Matz Alexandria F, Nie Yingjiu, Wheeler Harley J
Department of Otolaryngology, Eastern Virginia Medical School, Norfolk, VA, United States.
Department of Communication Sciences and Disorders, James Madison University, Harrisonburg, VA, United States.
Front Psychol. 2022 Sep 2;13:927854. doi: 10.3389/fpsyg.2022.927854. eCollection 2022.
Voluntary stream segregation was investigated in cochlear implant (CI) users and normal-hearing (NH) listeners using a segregation-promoting objective approach which evaluated the role of spectral and amplitude-modulation (AM) rate separations on stream segregation and its build-up. Sequences of 9 or 3 pairs of A and B narrowband noise (NBN) bursts were presented which differed in either center frequency of the noise band, the AM-rate, or both. In some sequences (delayed sequences), the last B burst was delayed by 35 ms from their otherwise-steady temporal position. In the other sequences (no-delay sequences), the last B bursts were temporally advanced from 0 to 10 ms. A single interval yes/no procedure was utilized to measure participants' sensitivity ( ) in identifying delayed vs. no-delay sequences. A higher value showed the higher ability to segregate the A and B subsequences. For NH listeners, performance improved with each spectral separation. However, for CI users, performance was only significantly better for the condition with the largest spectral separation. Additionally, performance was significantly poorer for the largest AM-rate separation than for the condition with no AM-rate separation for both groups. The significant effect of sequence duration in both groups indicated that listeners made more improvement with lengthening the duration of stimulus sequences, supporting the build-up effect. The results of this study suggest that CI users are less able than NH listeners to segregate NBN bursts into different auditory streams when they are moderately separated in the spectral domain. Contrary to our hypothesis, our results indicate that AM-rate separation may interfere with the segregation of streams of NBN. Additionally, our results add evidence to the literature that CI users build up stream segregation at a rate comparable to NH listeners, when the inter-stream spectral separations are adequately large.
采用一种促进分离的客观方法，对人工耳蜗（CI）使用者和听力正常（NH）的听众的自愿声流分离进行了研究，该方法评估了频谱和幅度调制（AM）速率分离对声流分离及其形成的作用。呈现了9对或3对A和B窄带噪声（NBN）脉冲序列，它们在噪声带的中心频率、AM速率或两者上有所不同。在一些序列（延迟序列）中，最后一个B脉冲从其原本稳定的时间位置延迟35毫秒。在其他序列（无延迟序列）中，最后一个B脉冲在时间上提前0到10毫秒。采用单间隔是/否程序来测量参与者在识别延迟序列与无延迟序列时的敏感度（）。较高的值表明分离A和B子序列的能力越强。对于NH听众，随着每次频谱分离，表现有所改善。然而，对于CI使用者，只有在频谱分离最大的情况下，表现才显著更好。此外，对于两组而言，最大AM速率分离时的表现明显比无AM速率分离时更差。两组中序列持续时间的显著影响表明，随着刺激序列持续时间的延长，听众有更大的改善，这支持了形成效应。本研究结果表明，当NBN脉冲在频谱域中适度分离时，CI使用者比NH听众更难将其分离成不同的听觉流。与我们的假设相反，我们的结果表明AM速率分离可能会干扰NBN流的分离。此外，我们的结果为文献增添了证据，即当流间频谱分离足够大时，CI使用者形成声流分离的速率与NH听众相当。
