Human cortical responses to the speech envelope
Human cortical responses to the speech envelope
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DOI：
10.1097/aud.0b013e31816453dc
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发表时间：
2008-04-01
期刊：
影响因子：
3.7
通讯作者：
Picton, Terence W.
中科院分区：
文献类型：
--
作者：
Aiken, Steven J.;Picton, Terence W.
目的：研究人类听觉皮层对语音时域振幅包络的反应。对语音包络的响应可能是有用的，用于验证可理解的语音的神经编码，特别是在助听器配件，因为助听器增益和压缩特性进行中的语音应该更接近真实的世界的性能比孤立的简短syllabes.Design：语音包络包括对应于音素和音节转换的能量变化。2和20 Hz之间的包络频率对语音清晰度很重要。人类事件相关电位被记录到六个不同的句子，并确定这些电位在听觉皮层的来源。为了提高信噪比超过正在进行的脑电图记录，我们平均的反应在多个介绍，并从多通道头皮记录源波形。源分析导致双侧，对称，垂直和水平偶极子在后听觉皮层。然后将源波形与句子的低频对数包络进行交叉相关。每个句子的最大相关性的显著性和潜伏期证明了大脑反应的存在和潜伏期。源波形也与基于对刺激变化的一系列重叠瞬态响应的简单模型交叉相关（对数包络的导数）。对数包络和垂直偶极子源波形之间的相关性对于所有句子和除了一个参与者之外的所有参与者都是显著的（平均r = 0.35），平均延迟为175（左）至180（右）msec。瞬态响应模型之间的关联（PI为68毫秒，NI为124毫秒，P2为208毫秒）和垂直偶极子源波形检测所有句子和所有参与者（平均r = 0.30），平均延迟为6（右）至10（左）毫秒。这些结果表明，人类的听觉皮层要么直接跟随语音包络，要么对这个包络的变化做出一致的反应。包络和响应之间的延迟约为180毫秒。
Objective: To evaluate the response of the human auditory cortex to the temporal amplitude-envelope of speech. Responses to the speech envelope could be useful for validating the neural encoding of intelligible speech, particularly during hearing aid fittings-because hearing aid gain and compression characteristics for ongoing speech should more closely resemble real world performance than for isolated brief syllables.Design: The speech envelope comprises energy changes corresponding to phonemic and syllabic transitions. Envelope frequencies between 2 and 20 Hz are important for speech intelligibility. Human event-related potentials were recorded to six different sentences and the sources of these potentials in the auditory cortex were determined. To improve the signal to noise ratio over ongoing electroen-cephalographic recordings, we averaged the responses over multiple presentations, and derived source waveforms from multichannel scalp recordings. Source analysis led to bilateral, symmetrical, vertical, and horizontal dipoles in the posterior auditory cortices. The source waveforms were then cross-correlated with the low frequency log-envelopes of the sentences. The significance and latency of the maximum correlation for each sentence demonstrated the presence and latency of the brain's response. The source waveforms were also cross-correlated with a simple model based on a series of overlapping transient responses to stimulus change (the derivative of the log-envelope).Results: Correlations between the log-envelope and vertical dipole source waveforms were significant for all sentences and for all but one of the participants (mean r = 0.35), at an average delay of 175 (left) to 180 (right) msec. Correlations between the transient response model (PI at 68 msec, NI at 124 msec, and P2 at 208 msec) and the vertical dipole source waveforms were detected for all sentences and all participants (mean r = 0.30), at an average delay of 6 (right) to 10 (left) msec.Conclusions: These results show that the human auditory cortex either directly follows the speech envelope or consistently reacts to changes in this envelope. The delay between the envelope and the response is approximately 180 msec.