1 Research and Technology Labs, Cochlear Ltd., Centennial, CO, USA.
2 Department of Speech-Language-Hearing Sciences, University of Minnesota, Minneapolis, MN, USA.
Trends Hear. 2019 Jan-Dec;23:2331216519831492. doi: 10.1177/2331216519831492.
This study looked at different methods to preserve interaural level difference (ILD) cues for bilateral cochlear implant (BiCI) recipients. One possible distortion to ILD is from automatic gain control (AGC). Localization accuracy of BiCI recipients using default versus increased AGC threshold and linked AGCs versus independent AGCs was examined. In addition, speech reception in noise was assessed using linked versus independent AGCs and enabling and disabling Autosensitivity™ Control. Subjective information via a diary and questionnaire was also collected about maps with linked and independent AGCs during a take-home experience. Localization accuracy improved in the increased AGC threshold and the linked AGCs conditions. Increasing the AGC threshold resulted in a 4° improvement in root mean square error averaged across all speaker locations. Using linked AGCs, BiCI participants experienced an 8° improvement for all speaker locations and a 19° improvement at the speaker location most affected by the AGC. Speech reception threshold in noise improved by an average of 2.5 dB when using linked AGCs versus independent AGCs. In addition, the effect of linked AGCs on speech in noise was compared with that of Autosensitivity™ Control. The Speech, Spatial, and Qualities of Hearing Scale-12 question comparative survey showed an improvement when using maps with linked AGCs. These findings support the hypothesis that ILD cues may be preserved by increasing the AGC threshold or linking AGCs.
本研究着眼于不同的方法来保留双侧人工耳蜗（BiCI）受者的耳间水平差（ILD）线索。自动增益控制（AGC）可能会对 ILD 造成失真。检查了 BiCI 受者在默认 AGC 阈值与增加 AGC 阈值、链接 AGC 与独立 AGC 下的定位准确性。此外，还使用链接 AGC 与独立 AGC 以及启用和禁用 Autosensitivity™ Control 评估了噪声中的言语接受能力。还通过日记和问卷收集了关于在家庭体验期间具有链接和独立 AGC 的映射的主观信息。在增加 AGC 阈值和链接 AGC 条件下，定位准确性得到提高。增加 AGC 阈值使所有说话人位置的均方根误差平均提高了 4°。使用链接 AGC，BiCI 参与者在所有说话人位置的体验提高了 8°，在受 AGC 影响最大的说话人位置提高了 19°。与独立 AGC 相比，使用链接 AGC 时噪声中的言语接受阈值平均提高了 2.5dB。此外，还比较了链接 AGC 对噪声中言语的影响与 Autosensitivity™ Control 的影响。使用具有链接 AGC 的映射时，12 项语音、空间和听觉质量问卷比较调查显示出改善。这些发现支持这样的假设，即通过增加 AGC 阈值或链接 AGC 可以保留 ILD 线索。
