Department of Audiology and Speech Language Pathology, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, Mangaluru, Karnataka, 575001, India.
Department of Audiology, Trustwell Hospital Pvt. Limited, Bangalore, Karnataka, 560002, India.
F1000Res. 2020 Feb 13;9:115. doi: 10.12688/f1000research.21379.1. eCollection 2020.
The temporal envelope (ENV) plays a vital role in conveying inter-aural time difference (ITD) in many clinical populations. However, the presence of background noise and electronic features, such as compression, reduces the modulation depth of ENV to a different degree in both ears. The effect of ENV modulation depth differences between the ears on ITD thresholds is unknown; therefore, this was the aim of the current study's investigation. Six normally hearing young adults (age range 20-30 years) participated in the current study. Six vowel-consonant-vowel (VCV) (/aka/, /aga/, /apa/, /aba/, /ata/, /ada/) tokens were used as the probe stimuli. ENV depth of VCV tokens was smeared by 0%, 29%, and 50%, which results in 100%, 71%, and 50% of the original modulation depth. ITD thresholds were estimated as a function of the difference in temporal ENV depth between the ears, wherein in one ear the modulation depth was retained at 100% and in the other ear, the modulation depth was changed to 100%, 71%, and 50%. Repeated measures of ANOVA revealed a significant main effect of interaural modulation depth differences on the ITD threshold (F(2,10)= 9.04, p= 0.006). ITD thresholds increased with an increase in the inter-aural modulation depth difference. Inter-aural ENV depth is critical for ITD perception.
时间包络 (ENV) 在许多临床人群中对传达耳间时间差 (ITD) 起着至关重要的作用。然而，背景噪声和电子特征（如压缩）的存在会以不同程度降低双耳 ENV 的调制深度。双耳 ENV 调制深度差异对 ITD 阈值的影响尚不清楚；因此，这是当前研究调查的目的。
本研究共有 6 名听力正常的年轻成年人（年龄范围 20-30 岁）参与。6 个元音-辅音-元音 (VCV) (/aka/, /aga/, /apa/, /aba/, /ata/, /ada/) 音位被用作探测刺激。VCV 音位的 ENV 深度分别被涂抹 0%、29%和 50%，分别对应于原始调制深度的 100%、71%和 50%。ITD 阈值作为双耳时间 ENV 深度差异的函数进行估计，其中一只耳朵的调制深度保持在 100%，另一只耳朵的调制深度分别改变为 100%、71%和 50%。重复测量方差分析显示，耳间调制深度差异对 ITD 阈值有显著的主效应 (F(2,10)=9.04, p=0.006)。ITD 阈值随耳间调制深度差异的增加而增加。
耳间 ENV 深度对 ITD 感知至关重要。
