Two are better than one: Differences in cortical EEG patterns during auditory and visual verbal working memory...

Area of Science:

• Neuroscience
• Audiology
• Cognitive Psychology

Background:

• Cochlear implants (CIs) restore hearing in deaf children, but verbal working memory (VWM) varies significantly.
• Deficits in VWM, a key executive function, are noted in CI users, yet the underlying causes remain unclear.

Purpose of the Study:

• To investigate electroencephalographic (EEG) differences in auditory and visual VWM performance between children with unilateral CIs (UCIs), bilateral CIs (BCIs), and normal hearing (NH) peers.
• To identify EEG marker patterns associated with VWM performance across different difficulty levels and sensory modalities.

Main Methods:

• Participants (UCI, BCI, NH children) performed a three-level difficulty n-back task in auditory and visual modalities.
• EEG data were recorded to analyze brain activity patterns, focusing on theta and gamma frequency bands.

Main Results:

• UCIs exhibited frontal theta hypoactivation during complex auditory tasks, correlating with VWM performance, unlike NH peers and BCIs.
• UCIs showed reduced left hemispheric theta and gamma band activity compared to BCIs and NH peers.
• Gamma oscillations in the left hemisphere correlated with auditory task performance in NH and BCI groups.

Conclusions:

• Unilateral CI use appears insufficient for optimal auditory VWM in deaf children.
• Bilateral CI use may enable deaf children to achieve VWM performance comparable to NH children.
• EEG analysis shows promise for diagnosing and rehabilitating VWM deficits in deaf children.