道独立性，需要进一步研究获得最大听觉效果所需的最小最大值数量和通道数量。
