Fig. 4.

ERP results on the source level. A) N1 and P2 source activity for CI users (red), CI-SSD users (green) and NH listeners (blue) separately for each ROI and each hemisphere with standard error (standard error shading was capped at zero). The source activity is displayed as absolute values with arbitrary units based on the normalisation within Brainstorm's dSPM algorithm. The grey shaded areas mark the N1 (light grey) and the P2 (dark grey) time windows. The boxes depict the location of the defined ROIs, with auditory ROIs in blue and visual ROIs in yellow. B) Group effect of the N1 peak mean in the visual cortex: both CI-CHD and CI-SSD users show more activity in the visual cortex compared to NH listeners, regardless of condition. C) Condition effect of the N1 peak mean in the auditory cortex: there is a significantly reduced auditory-cortex activation for AV-V compared to A, indicating multisensory interactions in all groups. D) N1 latency effect in the auditory cortex: Both CI and CI-SSD users show a prolonged N1 latency compared to NH listeners in the auditory cortex, regardless of the condition. This suggests a delayed auditory-cortex activation in CI users, independent of the hearing threshold in the contralateral ear. E) P2 condition effect in the visual cortex: there is a significantly reduced visual-cortex activation for AV-V compared to A, pointing towards multisensory interactions in all groups. Significant differences are indicated (* $p<0.05$, ** $p<0.01$, *** $p<0.001$). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)