作为旋律频率范围、谐和性和电极数量的函数的人工耳蜗旋律识别。
Cochlear implant melody recognition as a function of melody frequency range, harmonicity, and number of electrodes.
机构信息
School of Medicine, University of California, Irvine, California 92697, USA.
出版信息
Ear Hear. 2009 Apr;30(2):160-8. doi: 10.1097/AUD.0b013e31819342b9.
OBJECTIVE
The primary goal of the present study was to determine how cochlear implant melody recognition was affected by the frequency range of the melodies, the harmonicity of these melodies, and the number of activated electrodes. The secondary goal was to investigate whether melody recognition and speech recognition were differentially affected by the limitations imposed by cochlear implant processing.
DESIGN
Four experiments were conducted. In the first experiment, 11 cochlear implant users used their clinical processors to recognize melodies of complex harmonic tones with their fundamental frequencies being in the low (104-262 Hz), middle (207-523 Hz), and high (414-1046 Hz) ranges. In the second experiment, melody recognition with pure tones was compared to melody recognition with complex harmonic tones in four subjects. In the third experiment, melody recognition was measured as a function of the number of electrodes in five subjects. In the fourth experiment, vowel and consonant recognition were measured as a function of the number of electrodes in the same five subjects who participated in the third experiment.
RESULTS
Frequency range significantly affected cochlear implant melody recognition, with higher frequency ranges producing better performance. Pure tones produced significantly better performance than complex harmonic tones. Increasing the number of activated electrodes did not affect performance with low- and middle-frequency melodies but produced better performance with high-frequency melodies. Large individual variability was observed for melody recognition, but its source seemed to be different from the source of the large variability observed in speech recognition.
CONCLUSION
Contemporary cochlear implants do not adequately encode either temporal pitch or place pitch cues. Melody recognition and speech recognition require different signal processing strategies in future cochlear implants.
目的
本研究的主要目的是确定人工耳蜗旋律识别受旋律的频率范围、这些旋律的谐和性以及激活电极数量的影响。次要目的是研究旋律识别和语音识别是否受到人工耳蜗处理限制的不同影响。
设计
进行了四项实验。在第一项实验中，11 名人工耳蜗使用者使用他们的临床处理器识别基本频率分别处于低频（104-262 Hz）、中频（207-523 Hz）和高频（414-1046 Hz）范围内的复杂谐波音调的旋律。在第二项实验中，比较了四个受试者中纯音和复音的旋律识别。在第三项实验中，测量了五个受试者中旋律识别与电极数量的关系。在第四项实验中，在参与第三项实验的五个相同的受试者中，测量了元音和辅音识别与电极数量的关系。
结果
频率范围对人工耳蜗旋律识别有显著影响，较高的频率范围产生更好的性能。纯音产生的性能明显优于复音。增加激活电极的数量不会影响低频和中频旋律的性能，但会提高高频旋律的性能。尽管对旋律识别存在较大的个体变异性，但它的来源似乎与语音识别中观察到的大变异来源不同。
结论
现代人工耳蜗不能充分编码音调和位置音高线索。旋律识别和语音识别需要未来人工耳蜗中不同的信号处理策略。
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