Clinical NeuroscienceA spatial approach of magnitude-squared coherence applied to selective attention detection

•We acquired the EEG during an auditory selective attention protocol.•We developed a new index to detect the focus of auditory attention.•This index takes into account both the electrode location and coherence value.•The index seemed to be suitable for BCI applications.

BackgroundAuditory selective attention is the human ability of actively focusing in a certain sound stimulus while avoiding all other ones. This ability can be used, for example, in behavioral studies and brain-machine interface.New methodIn this work we developed an objective method - called Spatial Coherence - to detect the side where a subject is focusing attention to. This method takes into consideration the Magnitude Squared Coherence and the topographic distribution of responses among electroencephalogram electrodes. The individuals were stimulated with amplitude-modulated tones binaurally and were oriented to focus attention to only one of the stimuli.ResultsThe results indicate a contralateral modulation of ASSR in the attention condition and are in agreement with prior studies. Furthermore, the best combination of electrodes led to a hit rate of 82% for 5.03 commands per minute.Comparison with existing method(s)Using a similar paradigm, in a recent work, a maximum hit rate of 84.33% was achieved, but with a greater a classification time (20 s, i.e. 3 commands per minute).ConclusionsIt seems that Spatial Coherence is a useful technique for detecting focus of auditory selective attention.