Temporal representations with cochlear implants.
Temporal representations with cochlear implants.
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发表时间：
1997-11
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通讯作者：
Blake S. Wilson;C. C. Finley-C.;D. T. Lawson;M. Zerbi
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作者：
Blake S. Wilson;C. C. Finley-C.;D. T. Lawson;M. Zerbi
目的记录和表征人工耳蜗植入患者各种电刺激的耳蜗内诱发电位（EPs）。方法对直接经皮接触植入电极的患者进行记录。通过非刺激电极记录耳蜗内电压。刺激包括脉冲速率从100到4065/s的相同脉冲序列，以及由单通道语音处理器产生的调制脉冲序列，脉冲速率为824/s。结果当脉冲速率低于200/s时，相同脉冲序列中每个脉冲的EPs值是均匀的。当脉冲速率在400 ~ 1000/s之间时，观察到脉冲电位的交替模式，即奇数脉冲后的脉冲电位相对较大。当速率在1000到3000/s之间时，观察到更复杂的模式。在以更高的频率进行每组训练的第一毫秒后，再次观察到均匀的脉冲电位，尽管脉冲电位的绝对值远低于低频率刺激时观察到的值。这些不同区域之间的边界对应的近似速率在受试者之间和受试者内部的电极之间是不同的。调制脉冲序列的电位值反映了调制波形的总体周期性，但不反映周期内的时间细节。结论：听觉神经的群体反应反映了脉冲速率低于200/s和高于3000/s时的电脉冲幅度。使用中间速率可能会导致人工耳蜗刺激信息传输失真。
OBJECTIVE To record and characterize intracochlear evoked potentials (EPs) for a variety of electrical stimuli in studies with cochlear implant patients. METHODS Recordings were made with patients having direct percutaneous access to their implanted electrodes. Intracochlear voltages were recorded via unstimulated electrodes. The stimuli included trains of identical pulses, with pulse rates ranging from 100 to 4065/s, and a modulated pulse train produced by a single-channel speech processor, with the pulse rate of 824/s. RESULTS Magnitudes of EPs for each pulse in trains of identical pulses were uniform for pulse rates below about 200/s. For rates between about 400 and 1000/s, an alternating pattern of EP magnitudes was observed, with relatively large EPs following the odd-numbered pulses. For rates between about 1000 and 3000/s, more complex patterns were observed. After the first millisecond of each train at even higher rates, uniform EPs again were observed across pulses, although the absolute magnitude of the EPs was much lower than that observed for low rates of stimulation. The approximate rates corresponding to boundaries between these different regions varied among subjects and among electrodes within subjects. EP magnitudes for the modulated pulse train reflected the gross periodicity of the modulation waveform but did not reflect temporal details within the periods. CONCLUSIONS Population responses of the human auditory nerve, as indicated by EP magnitudes, reflect the amplitudes of electrical pulses for pulse rates below about 200/s and above about 3000/s. Use of intermediate rates may introduce distortions in the transmission of stimulus information with cochlear implants.