Fig. 2. Model performance while listening to external speech.

a Correlation coefficients for every frequency band and their spatial distribution obtained from the spectrogram model. The correlation values were obtained for each electrode and averaged across the 5 folds within each participant, then averaged across participants. The top panel A shows the spatial distribution of the averaged correlation values, to better determine the regions where higher correlation is achieved. The distribution shown in the lower panel consists of those same values but presented in a violin plot, for an easier comparison across frequency bands. b Correlation distribution for left and right electrodes indicated in the topographic figure, for the models using spectrogram and envelope as input features. The electrodes were chosen as the 12 presenting higher correlation values in the frontal region for each hemisphere and a signed-rank Wilcoxon test was performed to compare the values obtained in each hemisphere (N = 12 independent samples). The correlation values for the spectrogram show a significant lateralization effect towards the left hemisphere, with a p-value of ~0.0005, whereas the envelope shows no significant difference (p-value ~ 0.38). Significance: n.s p-value > 0.05, *p-value < 0.001.