Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Psychiatry and Psychotherapy, Charitéplatz 1, 10117 Berlin, Germany.
Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Psychiatry and Psychotherapy, Charitéplatz 1, 10117 Berlin, Germany.
Neuroimage Clin. 2022;33:102909. doi: 10.1016/j.nicl.2021.102909. Epub 2021 Dec 8.
People with Schizophrenia (SZ) show deficits in auditory and audiovisual speech recognition. It is possible that these deficits are related to aberrant early sensory processing, combined with an impaired ability to utilize visual cues to improve speech recognition. In this electroencephalography study we tested this by having SZ and healthy controls (HC) identify different unisensory auditory and bisensory audiovisual syllables at different auditory noise levels.
SZ (N = 24) and HC (N = 21) identified one of three different syllables (/da/, /ga/, /ta/) at three different noise levels (no, low, high). Half the trials were unisensory auditory and the other half provided additional visual input of moving lips. Task-evoked mediofrontal N1 and P2 brain potentials triggered to the onset of the auditory syllables were derived and related to behavioral performance.
In comparison to HC, SZ showed speech recognition deficits for unisensory and bisensory stimuli. These deficits were primarily found in the no noise condition. Paralleling these observations, reduced N1 amplitudes to unisensory and bisensory stimuli in SZ were found in the no noise condition. In HC the N1 amplitudes were positively related to the speech recognition performance, whereas no such relationships were found in SZ. Moreover, no group differences in multisensory speech recognition benefits and N1 suppression effects for bisensory stimuli were observed.
Our study suggests that reduced N1 amplitudes reflect early auditory and audiovisual speech processing deficits in SZ. The findings that the amplitude effects were confined to salient speech stimuli and the attenuated relationship with behavioral performance in patients compared to HC, indicates a diminished decoding of the auditory speech signals in SZs. Our study also revealed relatively intact multisensory benefits in SZs, which implies that the observed auditory and audiovisual speech recognition deficits were primarily related to aberrant processing of the auditory syllables.
精神分裂症（SZ）患者在听觉和视听语音识别方面存在缺陷。这些缺陷可能与异常的早期感觉处理有关，同时也可能与利用视觉线索改善语音识别的能力受损有关。在这项脑电图研究中，我们通过让 SZ 和健康对照组（HC）在不同的听觉噪声水平下识别不同的单感觉听觉和双感觉视听音节，来测试这一点。
SZ（N=24）和 HC（N=21）在三个不同的噪声水平（无、低、高）下识别三个不同音节（/da/、/ga/、/ta/）中的一个。一半的试验是单感觉听觉，另一半提供了移动嘴唇的额外视觉输入。从听觉音节开始引发的任务诱发中前额 N1 和 P2 脑电位与行为表现相关。
与 HC 相比，SZ 在单感觉和双感觉刺激下的语音识别存在缺陷。这些缺陷主要出现在无噪声条件下。与这些观察结果平行，在 SZ 中，无噪声条件下，单感觉和双感觉刺激的 N1 振幅减小。在 HC 中，N1 振幅与语音识别性能呈正相关，而在 SZ 中则没有这种关系。此外，对于双感觉刺激的多感觉语音识别增益和 N1 抑制效应，没有观察到组间差异。
我们的研究表明，N1 振幅的降低反映了 SZ 中早期听觉和视听语音处理的缺陷。这些发现表明，在患者中，振幅效应仅限于明显的语音刺激，并且与行为表现的关系减弱，这表明 SZ 中听觉语音信号的解码能力降低。我们的研究还揭示了 SZ 中相对完整的多感觉益处，这意味着观察到的听觉和视听语音识别缺陷主要与听觉音节的异常处理有关。
