Department of Neurosciences, Research Group Experimental ORL, KU Leuven-University of Leuven, Leuven, Belgium.
Faculty of Psychology and Education Sciences, Parenting and Special Education Research Unit, KU Leuven-University of Leuven, Leuven, Belgium.
Ear Hear. 2019 Sep/Oct;40(5):1242-1252. doi: 10.1097/AUD.0000000000000706.
Increasing evidence exists that poor speech perception abilities precede the phonological deficits typically observed in dyslexia, a developmental disorder in learning to read. Impaired processing of dynamic features of speech, such as slow amplitude fluctuations and transient acoustic cues, disrupts effortless tracking of the speech envelope and constrains the development of adequate phonological skills. In this study, a speech envelope enhancement (EE) strategy was implemented to reduce speech perception deficits by students with dyslexia. The EE emphasizes onset cues and reinforces the temporal structure of the speech envelope specifically.
Speech perception was assessed in 42 students with and without dyslexia using a sentence repetition task in a speech-weighted background noise. Both natural and vocoded speech were used to assess the contribution of the temporal envelope on the speech perception deficit. Their envelope-enhanced counterparts were added to each baseline condition to administer the effect of the EE algorithm. In addition to speech-in-noise perception, general cognitive abilities were assessed.
Results demonstrated that students with dyslexia not only benefit from EE but benefit more from it than typical readers. Hence, EE completely normalized speech reception thresholds for students with dyslexia under adverse listening conditions. In addition, a correlation between speech perception deficits and phonological processing was found for students with dyslexia, further supporting the relation between speech perception abilities and reading skills. Similar results and relations were found for conditions with natural and vocoded speech, providing evidence that speech perception deficits in dyslexia stem from difficulties in processing the temporal envelope.
Using speech EE, speech perception skills in students with dyslexia were improved passively and instantaneously, without requiring any explicit learning. In addition, the observed positive relationship between speech processing and advanced phonological skills opens new avenues for specific intervention strategies that directly target the potential core deficit in dyslexia.
越来越多的证据表明，在阅读障碍等发育性学习障碍中，通常观察到的语音缺陷之前，存在较差的语音感知能力。语音动态特征（如缓慢的幅度波动和瞬态声学线索）处理受损，破坏了语音包络的轻松跟踪，并限制了适当语音技能的发展。在这项研究中，实施了语音包络增强（EE）策略，以减少阅读障碍学生的语音感知缺陷。EE 强调起始线索，并特别增强语音包络的时间结构。
使用语音加权背景噪声中的句子重复任务评估 42 名有阅读障碍和无阅读障碍的学生的语音感知能力。使用自然语音和语音编码语音来评估时间包络对语音感知缺陷的贡献。将它们的包络增强对应物添加到每个基线条件中，以管理 EE 算法的效果。除了语音感知能力外，还评估了一般认知能力。
结果表明，阅读障碍学生不仅受益于 EE，而且比典型读者受益更多。因此，EE 在不利的听力条件下完全使阅读障碍学生的语音接收阈值正常化。此外，还发现阅读障碍学生的语音感知缺陷与语音处理之间存在相关性，进一步支持了语音感知能力与阅读技能之间的关系。在自然语音和语音编码语音条件下也发现了类似的结果和关系，这表明阅读障碍中的语音感知缺陷源于处理时间包络的困难。
使用语音 EE，阅读障碍学生的语音感知能力得到了被动和即时的改善，而无需任何明确的学习。此外，语音处理与高级语音技能之间的观察到的正相关关系为直接针对阅读障碍潜在核心缺陷的特定干预策略开辟了新途径。
