Neural correlates of visual stimulus encoding and verbal working memory differ between cochlear implant users and...

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Cognitive Neuroscience

Background:

• Individuals with severe-to-profound hearing loss using cochlear implants (CIs) often struggle with understanding speech in noisy environments.
• This difficulty is potentially linked to individual variations in cognitive functions like verbal working memory and sensory plasticity.
• The precise neural mechanisms underlying these relationships remain unclear.

Purpose of the Study:

• To investigate the neural correlates of visual verbal working memory and sensory plasticity in cochlear implant (CI) users.
• To compare these neural correlates with those of age-matched normal-hearing (NH) controls.

Main Methods:

• Utilized high-density electroencephalogram (EEG) to record brain activity.
• Employed a modified Sternberg visual working memory task involving visual presentation and delayed recall of letters and numbers.
• Included 14 CI users and age-matched NH controls.

Main Results:

• Behavioral working memory performance was comparable between CI users and NH controls.
• CI users exhibited more pronounced neural activity during visual stimulus encoding, including enhanced visual-evoked activity and altered neural oscillations.
• During memory retention, CI users showed weaker neural oscillations and reduced frontotemporal connectivity compared to NH controls.

Conclusions:

• Neural processing differences in CI users during visual working memory tasks are evident.
• These findings suggest that cross-modal and intramodal plasticity play a role in how CI users process visual information.
• Understanding these neural adaptations is crucial for addressing challenges faced by CI users in complex listening environments.