van de Velde Daan J, Dritsakis Giorgos, Frijns Johan H M, van Heuven Vincent J, Schiller Niels O
Cochlear Implants Int. 2015 Mar;16(2):77-87. doi: 10.1179/1754762814Y.0000000086. Epub 2014 Jul 7.
Performance of cochlear implant (CI) users on linguistic intonation recognition is poorer than that of normal-hearing listeners, due to the limited spectral detail provided by the implant. A higher spectral resolution is provided by narrow rather than by broad filter slopes. The corresponding effect of the filter slope on the identification of linguistic intonation conveyed by pitch movements alone was tested using vocoder simulations.
Re-synthesized intonation variants of naturally produced phrases were processed by a 15-channel noise vocoder using a narrow (40 dB/octave) and a broad (20 dB/octave) filter slope. There were three different intonation patterns (rise/fall/rise-fall), differentiated purely by pitch and each associated to a different meaning. In both slope conditions as well as a condition with unprocessed stimuli, 24 normally hearing Dutch adults listened to a phrase, indicating which of two meanings was associated to it (i.e. a counterbalanced selection of two of the three contours).
As expected, performance for the unprocessed stimuli was better than for the vocoded stimuli. No overall difference between the filter conditions was found.
These results are taken to indicate that neither the narrow (20 dB/octave) nor the shallow (40 dB/octave) slope provide enough spectral detail to identify pure F(0) intonation contours. For users of a certain class of CIs, results could imply that their intonation perception would not benefit from steeper slopes. For them, perception of pitch movements in language requires more extreme filter slopes, more electrodes, and/or additional (phonetic/contextual) cues.
由于人工耳蜗（CI）提供的频谱细节有限，CI使用者在语言语调识别方面的表现不如正常听力的听众。窄滤波器斜率比宽滤波器斜率能提供更高的频谱分辨率。使用声码器模拟测试了滤波器斜率对仅由音高变化传达的语言语调识别的相应影响。
使用15通道噪声声码器，分别采用窄（40 dB/倍频程）和宽（20 dB/倍频程）滤波器斜率，对自然产生的短语的重新合成语调变体进行处理。有三种不同的语调模式（升调/降调/升降调），仅通过音高区分，每种模式对应不同的含义。在两种斜率条件以及未处理刺激的条件下，24名听力正常的荷兰成年人听一个短语，指出与之相关的两种含义中的哪一种（即从三种轮廓中的两种进行平衡选择）。
正如预期的那样，未处理刺激的表现优于声码转换后的刺激。未发现滤波器条件之间的总体差异（无显著差异）。
这些结果表明，无论是窄（20 dB/倍频程）还是浅（40 dB/倍频程）的斜率，都没有提供足够的频谱细节来识别纯F(0)语调轮廓。对于某类CI使用者来说，结果可能意味着他们的语调感知不会从更陡的斜率中受益。对他们而言，语言中音高变化的感知需要更极端的滤波器斜率、更多的电极和/或额外的（语音/语境）线索。 （备注：文中“no overall difference between the filter conditions was found”直译为“未发现滤波器条件之间的总体差异”，这里补充“无显著差异”使表达更符合中文习惯且表意完整）
