Ehlers Erica, Goupell Matthew J, Zheng Yi, Godar Shelly P, Litovsky Ruth Y
University of Wisconsin-Madison, Waisman Center, 1500 Highland Avenue, Madison, Wisconsin 53705, USA.
Department of Hearing and Speech Sciences, University of Maryland, College Park, Maryland 20742, USA.
J Acoust Soc Am. 2017 Jun;141(6):4264. doi: 10.1121/1.4983824.
Children who are deaf and receive bilateral cochlear implants (BiCIs) perform better on spatial hearing tasks using bilateral rather than unilateral inputs; however, they underperform relative to normal-hearing (NH) peers. This gap in performance is multi-factorial, including the inability of speech processors to reliably deliver binaural cues. Although much is known regarding binaural sensitivity of adults with BiCIs, less is known about how the development of binaural sensitivity in children with BiCIs compared to NH children. Sixteen children (ages 9-17 years) were tested using synchronized research processors. Interaural time differences and interaural level differences (ITDs and ILDs, respectively) were presented to pairs of pitch-matched electrodes. Stimuli were 300-ms, 100-pulses-per-second, constant-amplitude pulse trains. In the first and second experiments, discrimination of interaural cues (either ITDs or ILDs) was measured using a two-interval left/right task. In the third experiment, subjects reported the perceived intracranial position of ITDs and ILDs in a lateralization task. All children demonstrated sensitivity to ILDs, possibly due to monaural level cues. Children who were born deaf had weak or absent sensitivity to ITDs; in contrast, ITD sensitivity was noted in children with previous exposure to acoustic hearing. Therefore, factors such as auditory deprivation, in particular, lack of early exposure to consistent timing differences between the ears, may delay the maturation of binaural circuits and cause insensitivity to binaural differences.
接受双侧人工耳蜗植入（BiCIs）的聋儿在使用双侧而非单侧输入进行空间听力任务时表现更好；然而，他们相对于听力正常（NH）的同龄人表现较差。这种表现差距是多因素的，包括语音处理器无法可靠地传递双耳线索。尽管对于接受BiCIs的成年人的双耳敏感性已经有很多了解，但与NH儿童相比，接受BiCIs的儿童双耳敏感性的发展情况却知之甚少。16名儿童（9至17岁）使用同步研究处理器进行了测试。将双耳时间差和双耳声级差（分别为ITD和ILD）呈现给一对音高匹配的电极。刺激为300毫秒、每秒100个脉冲、恒定幅度的脉冲序列。在第一个和第二个实验中，使用双间隔左右任务测量对双耳线索（ITD或ILD）的辨别能力。在第三个实验中，受试者在定位任务中报告ITD和ILD的颅内感知位置。所有儿童都表现出对ILD的敏感性，这可能是由于单耳声级线索。先天性聋儿对ITD的敏感性较弱或不存在；相比之下，之前有过听觉经历的儿童则表现出ITD敏感性。因此，诸如听觉剥夺等因素，特别是缺乏早期接触双耳之间一致的时间差，可能会延迟双耳回路的成熟并导致对双耳差异不敏感。
