Cortical responses correlate with speech performance in pre-lingually deaf cochlear implant children

Area of Science:

• Neuroscience
• Audiology
• Developmental Psychology

Background:

• Cochlear implantation (CI) is a key intervention for severe-to-profound sensorineural hearing loss in children.
• Significant variability exists in speech outcomes among pediatric CI recipients.
• Understanding the neural basis of this variability is crucial for optimizing CI efficacy.

Purpose of the Study:

• To investigate the cortical correlates of speech outcome variability in pre-lingually deaf children with cochlear implants.
• To utilize functional near-infrared spectroscopy (fNIRS) to examine brain activity during speech processing.

Main Methods:

• fNIRS was used to measure cortical activity in 38 pre-lingually deaf children with CI and 36 normally hearing (NH) children.
• Participants processed visual speech and auditory speech in quiet and noise.
• Regions of interest included fronto-temporal-parietal language networks, specifically the superior temporal gyrus, inferior frontal gyrus, and inferior parietal lobes.

Main Results:

• Cortical responses in the superior temporal gyrus correlated with auditory speech perception scores, with greater cross-modal reorganization linked to better CI outcomes.
• CI users, especially those with good speech perception, exhibited increased left inferior frontal gyrus activation compared to NH controls across all speech stimuli.

Conclusions:

• Cross-modal visual speech processing in the auditory cortex may explain variable CI performance in pre-lingually deaf children.
• Left inferior frontal gyrus activation could serve as a neural marker for effortful listening in CI users.
• These findings support the prediction and assessment of CI outcomes in clinical settings.