Figure 5.
Cortical lateralization for each peak of the cortical waveform was assessed across 63,646 peak dipoles using permutation testing to compare activation of the left and right hemispheres. Significant absolute differences in dipole for right – left hemisphere (voxel‐wise permutation, P < 0.05, corrected for 62 recording channels; Bonferroni correction P = 0.05/62 = 0.0008) are plotted on topographic plots for stimulation of the right ear in A. and the left ear in B. for adolescents with normal hearing; and the right‐experienced CI in C. and naïve‐left side in D. in the implant cohort. Auditory activity lateralized towards the right hemisphere in normal hearing individuals, particularly in response to left ear stimulation, as shown by the dark red hotspots indicating greater inter‐hemispheric dipole differences. A significant shift in lateralization towards the contralateral left auditory cortex was observed in CI users with stimulation of the experienced‐right side. Cortical asymmetries towards the auditory cortices in either hemisphere were not clear when stimulated from the naïve side. Lateralization of secondary sources in the left temporo‐parietal junction and right temporo‐frontal cortex was present for the experienced‐right side, with stronger activity underlying P 2. This activity was reversed on the naïve‐left side and occurred with increased dipole strength in the right parietal‐temporal‐occipital association areas and left temporo‐frontal cortex.