Speech-ABR安静及噪声环境下音位的对比研究

摘要

目的：对比speech-ABR在安静及噪声环境下单音节声母、韵母及声调的变化，研究噪声对单音节音位的影响。方法招募正常听力受试者40例（男20例，女20例），母语为汉语普通话。Speech-ABR刺激声为260ms时程的合成言语声/mi/，声调为三声，刺激强度为70dB SPL，记录右耳安静状态下及噪声状态下（信噪比SNR=-10dB）speech-ABR的反应波形。对比起始反应波形(onset response, OR)、过渡反应波形(consonant-to-vowel transition)及频率跟随反应波形（frequency following response,FFR）的潜伏期的变化。并对比安静及噪声状态下声调追踪（pitch tracking）相关系数r的变化。使用SPSS18.0软件进行数据统计分析,数据采用配对t检验分析两组的差异,P<0.05时为差异有统计学意义。结果260ms时程/mi/诱发的言语听性脑干反应波形特征，主要由潜伏期为10ms内的起始反应、潜伏期为80-220ms内的频率跟随反应及最后的终止反应组成，以及潜伏期在10-80ms内的辅音-元音过渡反应。其中起始反应部分为辅音部分所诱发；过渡反应部分为辅-元音的过渡信息诱发；由/mi/中的元音部分所诱发的频率跟随反应部分共由15个波形组成。经配对t检验分析，在安静及噪声环境下进行对比，起始反应峰值（辅音部分）平均潜伏期延长0.85±0.17ms(P=0.000)。过度反应峰值平均潜伏期延长0.75±0.15ms((P=0.000)。频率跟随反应峰值平均潜伏期延长0.38±0.10ms(P=0.000），结果均具有统计学意义。安静环境下声调追踪反应相关系数r均值为0.84±0.08，噪声环境下相关系数r均值为0.74±0.12，两者对比结果具有统计学意义（(P=0.000）。结论在噪声环境下，测试音的辅音、元音对应波形潜伏期均发生变化，声调追踪系数会有所下降，提示三种音位均会受到噪声的影响。与以往主观的言语识别率测试方式及诱发电位测试相比，speech-ABR是一种客观方式评估言语声受到噪声干扰情况的测试方法。%Objective The aim of the study was to compare speech-ABR results with changes of vowel, consonant and pitch of monosyllables under quiet and noise circumstances. Methods Forty Mandarin speaking subjects (20 males, 20 fe-males) with normal hearing were recruited. The stimulus of speech-ABR was/mi/with a duration of 260 ms and down-up pitch, delivered to the right ear at 70 dB SPL. The peaks of response waves were labeled. The latencies of onset response (OR), consonant-to-vowel transition (CV) and frequency following response (FFR) were analyzed under quiet and noisy (SNR=-10 dB) circumstances, and correlation coefficients of pitch tracking were compared. The SPSS 18.0 software was used for statistical analysis. Paired sample t-test was used for two group comparisons. Statistical significance was defined as P<0.05. Results Brainstem responses elicited by/mi/were composed of four parts:an onset response (10 ms), a transitional response (10-80 ms), a frequency following response (80-220 ms) and an offset response. The onset response was evoked by the consonant and the transitional response by consonant-to-vowel transition. The frequency following response, evoked by the vowel, was composed of fifteen response waves. A series of featured waves were observed. The change of average la-tency of the onset response wave was 0.85±0.17 ms (P=0.000). The change of average latency of consonant-to-vowel transi-tion wave was 0.75±0.15 ms (P=0.000), and the change of average latency of frequency following response wave was 0.38± 0.10 ms (P=0.000). Furthermore, the correlation coefficient of pitch tracking was 0.84 ± 0.08 under quiet environment and 0.74±0.12 under noisy environment (P=0.000). Conclusions Noise can change latencies of the consonant and vowel, and re-duce correlation coefficient of pitch tracking. These results suggest that the three phonemes can be affected by noise. Com-pared with the subjective evoked potentials in previous reports, speech-ABR is more sensitive and objective to detect differ-ences in auditory recognition against noise background..