Nice article that bears out predictions made by Peelle & Sommers (2015).
We demonstrate that the cortical representation of the speech envelope is enhanced by the presentation of congruent audiovisual speech in noise-free conditions. Furthermore, we show that this is likely attributable to the contribution of neural generators that are not particularly active during unimodal stimulation and that it is most prominent at the temporal scale corresponding to syllabic rate (2–6 Hz). Finally, our data suggest that neural entrainment to the speech envelope is inhibited when the auditory and visual streams are incongruent both temporally and contextually.
