噪聲環境下刺激速率對廣東語聲調認知能力的影響

Abstract

目的: 探讨人工耳蜗装置中刺激速率的改变对人工耳蜗植入者在噪声环境下对广东话声调认知能力的影响。 方法: 受试对象为18例以广东话为母语的成人人工耳蜗植入者。实验选取1515，800 和400脉冲/秒/通道以分别代表高、中、低3种不同刺激速率。在随机选取一种刺激速率后，患者需要在安静及不同信噪比的噪声环境下分别完成对广东话声调辨别能力及识别能力的测试。结果: 在安静及不同信噪比的噪声环境下，两项声调认知能力测试的成绩均随刺激速率的减低而下降。在0，＋5及+10的信噪比下，高速率刺激与低速率刺激下的声调辨别能力的测试成绩存在显著性差异。在-5 及0 的信噪比下，高速率刺激与低速率刺激下的声调识别能力测试成绩存在显著性差异。结论: 高速率刺激可以为人工耳蜗植入者提供更好的时间信息，有助于提高在噪声环境下的广东话声调认知能力。

OBJECTIVE: To evaluate the effects of stimulation rate on Cantonese tone perception performance against a background noise by Cantonese-speaking cochlear implant users. METHODS: Eighteen adult Cantonese-speakers with cochlear implantation participated in this study. All subjects had at least six-month experience in using the MED-EL tempo + cochlear implant device with the continuous interleaved sampling speech coding strategy. Three stimulation rates of 1515, 800 and 400 pulses per second per channel were selected to represent high, moderate and low stimulation rate conditions, respectively. Two speech tests-tone discrimination test and tone identification test were used to evaluate the effects of stimulation rate in this study. After being randomly assigned to each of the stimulation rate, the subjects were required to listen to a randomized list of speech tests presented in quiet and against a background noise of different signal-to-noise ratios. RESULTS: High stimulation rate resulted in better tone perception than low stimulation rate. For the tone discrimination test, significant differences were observed between high and low stimulation rates at signal-to-noise ratios of 0, +5, and +10 dB. For the tone identification test, there were significant differences between high and low stimulation rates at signal-to-noise ratios of -5 and 0 dB. CONCLUSION: A high stimulation rate may provide better temporal and spectral information, which is important for Cantonese tone perception against a background noise.