Fiedler L, Obleser J, Lunner T, Graversen C
Annu Int Conf IEEE Eng Med Biol Soc. 2016 Aug;2016:5697-5700. doi: 10.1109/EMBC.2016.7592020.
Advances in brain-computer interface research have recently empowered the development of wearable sensors to record mobile electroencephalography (EEG) as an unobtrusive and easy-to-use alternative to conventional scalp EEG. One such mobile solution is to record EEG from the ear canal, which has been validated for auditory steady state responses and discrete event related potentials (ERPs). However, it is still under discussion where to place recording and reference electrodes to capture best responses to auditory stimuli. Furthermore, the technology has not yet been tested and validated for ecologically relevant auditory stimuli such as speech. In this study, Ear-EEG and conventional scalp EEG were recorded simultaneously in a discrete-tone as well as a continuous-speech design. The discrete stimuli were applied in a dichotic oddball paradigm, while continuous stimuli were presented diotically as two simultaneous talkers. Cross-correlation of stimulus envelope and Ear-EEG was assessed as a measure of ongoing neural tracking. The extracted ERPs from Ear-EEG revealed typical auditory components yet depended critically on the reference electrode chosen. Reliable neural-tracking responses were extracted from the Ear-EEG for both paradigms, albeit weaker in amplitude than from scalp EEG. In conclusion, this study shows the feasibility of extracting relevant neural features from ear-canal-recorded "Ear-EEG", which might augment future hearing technology.
脑机接口研究的进展最近推动了可穿戴传感器的发展，以记录移动脑电图（EEG），作为传统头皮脑电图的一种不引人注意且易于使用的替代方法。一种这样的移动解决方案是从耳道记录脑电图，这已在听觉稳态反应和离散事件相关电位（ERP）方面得到验证。然而，关于将记录电极和参考电极放置在何处以捕获对听觉刺激的最佳反应仍在讨论中。此外，该技术尚未针对语音等与生态相关的听觉刺激进行测试和验证。在本研究中，在离散音调以及连续语音设计中同时记录耳脑电图和传统头皮脑电图。离散刺激应用于双耳奇偶数范式，而连续刺激以两个同时说话者的方式双耳呈现。刺激包络与耳脑电图的互相关被评估为正在进行的神经跟踪的一种度量。从耳脑电图中提取的ERP显示出典型的听觉成分，但关键取决于所选择的参考电极。尽管幅度比头皮脑电图弱，但两种范式均从耳脑电图中提取到了可靠的神经跟踪反应。总之，本研究表明从耳道记录的“耳脑电图”中提取相关神经特征的可行性，这可能会促进未来听力技术的发展。
