Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.
Department of Psychology, University of Western Ontario, London, ON, Canada.
Sci Rep. 2018 Jul 27;8(1):11345. doi: 10.1038/s41598-018-29598-x.
For many cochlear implant (CI) users, visual cues are vitally important for interpreting the impoverished auditory speech information that an implant conveys. Although the temporal relationship between auditory and visual stimuli is crucial for how this information is integrated, audiovisual temporal processing in CI users is poorly understood. In this study, we tested unisensory (auditory alone, visual alone) and multisensory (audiovisual) temporal processing in postlingually deafened CI users (n = 48) and normal-hearing controls (n = 54) using simultaneity judgment (SJ) and temporal order judgment (TOJ) tasks. We varied the timing onsets between the auditory and visual components of either a syllable/viseme or a simple flash/beep pairing, and participants indicated either which stimulus appeared first (TOJ) or if the pair occurred simultaneously (SJ). Results indicate that temporal binding windows-the interval within which stimuli are likely to be perceptually 'bound'-are not significantly different between groups for either speech or non-speech stimuli. However, the point of subjective simultaneity for speech was less visually leading in CI users, who interestingly, also had improved visual-only TOJ thresholds. Further signal detection analysis suggests that this SJ shift may be due to greater visual bias within the CI group, perhaps reflecting heightened attentional allocation to visual cues.
对于许多人工耳蜗（CI）使用者来说，视觉线索对于解释植入物传达的贫乏听觉言语信息至关重要。尽管听觉和视觉刺激之间的时间关系对于信息的整合至关重要，但 CI 用户的视听时间处理仍知之甚少。在这项研究中，我们使用同时性判断（SJ）和时间顺序判断（TOJ）任务，测试了后天失聪的 CI 用户（n=48）和正常听力对照者（n=54）的单感觉（听觉单独，视觉单独）和多感觉（视听）时间处理。我们改变了音节/视位或简单闪光/蜂鸣声对中听觉和视觉成分的时间起始，参与者指出哪个刺激先出现（TOJ）或对是否同时发生（SJ）做出指示。结果表明，对于语音或非语音刺激，时间绑定窗口（刺激在其中可能被感知为“绑定”的间隔）在组间没有显著差异。然而，语音的主观同时性点在 CI 用户中视觉上的领先程度较低，有趣的是，CI 用户的视觉单独 TOJ 阈值也有所提高。进一步的信号检测分析表明，SJ 变化可能是由于 CI 组内存在更大的视觉偏差，这可能反映了对视觉线索的注意力分配增加。
