Department of Otolaryngology-Head and Neck Surgery, College of Medicine, The Ohio State University, Columbus, Ohio, USA.
Department of Audiology, Nationwide Children's Hospital, Columbus, Ohio, USA.
Ear Hear. 2022;43(6):1761-1770. doi: 10.1097/AUD.0000000000001244. Epub 2022 Oct 18.
This study investigated the effects of two temporal response properties of the auditory nerve (i.e., neural adaptation and recovery from neural adaptation) on speech perception performance in postlingually deafened adult cochlear implant (CI) users.
Study participants included 18 postlingually deafened adults who were Cochlear Nucleus device users with a full electrode array insertion in the test ear(s). Neural adaptation and adaptation recovery of the auditory nerve (AN) were evaluated using electrophysiological measures of the electrically evoked compound action potential (eCAP). The amount of neural adaptation was quantified by the adaptation index within three time windows: 0 to 8.89 (window 1), 44.44 to 50.00 (window 2), and 94.44 to 100.00 ms (window 3). The speed of neural adaptation was estimated using a two-parameter power law function. To evaluate adaptation recovery of the AN, eCAPs to the last pulse of the 100-ms pulse train were recorded at masker-probe-intervals ranging from 1.054 to 256 ms in logarithmic steps. The amount of adaptation recovery was quantified by the adaptation recovery ratio. The time-constant of adaptation recovery was estimated using an exponential function with up to three components. Speech perception performance was evaluated by measuring consonant-nucleus-consonant (CNC) word scores presented in quiet and in speech-shaped noise at a signal-to-noise ratio (SNR) of +10 dB. One-tailed Pearson Product Moment correlation tests were used (1) to assess the associations among parameters of neural adaptation and adaptation recovery and (2) to evaluate the strength of association between these parameters and CNC word scores measured in quiet and in noise. The contributions of different parameters quantifying neural adaptation and adaptation recovery on speech perception scores were evaluated using multivariable linear regression analyses.
The Pearson Product Moment correlation coefficient demonstrated a moderate, negative correlation between the speed of adaptation recovery and CNC word scores measured in quiet and in noise. The speed of adaptation recovery accounted for 14.1% of variability in CNC word scores measured in quiet and 16.7% of variability in CNC word scores measured in noise. The correlation strengths between CNC word scores and the adaptation index, the adaptation recovery ratio and the speed of neural adaptation ranged from negligible to weak.
The speed of adaptation recovery plays a more important role than other features of neural adaptation and adaptation recovery of the AN in speech perception in postlingually deafened adult CI users. Patients with prolonged adaptation recovery tend to show poorer speech perception performance.
本研究旨在探讨听觉神经（即神经适应和神经适应恢复）的两种时程反应特性对语后聋成年人工耳蜗（CI）使用者言语感知表现的影响。
研究参与者包括 18 名语后聋的成年人，他们是 Cochlear Nucleus 设备使用者，在测试耳中插入了全电极阵列。使用电诱发复合动作电位（eCAP）的电生理学测量来评估听觉神经（AN）的神经适应和适应恢复。在三个时间窗口内量化神经适应的程度：0 至 8.89ms（窗口 1）、44.44 至 50.00ms（窗口 2）和 94.44 至 100.00ms（窗口 3）。使用双参数幂律函数估计神经适应的速度。为了评估 AN 的适应恢复，在掩蔽-探测间隔从 1.054 到 256ms 以对数步长的情况下，记录 100ms 脉冲串的最后一个脉冲的 eCAP。通过适应恢复比来量化适应恢复的程度。使用具有三个分量的指数函数来估计适应恢复的时间常数。在+10dB 的信噪比（SNR）下，通过测量安静和语音噪声中的辅音-核-辅音（CNC）单词得分来评估言语感知表现。使用单尾 Pearson 积矩相关检验（1）评估神经适应和适应恢复参数之间的关联，（2）评估这些参数与安静和噪声中测量的 CNC 单词得分之间的关联强度。使用多变量线性回归分析评估量化神经适应和适应恢复的不同参数对言语感知得分的贡献。
Pearson 积矩相关系数表明，适应恢复速度与安静和噪声中测量的 CNC 单词得分之间存在中等负相关。适应恢复速度解释了安静时测量的 CNC 单词得分的 14.1%的变异性和噪声中测量的 CNC 单词得分的 16.7%的变异性。CNC 单词得分与适应指数、适应恢复比和神经适应速度之间的相关强度从微不足道到弱不等。
在语后聋成年 CI 使用者的言语感知中，适应恢复速度比听觉神经的其他适应和适应恢复特征更为重要。适应恢复时间延长的患者往往表现出较差的言语感知表现。
