Max Planck Research Group Auditory Cognition, Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstrasse 1A, 04103 Leipzig, Germany.
Neuropsychologia. 2012 Jul;50(9):2154-64. doi: 10.1016/j.neuropsychologia.2012.05.013. Epub 2012 May 18.
Noise-vocoded speech is a spectrally highly degraded signal, but it preserves the temporal envelope of speech. Listeners vary considerably in their ability to adapt to this degraded speech signal. Here, we hypothesised that individual differences in adaptation to vocoded speech should be predictable by non-speech auditory, cognitive, and neuroanatomical factors. We tested 18 normal-hearing participants in a short-term vocoded speech-learning paradigm (listening to 100 4-band-vocoded sentences). Non-speech auditory skills were assessed using amplitude modulation (AM) rate discrimination, where modulation rates were centred on the speech-relevant rate of 4 Hz. Working memory capacities were evaluated (digit span and nonword repetition), and structural MRI scans were examined for anatomical predictors of vocoded speech learning using voxel-based morphometry. Listeners who learned faster to understand degraded speech also showed smaller thresholds in the AM discrimination task. This ability to adjust to degraded speech is furthermore reflected anatomically in increased grey matter volume in an area of the left thalamus (pulvinar) that is strongly connected to the auditory and prefrontal cortices. Thus, individual non-speech auditory skills and left thalamus grey matter volume can predict how quickly a listener adapts to degraded speech.
噪声编码语音是一种频谱高度退化的信号，但它保留了语音的时域包络。听众在适应这种退化语音信号的能力上存在很大差异。在这里，我们假设对编码语音的适应个体差异可以通过非语音听觉、认知和神经解剖因素来预测。我们在一个短期的编码语音学习范式中测试了 18 名正常听力的参与者（听 100 个 4 带编码句子）。使用幅度调制（AM）率辨别来评估非语音听觉技能，其中调制率集中在与语音相关的 4 Hz 速率上。使用数字跨度和非单词重复来评估工作记忆能力，并使用基于体素的形态计量学来检查结构 MRI 扫描，以寻找编码语音学习的解剖学预测因子。那些更快地学会理解退化语音的听众在 AM 辨别任务中的阈值也更小。这种适应退化语音的能力在解剖学上反映在左丘脑（丘脑枕）的一个区域的灰质体积增加，该区域与听觉和前额叶皮层有强烈的连接。因此，个体的非语音听觉技能和左丘脑灰质体积可以预测听众适应退化语音的速度。
