Ausili Sebastian A, Snapp Hillary A
Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 Nijmegen, The Netherlands.
Department of Otolaryngology, University of Miami, 1120 NW 14th Street, 5th Floor, Miami, FL 33136, USA.
Audiol Res. 2023 Aug 3;13(4):586-599. doi: 10.3390/audiolres13040051.
In the absence of binaural hearing, individuals with single-sided deafness can adapt to use monaural level and spectral cues to improve their spatial hearing abilities. Contralateral routing of signal is the most common form of rehabilitation for individuals with single-sided deafness. However, little is known about how these devices affect monaural localization cues, which single-sided deafness listeners may become reliant on. This study aimed to investigate the effects of contralateral routing of signal hearing aids on localization performance in azimuth and elevation under monaural listening conditions.
Localization was assessed in 10 normal hearing adults under three listening conditions: (1) normal hearing (NH), (2) unilateral plug (NH-plug), and (3) unilateral plug and CROS aided (NH-plug + CROS). Monaural hearing simulation was achieved by plugging the ear with E-A-Rsoft™ FX™ foam earplugs. Stimuli consisted of 150 ms high-pass noise bursts (3-20 kHz), presented in a random order from fifty locations spanning ±70° in the horizontal and ±30° in the vertical plane at 45, 55, and 65 dBA.
In the unilateral plugged listening condition, participants demonstrated good localization in elevation and a response bias in azimuth for signals directed at the open ear. A significant decrease in performance in elevation occurs with the contralateral routing of signal hearing device on, evidenced by significant reductions in response gain and low value. Additionally, performance in azimuth is further reduced for contralateral routing of signal aided localization compared to the simulated unilateral hearing loss condition. Use of the contralateral routing of signal device also results in a reduction in promptness of the listener response and an increase in response variability.
Results suggest contralateral routing of signal hearing aids disrupt monaural spectral and level cues, which leads to detriments in localization performance in both the horizontal and vertical dimensions. Increased reaction time and increasing variability in responses suggests localization is more effortful when wearing the contralateral rerouting of signal device.
在双耳听力缺失的情况下，单侧耳聋患者可通过适应使用单耳的响度和频谱线索来提高其空间听觉能力。信号对侧路由是单侧耳聋患者最常见的康复形式。然而，对于这些设备如何影响单耳定位线索，以及单侧耳聋的听众可能会如何依赖这些线索，我们知之甚少。本研究旨在探讨信号对侧路由助听器在单耳聆听条件下对方位和仰角定位性能的影响。
对10名听力正常的成年人在三种聆听条件下的定位进行评估：（1）正常听力（NH），（2）单侧耳塞（NH-耳塞），以及（3）单侧耳塞加信号对侧路由助听（NH-耳塞+CROS）。通过用E-A-Rsoft™ FX™泡沫耳塞堵塞耳朵来实现单耳听力模拟。刺激声由150毫秒的高通噪声脉冲串（3-20千赫）组成，以随机顺序从水平方向±70°、垂直方向±30°的五十个位置呈现，声压级分别为45、55和65分贝。
在单侧耳塞聆听条件下，参与者在仰角上表现出良好的定位能力，对于指向未堵塞耳朵的信号在方位上存在反应偏差。当信号对侧路由助听设备开启时，仰角定位性能显著下降，表现为反应增益显著降低和低值。此外，与模拟单侧听力损失条件相比，信号对侧路由助听定位在方位上的性能进一步降低。使用信号对侧路由设备还会导致听众反应的及时性降低和反应变异性增加。
结果表明，信号对侧路由助听器会干扰单耳频谱和响度线索，从而导致水平和垂直维度上的定位性能下降。反应时间增加和反应变异性增加表明，佩戴信号对侧路由设备时定位更加费力。
