Boëx Colette, de Balthasar Chloé, Kós Maria-Izabel, Pelizzone Marco
Centre Romand d'Implants Cochléaires, University Hospital, CH-1211 Geneva 14, Switzerland.
J Acoust Soc Am. 2003 Oct;114(4 Pt 1):2049-57. doi: 10.1121/1.1610451.
The goal of this study was to evaluate electrical field interactions produced by the stimulation of different types of intracochlear electrodes in 12 adult subjects (three Ineraid, four Clarion S-Series, three S-Series with the electrode positioning system-EPS and two Clarion HiFocus-I with the EPS). Psychophysical measurements were conducted with biphasic stimuli (813 pulse per second, 153.8 micros/phase). "Perturbation" signals (300 ms) were applied to one electrode chosen at the middle of the array and their effects on detection thresholds of "probe" signals (30 ms) were measured on the neighbor basal electrode. Perturbation levels were set below the detection threshold of the perturbation electrode (-2 dB re threshold). Measurements were first conducted for simultaneous stimulation of the probe and of the perturbation electrodes, for monopolar for all subjects and for bipolar stimulus configurations for both Clarion HiFocus-I subjects. The tested Clarion electrodes did not present lower monopolar interactions than the Ineraid electrodes. Nevertheless, considering the shorter distance between electrodes for the Clarion than for the Ineraid, the tested Clarion electrodes might be more selective than the Ineraid. We did not find any significant monopolar electrical field-interaction differences between subjects who received the S-Series array with and without the EPS. We did not find lower interactions for both subjects who received the HiFocus-I array than for subjects who received the S-Series. Electrical field interactions were lower for bipolar than for monopolar configurations for both HiFocus-I subjects. A second set of measurements was conducted for nonsimultaneous stimulation similar to the one used in continuous interleaved sampling sound strategy. These measurements showed that interactions evaluated for simultaneous biphasic stimuli were larger than for nonsimultaneous stimulation.
本研究的目的是评估在12名成年受试者（三名Ineraid、四名Clarion S-Series、三名配备电极定位系统-EPS的S-Series以及两名配备EPS的Clarion HiFocus-I）中，不同类型的耳蜗内电极刺激所产生的电场相互作用。采用双相刺激（每秒813个脉冲，每相153.8微秒）进行心理物理学测量。将“扰动”信号（300毫秒）施加于阵列中部选择的一个电极，并测量其对相邻基底电极上“探测”信号（30毫秒）检测阈值的影响。扰动水平设置在扰动电极检测阈值以下（相对于阈值为-2分贝）。首先针对探测电极和扰动电极的同时刺激进行测量，所有受试者均采用单极刺激，两名Clarion HiFocus-I受试者采用双极刺激配置。测试的Clarion电极在单极相互作用方面并不比Ineraid电极低。然而，考虑到Clarion电极之间的距离比Ineraid电极短，测试的Clarion电极可能比Ineraid电极更具选择性。我们没有发现接受带或不带EPS的S-Series阵列的受试者之间存在任何显著的单极电场相互作用差异。我们没有发现接受HiFocus-I阵列的两名受试者的相互作用比接受S-Series阵列的受试者低。对于两名HiFocus-I受试者，双极配置的电场相互作用低于单极配置。进行了第二组测量，用于非同时刺激，类似于连续交错采样声音策略中使用的刺激。这些测量结果表明，同时双相刺激评估的相互作用大于非同时刺激。
