Huber Jonas, Schoof Tim, Stewart Hannah, de Cheveigné Alain, Rosen Stuart
Department of Speech, Hearing and Phonetic Sciences, UCL, UK.
Department of Psychology, Lancaster University, United Kingdom.
bioRxiv. 2025 May 21:2025.05.20.655073. doi: 10.1101/2025.05.20.655073.
Frequency-Following Responses (FFRs) are typically recorded using stimuli of 40-250 ms in duration separated by silent intervals. Because robust FFRs require averaging across approximately 3000 stimulus repetitions, conventional acquisition is time-intensive. We introduce the Rapid FFR, a technique that minimises recording time by presenting the stimulus continuously (i.e., without inter-stimulus intervals) and by averaging across individual response cycles. This study aimed to: (a) compare Rapid and Conventional FFR performance under time-matched conditions; (b) assess test-retest reliability of both methods, and (c) examine potential neural adaptation during extended Rapid FFR recordings.
All participants (37 in total) were young adults with clinically normal hearing. In Experiment 1, FFRs were elicited from 16 listeners using a 128 Hz sawtooth wave presented in two ways: (1) continuously over approximately 1 minute in each polarity for the Rapid FFR and (2) as discrete tone bursts (1500 trials per polarity) for the standard FFR. Signal-to-Noise ratios (SNRs), response amplitudes, and test-retest reliability were compared across techniques. In Experiment 2, the Rapid FFR was recorded continuously from 21 listeners for nearly nine minutes to assess potential adaptation over time.
The Rapid FFR produced significantly higher SNRs than the standard FFR, reflecting improved recording efficiency. Both techniques captured inter-individual differences reliably, with comparable frequency-domain response patterns across participants. In particular, measures derived from the Rapid FFR showed strong agreement with those from the standard FFR for lower harmonics (F0-H3). Higher harmonics (H4-H7) exhibited greater variability but remained consistent between techniques. In the prolonged recording condition, FFR amplitudes remained stable over time, with no significant decline across the nine minute recording. This indicates that continuous stimulation did not result in measurable neural adaptation or response fatigue.
The Rapid FFR offers a time-efficient alternative to standard protocols, preserving signal fidelity and reliability while enabling shorter acquisition times. These findings suggest that the Rapid FFR is well-suited for use in populations where long recordings are challenging (e.g., in infants and the clinic) and can facilitate more extensive experimental designs within a single session. The method holds promise for advancing both research and clinical applications of the FFR. Future studies should explore its use across a broader range of sounds (in particular, dynamically varying ones) and listener groups.
频率跟随反应（FFR）通常使用持续时间为40 - 250毫秒且被静音间隔隔开的刺激来记录。由于可靠的FFR需要对大约3000次刺激重复进行平均，传统采集方式耗时较长。我们引入了快速FFR技术，该技术通过连续呈现刺激（即无刺激间隔）并对各个反应周期进行平均来最小化记录时间。本研究旨在：（a）在时间匹配条件下比较快速FFR和传统FFR的性能；（b）评估两种方法的重测信度；（c）检查在长时间快速FFR记录过程中潜在的神经适应性。
所有参与者（共37名）均为听力临床正常的年轻人。在实验1中，使用128赫兹锯齿波以两种方式从16名听众中引出FFR：（1）以快速FFR的方式在每个极性下连续呈现约1分钟；（2）以标准FFR的方式作为离散音爆（每个极性1500次试验）。比较了不同技术之间的信噪比（SNR）、反应幅度和重测信度。在实验2中，从21名听众中连续记录快速FFR近9分钟，以评估随时间的潜在适应性。
快速FFR产生的SNR显著高于标准FFR，这反映了记录效率的提高。两种技术都能可靠地捕捉个体间差异，参与者的频域反应模式具有可比性。特别是，从快速FFR得出的测量值与标准FFR在较低谐波（F0 - H3）方面显示出高度一致性。较高谐波（H4 - H7）表现出更大的变异性，但在不同技术之间保持一致。在长时间记录条件下，FFR幅度随时间保持稳定，在9分钟的记录过程中没有显著下降。这表明连续刺激不会导致可测量的神经适应性或反应疲劳。
快速FFR为标准方案提供了一种省时的替代方法，在保证信号保真度和可靠性的同时实现了更短的采集时间。这些发现表明，快速FFR非常适合用于长时间记录具有挑战性的人群（例如婴儿和临床患者），并且可以在单个会话中促进更广泛的实验设计。该方法有望推动FFR在研究和临床应用方面的发展。未来的研究应探索其在更广泛的声音（特别是动态变化的声音）和听众群体中的应用。
