Department of Audiology and Speech-Language Pathology, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, Karnataka, 575001, India.
Department of Audiology and Speech-Language Pathology, National Institute of Speech and Hearing, Trivandrum, Kerala, 695017, India.
Eur Arch Otorhinolaryngol. 2023 Jul;280(7):3209-3217. doi: 10.1007/s00405-023-07845-w. Epub 2023 Jan 25.
Inter-aural insertion depth difference (IEDD) in bilateral cochlear implant (BiCI) with continuous interleaved sampling (CIS) processing is known to reduce the recognition of speech in noise and spatial release from masking (SRM). However, the independent channel selection in the 'n-of-m' sound coding strategy might have a different effect on speech recognition and SRM when compared to the effects of IEDD in CIS-based findings. This study aimed to investigate the effect of bilateral 'n-of-m' processing strategy and interaural electrode insertion depth difference on speech recognition in noise and SRM under conditions that simulated bilateral cochlear implant listening.
Five young adults with normal hearing sensitivity participated in the study. The target sentences were spatially filtered to originate from 0° and the masker was spatially filtered at 0°, 15°, 37.5°, and 90° using the Oldenburg head-related transfer function database for behind the ear microphone. A 22-channel sine wave vocoder processing based on 'n-of-m' processing was applied to the spatialized target-masker mixture, in each ear. The perceptual experiment involved a test of speech recognition in noise under one co-located condition (target and masker at 0°) and three spatially separated conditions (target at 0°, masker at 15°, 37.5°, or 90° to the right ear).
The results were analyzed using a three-way repeated measure analysis of variance (ANOVA). The effect of interaural insertion depth difference (F (2,8) = 3.145, p = 0.098, ɳ = 0.007) and spatial separation between target and masker (F (3,12) = 1.239, p = 0.339, ɳ = 0.004) on speech recognition in noise was not significant.
Speech recognition in noise and SRM were not affected by IEDD ≤ 3 mm. Bilateral 'n-of-m' processing resulted in reduced speech recognition in noise and SRM.
双侧人工耳蜗植入（BiCI）中采用连续交错采样（CIS）处理的耳间插入深度差（IEDD）已知会降低噪声中的语音识别和空间掩蔽释放（SRM）。然而，与 CIS 研究结果中的 IEDD 相比，“n-of-m”声音编码策略中的独立通道选择可能对语音识别和 SRM 产生不同的影响。本研究旨在研究双侧“n-of-m”处理策略和耳间电极插入深度差对模拟双侧人工耳蜗听力条件下噪声中的语音识别和 SRM 的影响。
5 名听力正常的年轻人参与了本研究。目标句子被空间滤波，使其源自 0°，掩蔽器被空间滤波，位于 0°、15°、37.5°和 90°，使用奥登堡头部相关传递函数数据库，用于耳后麦克风。每个耳朵应用基于“n-of-m”处理的 22 通道正弦波声码器处理，对空间化的目标-掩蔽器混合物进行处理。感知实验包括在一个共定位条件（目标和掩蔽器在 0°）和三个空间分离条件（目标在 0°，掩蔽器在右耳 15°、37.5°或 90°）下的噪声中的语音识别测试。
使用三因素重复测量方差分析（ANOVA）对结果进行分析。耳间插入深度差的影响（F（2，8）=3.145，p=0.098，ɳ=0.007）和目标与掩蔽器之间的空间分离（F（3，12）=1.239，p=0.339，ɳ=0.004）对噪声中的语音识别没有显著影响。
噪声中的语音识别和 SRM 不受 IEDD≤3mm 的影响。双侧“n-of-m”处理导致噪声中的语音识别和 SRM 降低。
