Abnormal cortical processing of the syllable rate of speech in poor readers.
Abnormal cortical processing of the syllable rate of speech in poor readers.
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DOI：
10.1523/jneurosci.5242-08.2009
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发表时间：
2009-06-17
期刊：
影响因子：
--
通讯作者：
Kraus N
中科院分区：
文献类型：
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作者：
Abrams DA;Nicol T;Zecker S;Kraus N
有阅读障碍的儿童长期以来一直与快速呈现的声音刺激的知觉受损有关，最近出现了慢速特征的缺陷。目前尚不清楚低频声学特征的损害是否会对阅读障碍个体的语音处理产生负面影响。在这里，我们提供了神经生理学证据，表明糟糕的读者损害了语音包络的表征，语音包络是在语音中提供音节模式信息的声学线索。我们测量了大脑皮质诱发电位对句子刺激的反应，发现好的读者在所有语音包络表征的测量中都显示出一致的右半球在听觉皮质的优势，包括皮质反应的精确度、时间和幅度。阅读能力差的人在语音包络表征的所有测量中都表现出大脑不对称的异常模式。此外，对语音包络表征的皮质测量预测了标准化阅读分数的44%的变异性，以及各种能力的语音处理测量的50%的变异性。研究结果有力地支持了声学水平处理和高级语言能力之间的关系，并首次将阅读能力与语音信号中低频声学特征的皮质处理联系起来。结果还支持这样的假设，即大脑两个半球之间的不对称路径代表了人类听觉系统中时间编码的重要机制，以及需要扩展阅读障碍的时间处理假说，以涵盖比先前承认的更广泛的语音特征的损害。
Children with reading impairments have long been associated with impaired perception for rapidly presented acoustic stimuli and recently have shown deficits for slower features. It is not known whether impairments for low-frequency acoustic features negatively impact processing of speech in reading impaired individuals. Here we provide neurophysiological evidence that poor readers have impaired representation of the speech envelope, the acoustical cue that provides syllable pattern information in speech. We measured cortical-evoked potentials in response to sentence stimuli and found that good readers indicated consistent right-hemisphere dominance in auditory cortex for all measures of speech envelope representation, including the precision, timing and magnitude of cortical responses. Poor readers showed abnormal patterns of cerebral asymmetry for all measures of speech envelope representation. Moreover, cortical measures of speech envelope representation predicted up to 44% of the variability in standardized reading scores and 50% in measures of phonological processing across a wide range of abilities. Findings strongly support a relationship between acoustic-level processing and higher-level language abilities, and are the first to link reading ability with cortical processing of low-frequency acoustic features in the speech signal. Results also support the hypothesis that asymmetric routing between cerebral hemispheres represents an important mechanism for temporal encoding in the human auditory system, and the need for an expansion of the temporal processing hypothesis for reading-disabilities to encompass impairments for a wider range of speech features than previously acknowledged.