Department of Hearing and Speech Sciences, Cochlear Implants and Psychophysics Laboratory, University of Maryland, College Park, Maryland 20742, USA.
J Acoust Soc Am. 2010 Jan;127(1):415-26. doi: 10.1121/1.3257591.
The objective of this study was to examine the relation between measures of spectral and temporal resolutions in cochlear implant listeners at a particular electrode location. The hypothesis was that a common underlying factor, such as the health of local groups of neurons, might partially determine patients' sensitivity to both spectral and temporal cues at specific tonotopic locations. Participants were adult cochlear implant listeners. A significant correlation was found between electrode discrimination measured at soft levels (20% and 30% of the dynamic range) and modulation sensitivity at those levels, for stimulation in bipolar mode and a 100 Hz modulation rate. Correlations between the two measures were weaker under monopolar stimulation, or when the modulation rate was 10 Hz. At a higher stimulation level (40% of the dynamic range), no significant correlations between these measures were observed. It is hypothesized that the more restricted excitation pattern at lower levels and/or with a narrower stimulation mode allows the measurement of locally driven sensitivity to spectral and temporal cues, particularly under more challenging listening conditions. Thus, psychophysical measures obtained under conditions that evoke a narrower excitation pattern may serve as a useful indicator of the functional health of local neural populations.
本研究旨在探讨特定电极位置处人工耳蜗植入者的光谱和时间分辨率测量值之间的关系。假设一种共同的潜在因素，如局部神经元群的健康状况，可能部分决定患者在特定音调位置对光谱和时间线索的敏感性。参与者为成年人工耳蜗植入者。研究发现，在双极模式和 100Hz 调制率刺激下，在软水平（动态范围的 20%和 30%）测量的电极辨别力与这些水平的调制灵敏度之间存在显著相关性。在单极刺激下或调制率为 10Hz 时，这两个测量值之间的相关性较弱。在更高的刺激水平（动态范围的 40%）下，这两个测量值之间没有观察到显著相关性。研究假设，在较低水平和/或使用较窄的刺激模式下，受激范围更有限，这允许测量局部驱动的对光谱和时间线索的敏感性，尤其是在更具挑战性的听力条件下。因此，在激发模式较窄的条件下获得的心理物理测量值可以作为局部神经群功能健康的有用指标。
