Single-channel in-Ear-EEG predicts the focus of auditory attention to concurrent tone streams and mixed speech
Conventional, multi-channel scalp electroencephalography (EEG) allows the identification of the attended speaker in concurrent-listening (\"cocktail party\") scenarios. This implies that EEG might provide valuable information to complement hearing aids with some form of EEG and to install a level of neuro-feedback. To investigate whether a listeners attentional focus can be predicted from single-channel hearing-aid-compatible EEG configurations, we recorded EEG from three electrodes inside the ear canal (\"in-Ear-EEG\") and additionally from 64 electrodes on the scalp. In two different, concurrent listening tasks, participants (n = 7) were fitted with individualized in-Ear-EEG pieces and were either asked to attend to one of two dichotically-presented, concurrent tone streams or to one of two diotically-presented, concurrent audiobooks. A forward encoding model was trained to predict the EEG response at single EEG channels. We found that all individual participants attentional focus could be predicted from single-channel EEG response recorded from short-distance configurations consisting only of a single in-Ear-EEG electrode and an adjacent scalp-EEG electrode. The responses to attended and ignored stimuli reveal differences consistent across subjects. In sum, our findings show that the EEG response from a single-channel, hearing-aid-compatible configuration provides valuable information to identify a listeners focus of attention.