Kumar Durga S, Konadath Sreeraj
J Am Acad Audiol. 2025 Jun 6;36(4):238-47. doi: 10.3766/jaaa.240102.
The behavioral investigation of compressive nonlinearity (CNL) can be achieved by comparing the growth of forward masking (FM) between on-frequency and off-frequency maskers. Because the off-frequency masker exhibits linear behavior at the characteristic frequency whereas the on-frequency masker functions nonlinearly, comparing the experimental outcomes using scalp-recorded auditory brainstem response (ABR) measures provides an objective estimation of auditory physiology. The study aimed to examine CNL using ABR parameters, such as Vth peak latency or amplitude, using probe stimuli frequencies ranging from 0.5–4 kilohertz (kHz), which employs both on- and off-frequency FM methods. An experimental within-group research design was adopted for the study. The study was conducted in 31 healthy individuals aged 18–45 years (mean age of 27.88 ± 8.589 years). The ABR was recorded employing a tone-on-tone FM paradigm for probe stimuli frequencies ranging from 0.5–4 kHz. The experiment was done under unmasked and forward-masked conditions (on- and off-frequency FM with varying masker intensity from 50–80 decibels [dB] sound pressure level [SPL]). The data for latency and amplitude were statistically analyzed using one-way repeated measures analysis of variance (RM-ANOVA), two-way RM-ANOVA, and Bonferroni post hoc tests between and within different probe stimuli in different conditions. Further, a paired test compared the slope across FM conditions. A gradual shift in Vth peak latency and a reduction in response amplitude was observed in proportion to the increase in masker intensity for both masking conditions across all probe stimuli, with a more pronounced shift in on-frequency FM. However, no significant difference in latency was found between the masker intensities of 60–70 dB SPL in either masking condition. Additionally, the growth of masking showed a steep slope in the on-frequency FM with a smaller ² value. Objective electrophysiologic measures are instrumental in accurately estimating CNL because these measures provide robust, efficient, and reliable insights into the intricate functioning of the auditory system without reliance on a subjective behavioral response.
压缩非线性（CNL）的行为学研究可以通过比较同频掩蔽和异频掩蔽之间前掩蔽（FM）的增长情况来实现。由于异频掩蔽在特征频率处表现出线性行为，而同频掩蔽呈非线性作用，因此使用头皮记录的听觉脑干反应（ABR）测量方法比较实验结果，可以对听觉生理学进行客观评估。本研究旨在使用ABR参数（如Vth峰潜伏期或振幅），采用0.5-4千赫兹（kHz）的探测刺激频率，运用同频和异频FM方法来研究CNL。本研究采用组内实验研究设计。研究对象为31名年龄在18-45岁（平均年龄27.88 ± 8.589岁）的健康个体。采用纯音对纯音FM范式记录0.5-4 kHz探测刺激频率的ABR。实验在无掩蔽和前掩蔽条件下进行（同频和异频FM，掩蔽强度从50-80分贝[dB]声压级[SPL]变化）。使用单向重复测量方差分析（RM-ANOVA）、双向RM-ANOVA以及不同条件下不同探测刺激之间和内部的Bonferroni事后检验对潜伏期和振幅数据进行统计分析。此外，配对t检验比较了FM条件下的斜率。在所有探测刺激的两种掩蔽条件下，随着掩蔽强度的增加，均观察到Vth峰潜伏期逐渐变化以及反应振幅减小，同频FM中的变化更为明显。然而，在任一掩蔽条件下，60-70 dB SPL的掩蔽强度之间在潜伏期上未发现显著差异。此外，同频FM中的掩蔽增长显示出更陡的斜率，且较小。客观电生理测量有助于准确估计CNL，因为这些测量能够在不依赖主观行为反应的情况下，为听觉系统的复杂功能提供有力、高效且可靠的见解。
