Pfingst B E, Holloway L A, Razzaque S A
Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan Medical Center, Ann Arbor 48109-0506, USA.
Hear Res. 1996 Sep 1;98(1-2):77-92. doi: 10.1016/0378-5955(96)00071-8.
Effects of pulse separation on detection of electrical stimulation of the cochlea were studied in 12 profoundly deaf human subjects with Nucleus 22 cochlear implants. Biphasic symmetric pulses were used. Pulse separation is the time from offset of one biphasic pulse to the onset of the next biphasic pulse in the train. Effects of pulse separation were studied in the context of different covariables in four stages of the experiment. Effects of pulse separation seen in the different stages were similar, despite the different covariables. Both pulse separation and the total number of pulses per stimulus seem to be important variables affecting stimulus detection. For 0.5 ms/phase pulses, thresholds were lowest at the shortest pulse separations tested (0.2-1.1 ms) and increased as a function of pulse separation. For 2 ms/phase pulses, detection thresholds were lowest at pulse separations around 7.5 ms, in most cases, and higher at both longer and shorter pulse separations. These results suggest that interactions among adjacent pulses can either hinder or facilitate detection of the signal depending on the magnitudes of pulse separation and phase duration. Pulse separations at which thresholds measured for 2 ms/phase pulses were minimum were fairly consistent across subjects and did not correlate well with speech recognition scores. However, significant variation in this measure across species has been seen.
在12名使用Nucleus 22型人工耳蜗的极重度聋人受试者中，研究了脉冲间隔对耳蜗电刺激检测的影响。采用双相对称脉冲。脉冲间隔是指一串双相脉冲中，一个双相脉冲的结束到下一个双相脉冲开始之间的时间。在实验的四个阶段中，在不同协变量的背景下研究了脉冲间隔的影响。尽管协变量不同，但在不同阶段观察到的脉冲间隔的影响是相似的。脉冲间隔和每个刺激的脉冲总数似乎都是影响刺激检测的重要变量。对于0.5毫秒/相位的脉冲，在测试的最短脉冲间隔（0.2 - 1.1毫秒）时阈值最低，并随着脉冲间隔的增加而升高。对于2毫秒/相位的脉冲，在大多数情况下，检测阈值在7.5毫秒左右的脉冲间隔时最低，在更长和更短的脉冲间隔时更高。这些结果表明，相邻脉冲之间的相互作用可以根据脉冲间隔和相位持续时间的大小，要么阻碍要么促进信号的检测。对于2毫秒/相位脉冲测量的阈值最低时的脉冲间隔在受试者之间相当一致，并且与言语识别分数没有很好的相关性。然而，在不同物种之间已经观察到这一指标的显著差异。
