Electrophysiological Spread of Excitation and Pitch Perception for Dual and Single Electrodes Using the Nucleus Freedom Cochlear Implant
Electrophysiological Spread of Excitation and Pitch Perception for Dual and Single Electrodes Using the Nucleus Freedom Cochlear Implant
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DOI：
10.1097/aud.0b013e318181a878
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发表时间：
2008-12-01
期刊：
影响因子：
3.7
通讯作者：
Pesch, Joerg
中科院分区：
文献类型：
--
作者：
Busby, Peter A.;Battmer, Rolf D.;Pesch, Joerg
目的：本研究的第一个目的是确定 Nucleus (R) Freedom (TM) 人工耳蜗系统的双电极和单电极刺激之间的电生理兴奋传播 (SOE) 功能（使用电诱发复合动作电位 (ECAP) 测量）是否存在一致的差异。双电极刺激是通过电耦合两个相邻的单电极产生的。第二个目标是确定 SOE 功能与心理物理学测量的双电极和单电极音高等级之间是否存在任何关系。 设计：九名成人人工耳蜗受试者参与了这项研究。使用前向掩蔽范例测量双电极和单电极刺激的 ECAP，该范例也用于具有 Nucleus 植入的神经响应遥测 (TM) (NRT (TM)) 软件。研究软件用于生成双电极和单电极刺激并记录 ECAP。在阵列上三个位置的双电极和两个相邻的单电极上测量激发扩散 (SOE)：顶端、中部和基底。比较的是 SOE 函数峰值处的 ECAP 振幅、缩放 SOE 函数在 75% 点处的宽度，以及 SOE 函数峰值处以及缩放函数顶端和基部侧 75%、50% 和 25% 点处的电极位置。对相同组的双电极和单电极测量间距等级。使用两种替代的强制选择程序，每组中的电极彼此配对为AB和BA对。受试者指出两种刺激中哪一种的音调较高。结果：使用与测量单电极 SOE 相同的方法可以成功获得双电极 SOE。双电极和单电极 SOE 的形状相似。双电极在 SOE 函数峰值处存在 ECAP 振幅较高的趋势，但这仅对于顶端和基部位置的两次比较才显着。双电极和单电极之间的 SOE 宽度没有显着差异。在大多数情况下，SOE 功能峰值处以及 75% 位置处功能的顶端和基底侧的电极是按音调排序的。在 50% 和 25% 位置，双电极和单电极之间的显着差异较小。音调排序结果显示，在 74% 的情况下，每个位置的单电极和双电极都成功地按照预期的音调顺序进行排序。音调排序结果与 SOE 功能上的电极排序之间不存在统计上显着的相关性。结论：双电极刺激产生与单电极刺激相似的 SOE 功能。发现了 SOE 峰值处和函数侧面的电极音位排序，但这与音调排序结果没有统计相关性。总结：使用 Nucleus (R) Freedom (TM) 人工耳蜗植入对 9 名受试者使用双电极和单电极研究了神经兴奋 (SOE) 和音调感知的电生理传播。双电极是通过电耦合两个相邻的单电极而产生的。双电极和单电极 SOE 的形状相似。通常发现双电极具有较高的电生理响应幅度。双电极和单电极之间的 SOE 宽度没有差异。在四分之三的案例中，双电极和单电极成功地按照预期的音调顺序进行了音调排序。未发现推介排名与 SOE 功能之间存在显着关系。
Objectives: The first objective of the study was to determine whether there were any consistent differences in the electrophysiological spread of excitation (SOE) function, as measured using the electrically evoked compound action potential (ECAP), between dual and single electrode stimulation with the Nucleus (R) Freedom (TM) cochlear implant system. Dual electrode stimulation is produced by electrically coupling two adjacent single electrodes. The second objective was to determine whether there were any relationships between the SOE functions and psychophysically measured pitch ranking of dual and single electrodes.Design: Nine adult cochlear implant subjects participated in the study. ECAPs for dual and single electrode stimulation were measured using the forward masking paradigm, as also used in the Neural Response Telemetry (TM) (NRT (TM)) software with the Nucleus implant. Research software was used to generate the dual and single electrode stimuli and record the ECAPs. Spread of excitations (SOEs) were measured on a dual electrode and the two adjacent single electrodes, at three positions on the array: apical, mid, and basal. Compared were the ECAP amplitudes at the peak of the SOE functions, the widths of the scaled SOE functions at the 75% point, and the electrode positions at the peak of the SOE function and at the 75%, 50%, and 25% points on apical and basal sides of the scaled functions. Pitch ranking was measured for the same sets of dual and single electrodes. A two-alternative forced choice procedure was used, with the electrodes in each set paired with each other as AB and BA pairs. The subject indicated which of the two stimuli had the higher pitch.Results: Dual electrode SOEs could be successfully obtained using the same methods as used to measure single electrode SOEs. The shapes of the dual and single electrodes SOEs were similar. There was a trend of a higher ECAP amplitude for the dual electrode at the peak of the SOE function, but this was only significant for two comparisons at the apical and basal positions. There were no significant differences in the SOE widths between dual and single electrodes. The electrodes at the peak of the SOE function and on the apical and basal sides of the function at the 75% position were, in most cases, tonotopically ordered. At the 50% and 25% positions, there were fewer significant differences between the dual and single electrodes The pitch ranking results showed that in 74% of cases, the single and dual electrodes at each position were successfully ranked in the expected tonotopic order. There were no statistically significant correlations between the pitch ranking results and the ordering of electrodes on the SOE functions.Conclusions: Dual electrode stimulation produced similar SOE functions as single electrode stimulation. A tonotopic ordering of electrodes at the peak of the SOE and on the sides of the functions was found, but this was not statistically related to the pitch ranking results.Summary: Electrophysiological spread of neural excitation (SOE) and pitch perception using dual and single electrodes was investigated in nine subjects using the Nucleus (R) Freedom (TM) cochlear implant. Dual electrodes are produced by electrically coupling two adjacent single electrodes. The dual and single electrodes SOEs were similar in shape. Higher electrophysiological response amplitudes were generally found for the dual electrodes. There were no differences in SOE widths between dual and single electrodes. In three quarters of cases, dual and single electrodes were successfully pitch ranked in the expected tonotopic order. No significant relationships between pitch ranking and the SOE functions were found.