Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
J Acoust Soc Am. 2018 May;143(5):3114. doi: 10.1121/1.5038254.
Forward masking experiments at 4 kHz have demonstrated that preceding sound can elicit changes in masking patterns consistent with a change in cochlear gain. However, the acoustic environment is filled with complex sounds, often dominated by lower frequencies, and ipsilateral cochlear gain reduction at frequencies below 4 kHz is largely unstudied in the forward masking literature. In this experiment, the magnitude of ipsilateral cochlear gain reduction was explored at 1, 2, and 4 kHz using forward masking techniques in an effort to evaluate a range of frequencies in listeners with normal hearing. Gain reduction estimates were not significantly different at 2 and 4 kHz using two forward masking measurements. Although the frequency was a significant factor in the analysis, post hoc testing supported the interpretation that gain reduction estimates measured without a masker were not significantly different at 1, 2, and 4 kHz. A second experiment provided evidence that forward masking in this paradigm at 1 kHz cannot be explained by excitation alone. This study provides evidence of ipsilateral cochlear gain reduction in humans at frequencies below the 4 kHz region.
在 4 kHz 进行的前向掩蔽实验表明，先前的声音可以引起掩蔽模式的变化，这与耳蜗增益的变化一致。然而，在复杂的声学环境中，声音通常以低频为主，而在 4 kHz 以下的同侧耳蜗增益降低在向前掩蔽文献中研究甚少。在这个实验中，使用前向掩蔽技术在 1、2 和 4 kHz 处探索同侧耳蜗增益降低的幅度，以评估正常听力人群的一系列频率。使用两种前向掩蔽测量，在 2 和 4 kHz 处的增益降低估计值没有显著差异。虽然频率是分析中的一个重要因素，但事后测试支持这样的解释，即没有掩蔽器的增益降低估计值在 1、2 和 4 kHz 处没有显著差异。第二项实验提供了证据，证明该范式在 1 kHz 处的前向掩蔽不能仅通过激励来解释。本研究为人类在 4 kHz 以下频率的同侧耳蜗增益降低提供了证据。
