Polarity effects on place pitch and loudness for three cochlear-implant designs and at different cochlear sites
Polarity effects on place pitch and loudness for three cochlear-implant designs and at different cochlear sites
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DOI：
10.1121/1.4807900
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发表时间：
2013-07-01
影响因子：
2.4
通讯作者：
Macherey, Olivier
中科院分区：
文献类型：
--
作者：
Carlyon, Robert P.;Deeks, John M.;Macherey, Olivier
Advanced Bionics， MedEl和Cochlear公司植入物的用户平衡了单极模式下呈现的极性相反的不对称脉冲序列的响度。对于高级仿生学和MedEl用户来说，脉冲是三相的，包括一个32亩的中心相位，两侧是两个32亩的相反极性和一半振幅的相位。中心相为阳极相（TP-A）或阴极相（TP-C）。对于人工耳蜗公司的用户来说，脉冲由两个32亩的相同极性的相位组成，间隔为8亩的间隙，两侧是两个32亩极性相反的相位，每个相位与中心部分间隔为58亩的间隙。这些四相脉冲的中心部分为阳极（QP-A）或阴极（QP-C），并且所有相位具有相同的振幅。达到匹配响度所需的电流在阳极刺激下比在阴极刺激下要低。这种极性效应在研究的所有电极位置都是相似的，包括MedEl装置的最顶端电极，它刺激耳蜗的最顶端。此外，当四相脉冲以双极模式呈现时，听者报告说，当中心部分在更顶端的电极上呈阳极时，听到的音调比在更底部的电极上听到的音调低。该结果重复了先前的报告，即与大多数动物研究的结果不同，人类人工耳蜗听者对阳极电流比阴极电流更敏感，并将这些发现扩展到更广泛的耳蜗部位，植入物类型和脉冲形状。(C) 2013年美国声学学会。
Users of Advanced Bionics, MedEl, and Cochlear Corp. implants balanced the loudness of trains of asymmetric pulses of opposite polarities presented in monopolar mode. For the Advanced Bionics and MedEl users the pulses were triphasic and consisted of a 32-mu s central phase flanked by two 32-mu s phases of opposite polarity and half the amplitude. The central phase was either anodic (TP-A) or cathodic (TP-C). For the Cochlear Corp. users, pulses consisted of two 32-mu s phases of the same polarity separated by an 8-mu s gap, flanked by two 32-mu s phases of the opposite polarity, each of which was separated from the central portion by a 58-mu s gap. The central portion of these quadraphasic pulses was either anodic (QP-A) or cathodic (QP-C), and all phases had the same amplitude. The current needed to achieve matched loudness was lower for the anodic than for the cathodic stimuli. This polarity effect was similar across all electrode locations studied, including the most apical electrode of the MedEl device which stimulates the very apex of the cochlea. In addition, when quadraphasic pulses were presented in bipolar mode, listeners reported hearing a lower pitch when the central portion was anodic at the more apical, than at the more basal, electrode. The results replicate previous reports that, unlike the results of most animal studies, human cochlear implant listeners are more sensitive to anodic than to cathodic currents, and extend those findings to a wider range of cochlear sites, implant types, and pulse shapes. (C) 2013 Acoustical Society of America.