Speech, Hearing and Phonetic Sciences, Division of Psychology and Language Sciences, UCL, Chandler House, 2 Wakefield Street, London WC1N 1PF, United Kingdom.
J Acoust Soc Am. 2010 Mar;127(3):1645-60. doi: 10.1121/1.3293002.
Simulations of monaural cochlear implants in normal hearing listeners have shown that the deleterious effects of upward spectral shifting on speech perception can be overcome with training. This study simulates bilateral stimulation with a unilateral spectral shift to investigate whether listeners can adapt to upward-shifted speech information presented together with contralateral unshifted information. A six-channel, dichotic, interleaved sine-carrier vocoder simulated a binaurally mismatched frequency-to-place map. Odd channels were presented to one ear with an upward frequency shift equivalent to 6 mm on the basilar membrane, while even channels were presented to the contralateral ear unshifted. In Experiment 1, listeners were trained for 5.3 h with either the binaurally mismatched processor or with just the shifted monaural bands. In Experiment 2, the duration of training was 10 h, and the trained condition alternated between those of Experiment 1. While listeners showed learning in both experiments, intelligibility with the binaurally mismatched processor never exceeded, intelligibility with just the three unshifted bands, suggesting that listeners did not benefit from combining the mismatched maps, even though there was clear scope to do so. Frequency-place map alignment may thus be of importance when optimizing bilateral devices of the type studied here.
对正常听力听众的单耳人工耳蜗的模拟研究表明，通过训练可以克服频谱上移对言语感知的有害影响。本研究通过单侧频谱移位模拟双侧刺激，以调查听众是否可以适应与对侧未移位信息一起呈现的上移言语信息。一个六通道、双相、交错正弦载波声码器模拟了一个双侧不匹配的频率-位置图。奇数通道以基底膜上相当于 6 毫米的向上频率移位呈现给一只耳朵，而偶数通道则以未移位的方式呈现给对侧耳朵。在实验 1 中，听众分别接受了 5.3 小时的双耳不匹配处理器或仅移位的单耳带训练。在实验 2 中，训练持续时间为 10 小时，训练条件在实验 1 的条件之间交替。虽然听众在两个实验中都表现出了学习，但双耳不匹配处理器的可懂度从未超过仅使用三个未移位频段的可懂度，这表明听众即使有明显的机会也没有从组合不匹配的图谱中受益。因此，当优化这里研究的双侧设备时，频率-位置图对齐可能很重要。
