Medical University of Vienna, Department of Otolaryngology, Head and Neck Surgery, Vienna, Austria.
Medical University of Vienna, Center for Medical Statistics, Informatics, and Intelligent Systems, Vienna, Austria.
Hear Res. 2020 Jul;392:107970. doi: 10.1016/j.heares.2020.107970. Epub 2020 Apr 9.
Recent sound coding strategies for cochlear implants (CI) have focused on the transmission of temporal fine structure to the CI recipient. To date, knowledge about the effects of fine structure coding in electrical hearing is poorly charactarized. The aim of this study was to examine whether the presence of temporal fine structure coding affects how the CI recipient perceives sound. This was done by comparing two sound coding strategies with different temporal fine structure coverage in a longitudinal cross-over setting. The more recent FS4 coding strategy provides fine structure coding on typically four apical stimulation channels compared to FSP with usually one or two fine structure channels. 34 adult CI patients with a minimum CI experience of one year were included. All subjects were fitted according to clinical routine and used both coding strategies for three months in a randomized sequence. Formant frequency discrimination thresholds (FFDT) were measured to assess the ability to resolve timbre information. Further outcome measures included a monosyllables test in quiet and the speech reception threshold of an adaptive matrix sentence test in noise (Oldenburger sentence test). In addition, the subjective sound quality was assessed using visual analogue scales and a sound quality questionnaire after each three months period. The extended fine structure range of FS4 yields FFDT similar to FSP for formants occurring in the frequency range only covered by FS4. There is a significant interaction (p = 0.048) between the extent of fine structure coverage in FSP and the improvement in FFDT in favour of FS4 for these stimuli. FS4 Speech perception in noise and quiet was similar with both coding strategies. Sound quality was rated heterogeneously showing that both strategies represent valuable options for CI fitting to allow for best possible individual optimization.
最近的人工耳蜗（CI）声音编码策略主要集中在向 CI 受者传输时间精细结构上。迄今为止，对电听觉中精细结构编码效果的了解还很差。本研究旨在探讨精细结构编码的存在是否会影响 CI 受者对声音的感知。这是通过在纵向交叉设置中比较两种具有不同时间精细结构覆盖的声音编码策略来实现的。较新的 FS4 编码策略在通常四个刺激通道上提供精细结构编码，而 FSP 通常只有一个或两个精细结构通道。本研究纳入了 34 名具有至少一年 CI 经验的成年 CI 患者。所有受试者均按照临床常规进行适配，并在随机顺序下使用两种编码策略进行三个月的研究。通过测量共振峰频率辨别阈值（FFDT）来评估解析音色信息的能力。进一步的结果测量包括安静时的单音节测试和噪声中的自适应矩阵句子测试（Oldenburger 句子测试）的言语接受阈。此外，在每个三个月的研究结束后，使用视觉模拟量表和声音质量问卷评估主观声音质量。FS4 的扩展精细结构范围产生的 FFDT 与 FSP 相似，对于仅由 FS4 覆盖的频率范围内出现的共振峰。在 FSP 中的精细结构覆盖范围与 FS4 有利于这些刺激的 FFDT 改善之间存在显著的交互作用（p=0.048）。FS4 在噪声和安静中的言语感知与两种编码策略相似。声音质量的评分不均匀，表明两种策略都是 CI 适配的有价值的选择，以实现最佳的个性化优化。
