Marimuthu Vijay, Swanson Brett A, Mannell Robert
Department of Linguistics, Macquarie University, Sydney, Australia.
Cochlear Limited, Sydney, Australia
Trends Hear. 2016 Apr 19;20:2331216516643085. doi: 10.1177/2331216516643085.
Six Nucleus cochlear implant recipients participated in a study investigating the effect of place of stimulation on melody perception using rate-pitch cues. Each stimulus was a pulse train delivered on either a single electrode or multiple electrodes sequentially. Four spatial stimulation patterns were used: a single apical electrode, a single mid electrode, a pair of electrodes (apical and mid), and 11 electrodes (from apical to mid). Within one block of trials, all stimuli had the same spatial stimulation pattern, with pulse rate varying from 131 to 262 pps. An additional pulse rate range of 262 to 523 pps was tested with the single-electrode stimuli. Two experimental procedures were used: note ranking; and a modified melodies test with backwards and warp modification. In each trial of the modified melodies test, a familiar melody and a version with modified pitch were presented (in random order), and the subject's task was to select the unmodified melody. There were no significant differences in performance for stimulation on 1, 2, or 11 electrodes, implying that recipients were unable to combine temporal information from different places in the cochlea to give a stronger pitch cue. No advantage of apical electrodes was found: at the lower pulse rates, there were no significant differences between electrodes; and at the higher pulse rates, scores on the apical electrode dropped more than those on the mid electrode.
六名接受人工耳蜗植入的患者参与了一项研究，该研究使用速率-音高线索来探究刺激部位对旋律感知的影响。每个刺激都是在单个电极或多个电极上依次传递的脉冲序列。使用了四种空间刺激模式：单个顶电极、单个中电极、一对电极（顶电极和中电极）以及11个电极（从顶电极到中电极）。在一组试验中，所有刺激具有相同的空间刺激模式，脉冲率在131至262脉冲每秒之间变化。对于单电极刺激，还测试了262至523脉冲每秒的额外脉冲率范围。使用了两种实验程序：音符排序；以及带有反向和扭曲修改的改良旋律测试。在改良旋律测试的每次试验中，呈现一首熟悉的旋律和一个音高修改后的版本（顺序随机），受试者的任务是选择未修改的旋律。在1个、2个或11个电极上进行刺激时，表现没有显著差异，这意味着受试者无法将来自耳蜗不同部位的时间信息结合起来以给出更强的音高线索。未发现顶电极有优势：在较低脉冲率下，电极之间没有显著差异；在较高脉冲率下，顶电极上的得分下降幅度比中电极上的更大。
