Adaptation by normal listeners to upward spectral shifts of speech: Implications for cochlear implants
Adaptation by normal listeners to upward spectral shifts of speech: Implications for cochlear implants
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DOI：
10.1121/1.428215
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发表时间：
1999-12-01
影响因子：
2.4
通讯作者：
Wilkinson, L
中科院分区：
文献类型：
--
作者：
Rosen, S;Faulkner, A;Wilkinson, L
多通道人工耳蜗通常会将光谱信息呈现到听觉神经阵列中的错误“位置”，因为电极只能部分插入耳蜗。尽管已知这种频谱偏移会导致模拟中的性能立即大幅下降，但听众能够适应这种偏移的程度还有待研究。此处，模拟了四通道植入对正常听众的影响，并使用未移位的频谱信息和相当于基底膜上 6.5 毫米的基底向移位（1.3-2.9 倍频程，取决于频率）测试了性能。正如预期的那样，未平移的模拟导致了相对较高水平的平均性能（例如，正确识别了句子中 64% 的单词），而平移的模拟导致了非常差的结果（例如，1% 的单词）。然而，经过仅仅 9 次时长 20 分钟的连接对话跟踪和转移模拟，识别音间辅音、单音节中的中间元音和句子中的单词（单词的 30%）的性能显着提高。此外，听众无需唇读就能以每分钟 40 个单词的速度跟踪转换信号的关联对话。尽管我们不知道是否可以完全适应偏移信号，但很明显，短期实验严重夸大了这种频谱偏移的长期后果。 (C) 1999 年美国声学学会。 [S0001-4966(99)02012-3]。
Multi-channel cochlear implants typically present spectral information to the wrong ''place'' in the auditory nerve array, because electrodes can only be inserted partway into the cochlea. Although such spectral shifts are known to cause large immediate decrements in performance in simulations, the extent to which listeners can adapt to such shifts has yet to be investigated. Here, the effects of a four-channel implant in normal listeners have been simulated, and performance tested with unshifted spectral information and with the equivalent of a 6.5-mm basalward shift on the basilar membrane (1.3-2.9 octaves, depending on frequency). As expected, the unshifted simulation led to relatively high levels of mean performance (e;g., 64% of words in sentences correctly identified) whereas the shifted simulation led to very poor results (e.g., 1% of words). However, after just nine 20-min sessions of connected discourse tracking with the shifted simulation, performance improved significantly for the identification of intervocalic consonants, medial vowels in monosyllables, and words in sentences (30% of words). Also, listeners were able to track connected discourse of shifted signals without lipreading at rates up to 40 words per minute. Although we do not know if complete adaptation to the shifted signals is possible, it is clear that short-term experiments seriously exaggerate the long-term consequences of such spectral shifts. (C) 1999 Acoustical Society of America. [S0001-4966(99)02012-3].