Neural Correlates of Speech Comprehension in Normal Hearing Individuals and Cochlear Implant Users - An fNIRS Study...

This study investigates neural activity during a clinical hearing test transformed into a neuroimaging speech paradigm, focusing on individuals with cochlear implants (CIs) and normal hearing (NH) controls. Participants listened to sentences in quiet and noise conditions, and answered comprehension questions, while brain activation patterns were measured using functional near-infrared spectroscopy (fNIRS). NH participants exhibited effective strategies for speech comprehension in noise, with increased activity in left prefrontal regions. Good-performing CI users showed reduced accuracy and confidence, coupled with elevated listening effort in both conditions. Their brain activity in the bilateral temporal and left prefrontal regions were comparable to NH. Poor-performing CI users exhibited high effort and low accuracy in noise, with unclear brain activation patterns, suggesting cortical challenges in adapting to the auditory input provided by CIs.Clinical relevance- The study provides important insights into the compensatory strategies and cognitive demands of CI users during different hearing conditions. This contributes to our understanding of the neural aspects in speech processing for individuals with hearing loss and guide potential interventions and further improvement of devices to improve the auditory experience of CI users.