Burton Harold, Reeder Ruth M, Holden Tim, Agato Alvin, Firszt Jill B
Department of Neuroscience, Washington University School of Medicine, Saint Louis, MO, United States.
Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, Saint Louis, MO, United States.
Front Neurosci. 2021 Apr 7;15:618326. doi: 10.3389/fnins.2021.618326. eCollection 2021.
Those with profound sensorineural hearing loss from single sided deafness (SSD) generally experience greater cognitive effort and fatigue in adverse sound environments. We studied cases with right ear, SSD compared to normal hearing (NH) individuals. SSD cases were significantly less correct in naming last words in spectrally degraded 8- and 16-band vocoded sentences, despite high semantic predictability. Group differences were not significant for less intelligible 4-band sentences, irrespective of predictability. SSD also had diminished BOLD percent signal changes to these same sentences in left hemisphere (LH) cortical regions of early auditory, association auditory, inferior frontal, premotor, inferior parietal, dorsolateral prefrontal, posterior cingulate, temporal-parietal-occipital junction, and posterior opercular. Cortical regions with lower amplitude responses in SSD than NH were mostly components of a LH language network, previously noted as concerned with speech recognition. Recorded BOLD signal magnitudes were averages from all vertices within predefined parcels from these cortex regions. Parcels from different regions in SSD showed significantly larger signal magnitudes to sentences of greater intelligibility (e.g., 8- or 16- vs. 4-band) in all except early auditory and posterior cingulate cortex. Significantly lower response magnitudes occurred in SSD than NH in regions prior studies found responsible for phonetics and phonology of speech, cognitive extraction of meaning, controlled retrieval of word meaning, and semantics. The findings suggested reduced activation of a LH fronto-temporo-parietal network in SSD contributed to difficulty processing speech for word meaning and sentence semantics. Effortful listening experienced by SSD might reflect diminished activation to degraded speech in the affected LH language network parcels. SSD showed no compensatory activity in matched right hemisphere parcels.
单侧耳聋（SSD）导致严重感音神经性听力损失的患者在不利的声音环境中通常会经历更大的认知努力和疲劳。我们研究了右耳SSD患者与正常听力（NH）个体的情况。尽管语义可预测性较高，但在频谱退化的8带和16带声码器句子中，SSD患者说出最后一个单词的正确率明显较低。对于可懂度较低的4带句子，无论可预测性如何，组间差异均不显著。SSD患者在早期听觉、听觉联合、额下回、运动前区、顶下小叶、背外侧前额叶、后扣带回、颞顶枕交界和后岛盖的左半球（LH）皮质区域，对这些相同句子的血氧水平依赖（BOLD）信号变化百分比也有所减少。与NH相比，SSD中振幅反应较低的皮质区域大多是LH语言网络的组成部分，此前已被指出与语音识别有关。记录的BOLD信号强度是这些皮质区域预定义脑区内所有顶点的平均值。除早期听觉和后扣带回皮质外，SSD不同区域的脑区对可懂度较高的句子（如8带或16带与4带）显示出明显更大的信号强度。在先前研究发现负责语音的语音学和音系学、意义的认知提取、单词意义的受控检索和语义学的区域中（与NH相比），SSD患者的反应强度明显更低。研究结果表明，SSD患者LH额颞顶网络的激活减少，导致处理单词意义和句子语义的语音困难。SSD患者经历的费力听力可能反映了受影响的LH语言网络脑区对退化语音的激活减少。SSD在匹配的右半球脑区中未显示出代偿性活动。
