Speech envelope following responses in children (Easwar et al., 2022)

<strong>Purpose:</strong> Envelope following responses (EFRs) could be useful for objectively evaluating audibility of speech in children who are unable to participate in routine clinical tests. However, relative to adults, the characteristics of EFRs elicited by frequency-specific speech and their utility in predicting audibility in children are unknown. <strong>Method: </strong>EFRs were elicited by the first (F1) and second and higher formants (F2+) of male-spoken vowels /u/ and /i/ and by fricatives /ʃ/ and /s/ in the token /suʃi/ presented at 15, 35, 55, 65, and 75 dB SPL. The F1, F2+, and fricatives were low-, mid-, and high-frequency dominant, respectively. EFRs were recorded between the vertex and the nape from twenty-three 6- to 17-year-old children and 21 young adults with normal hearing. Sensation levels of stimuli were estimated based on behavioral thresholds. <strong>Results:</strong> In children, amplitude decreased with age for /ʃ/-elicited EFRs but remained stable for low- and mid-frequency stimuli. As a group, EFR amplitude and phase coherence did not differ from that of adults. EFR sensitivity (proportion of audible stimuli detected) and specificity (proportion of inaudible stimuli not detected) did not vary between children and adults. Consistent with previous work, EFR sensitivity increased with stimulus frequency and level. The type of statistical indicator used for EFR detection did not influence accuracy in children. <strong>Conclusions:</strong> Adultlike EFRs in 6- to 17-year-old typically developing children suggest mature envelope encoding for low- and mid-frequency stimuli. EFR sensitivity and specificity in children, when considering a wide range of stimulus levels and audibility, are ~77% and ~92%, respectively. <br> <strong>Supplemental Material S1. </strong>EFR sensitivity (Table 1A) and specificity (Table 1B) at each level for each stimulus and statistical indicator in children and adults. <br> Easwar, V., Purcell, D., Lasarev, M., McGrath, E., &amp; Galloy, M. (2022). Speech-evoked envelope following responses in children and adults. <em>Journal of Speech, Language, and Hearing Research.</em> Advance online publication. https://doi.org/10.1044/2022_JSLHR-22-00156

**研究目的：** 包络跟随反应（Envelope Following Responses, EFRs）可用于客观评估无法参与常规临床测试的儿童的言语可听度。然而，相较于成人，由频率特异性言语诱发的包络跟随反应的特征，以及其在预测儿童言语可听度方面的效用，目前尚不明确。
**研究方法：** 本研究采用男性发音的元音/u/和/i/的第一共振峰（F1）、第二及以上共振峰（F2+），以及词汇/suʃi/中的擦音/ʃ/和/s/作为刺激声，刺激声的声压级分别为15、35、55、65和75 dB SPL。其中F1、F2+和擦音分别为低频主导、中频主导和高频主导成分。研究招募了23名6至17岁的儿童与21名听力正常的青年成人，在顶点与颈后之间记录其EFRs。刺激声的感觉级基于行为听阈进行估算。
**研究结果：** 在儿童群体中，由/ʃ/诱发的EFR振幅随年龄增长而降低，但低频与中频刺激诱发的EFR振幅保持稳定。整体而言，儿童与成人的EFR振幅及相位相干性无显著差异。EFR的敏感度（即检测到的可听刺激占比）与特异度（即未被检测到的不可听刺激占比）在儿童与成人之间无明显变化。与既往研究结果一致，EFR敏感度随刺激声频率与强度的升高而提升。用于EFR检测的统计指标类型，不会影响儿童的检测准确性。
**研究结论：** 6至17岁的典型发育儿童的EFR特征与成人相似，表明其对低频与中频刺激的包络编码已发育成熟。在涵盖广泛刺激强度与可听度范围的前提下，儿童的EFR敏感度与特异度分别约为77%和92%。
**补充材料S1：** 儿童与成人在各刺激强度下，针对每种刺激与统计指标的EFR敏感度（表1A）与特异度（表1B）。
Easwar, V., Purcell, D., Lasarev, M., McGrath, E., & Galloy, M. (2022). 儿童与成人的言语诱发包络跟随反应. *《言语、语言与听力研究杂志》*, 在线提前发表. https://doi.org/10.1044/2022_JSLHR-22-00156