The neural processing mode and development of emotional prosody in children with cochlear implants

Prelingually deaf children with cochlear implants (CIs) receive a degraded representation of pitch and spectral cues that are critical for decoding emotional prosody. The early cortical processing modes and developmental trajectories of vocal emotion in CI children remain unclear.

Nineteen prelingually bilaterally deaf children with unilateral cochlear implants were followed longitudinally at three post-activation windows. At each visit, children were passively presented with pseudo-sentences spoken with angry, happy, fearful, or neutral prosody while cortical activity was recorded using functional near-infrared spectroscopy (fNIRS). Auditory-speech outcome scores were obtained from standardized parent-reported measures. Oxyhemoglobin (HbO) changes were analyzed with factors Time, Emotion, and their interaction, followed by targeted post hoc tests. Slope-based behavior-neural coupling analyses linking cortical developmental trajectories to composite auditory-speech scores.

Behaviorally, auditory-speech outcomes improved robustly and monotonically across visits. Neurally, emotion-specific Time × Emotion effects were confined in right primary and association auditory cortex, where trajectories for neutral, happy and fearful prosodies diverged. Additional longitudinal changes in premotor and temporo-parietal regions revealed distinct, partially lateralised profiles for each emotion. Crucially, steeper decreases in neutral-evoked activity in right supramarginal gyrus, together with similar patterns in left angular, right premotor and fusiform regions, predicted faster auditory-speech gains.

Early after CI activation, children show emotion- and region-specific reorganization of prosodic processing, and the developmental trajectory of neutral prosody responses in temporo-parietal and auditory regions closely tracks recovery of auditory-speech abilities, suggesting a candidate neural marker of early outcome.