Zhang Fawen, Underwood Gabrielle, McGuire Kelli, Liang Chun, Moore David R, Fu Qian-Jie
Department of Communication Sciences and Disorders, University of Cincinnati, Ohio, USA.
Department of Communication Sciences and Disorders, University of Cincinnati, Ohio, USA.
Hear Res. 2019 Aug;379:12-20. doi: 10.1016/j.heares.2019.04.007. Epub 2019 Apr 17.
Dynamic frequency changes in sound provide critical cues for speech perception. Most previous studies examining frequency discrimination in cochlear implant (CI) users have employed behavioral tasks in which target and reference tones (differing in frequency) are presented statically in separate time intervals. Participants are required to identify the target frequency by comparing stimuli across these time intervals. However, perceiving dynamic frequency changes in speech requires detection of within-interval frequency change. This study explored the relationship between detection of within-interval frequency changes and speech perception performance of CI users. Frequency change detection thresholds (FCDTs) were measured in 20 adult CI users using a 3-alternative forced-choice (3AFC) procedure. Stimuli were 1-sec pure tones (base frequencies at 0.25, 1, 4 kHz) with frequency changes occurring 0.5 s after the tone onset. Speech tests were 1) Consonant-Nucleus-Consonant (CNC) monosyllabic word recognition, 2) Arizona Biomedical Sentence Recognition (AzBio) in Quiet, 3) AzBio in Noise (AzBio-N, +10 dB signal-to-noise/SNR ratio), and 4) Digits-in-noise (DIN). Participants' subjective satisfaction with the CI was obtained. Results showed that correlations between FCDTs and speech perception were all statistically significant. The satisfaction level of CI use was not related to FCDTs, after controlling for major demographic factors. DIN speech reception thresholds were significantly correlated to AzBio-N scores. The current findings suggest that the ability to detect within-interval frequency changes may play an important role in speech perception performance of CI users. FCDT and DIN can serve as simple and rapid tests that require no or minimal linguistic background for the prediction of CI speech outcomes.
声音中的动态频率变化为语音感知提供了关键线索。以往大多数研究耳蜗植入（CI）使用者频率辨别能力的实验都采用行为任务，即目标音和参考音（频率不同）在不同的时间间隔内静态呈现。参与者需要通过比较这些时间间隔内的刺激来识别目标频率。然而，感知语音中的动态频率变化需要检测间隔内的频率变化。本研究探讨了间隔内频率变化检测与CI使用者语音感知表现之间的关系。采用三选一强制选择（3AFC）程序，测量了20名成年CI使用者的频率变化检测阈值（FCDT）。刺激为1秒的纯音（基频分别为0.25、1、4kHz），频率变化在音调开始后0.5秒出现。语音测试包括：1）辅音-元音-辅音（CNC）单音节词识别；2）安静环境下的亚利桑那生物医学句子识别（AzBio）；3）噪声环境下的AzBio（AzBio-N，信噪比为+10dB）；4）噪声中的数字（DIN）。获取了参与者对CI的主观满意度。结果表明，FCDT与语音感知之间的相关性均具有统计学意义。在控制了主要人口统计学因素后，CI使用的满意度水平与FCDT无关。DIN语音接收阈值与AzBio-N得分显著相关。目前的研究结果表明，检测间隔内频率变化的能力可能在CI使用者的语音感知表现中起重要作用。FCDT和DIN可作为简单快速的测试，无需或只需极少的语言背景知识即可预测CI的语音效果。
