1 ExpORL, Department of Neurosciences, KU Leuven, Belgium.
Trends Hear. 2018 Jan-Dec;22:2331216518805363. doi: 10.1177/2331216518805363.
In Part I, we investigated 40-Hz auditory steady-state response (ASSR) amplitudes for the use of objective loudness balancing across the ears for normal-hearing participants and found median across-ear ratios in ASSR amplitudes close to 1. In this part, we further investigated whether the ASSR can be used to estimate binaural loudness balance for listeners with asymmetric hearing, for whom binaural loudness balancing is of particular interest. We tested participants with asymmetric hearing and participants with bimodal hearing, who hear with electrical stimulation through a cochlear implant (CI) in one ear and with acoustical stimulation in the other ear. Behavioral loudness balancing was performed at different percentages of the dynamic range. Acoustical carrier frequencies were 500, 1000, or 2000 Hz, and CI channels were stimulated in apical or middle regions in the cochlea. For both groups, the ASSR amplitudes at balanced loudness levels were similar for the two ears, with median ratios between left and right ear stimulation close to 1. However, individual variability was observed. For participants with asymmetric hearing loss, the difference between the behavioral balanced levels and the ASSR-predicted balanced levels was smaller than 10 dB in 50% and 56% of cases, for 500 Hz and 2000 Hz, respectively. For bimodal listeners, these percentages were 89% and 60%. Apical CI channels yielded significantly better results (median difference near 0 dB) than middle CI channels, which had a median difference of -7.25 dB.
在第一部分中，我们研究了 40-Hz 听觉稳态响应（ASSR）的幅度，以在正常听力参与者的耳朵之间实现客观响度平衡，并发现 ASSR 幅度的双耳比接近 1。在这一部分，我们进一步研究了 ASSR 是否可用于估计具有不对称听力的听众的双耳响度平衡，对于这些听众，双耳响度平衡尤为重要。我们测试了具有不对称听力的参与者和具有双模式听力的参与者，他们通过耳蜗植入物（CI）在一只耳朵中用电刺激，在另一只耳朵中用声学刺激来听。在不同的动态范围百分比下进行行为响度平衡。声学载波频率为 500、1000 或 2000 Hz，CI 通道在耳蜗的顶端或中部区域被刺激。对于这两个组，在平衡响度水平下的 ASSR 幅度在两个耳朵之间相似，左耳和右耳刺激的中位数比接近 1。然而，观察到个体差异。对于具有不对称听力损失的参与者，在 500 Hz 和 2000 Hz 下，行为平衡水平和 ASSR 预测平衡水平之间的差异分别小于 10 dB 的比例为 50%和 56%。对于双模式听众，这些百分比分别为 89%和 60%。顶端 CI 通道产生的结果明显更好（中位数差异接近 0 dB），而中间 CI 通道的中位数差异为-7.25 dB。
