How Hearing Loss and Cochlear Implantation Affect Verbal Working Memory: Evidence From Adolescents

Area of Science:

• Neuroscience
• Developmental Psychology
• Audiology

Background:

• Verbal working memory is crucial for academic success.
• Children with hearing loss often exhibit poorer verbal working memory compared to normal-hearing peers, even with interventions.
• This deficit persists into adolescence, impacting learning.

Purpose of the Study:

• To examine the stability of verbal working memory in middle childhood.
• To compare working memory in adolescents with normal hearing (NH) versus cochlear implants (CIs).
• To investigate if signal enhancement can improve verbal working memory and test hypotheses explaining deficits in children with hearing loss.

Main Methods:

• Assessed working memory in 55 NH and 52 CI adolescents (14-year-olds) using immediate serial recall tasks.
• Utilized verbal (rhyming/non-rhyming words) and nonverbal (spatial) stimuli.
• Analyzed effects of signal enhancement (audiovisual, indexical) and phonological processing abilities.

Main Results:

• Verbal working memory was stable across middle childhood.
• Adolescents with CIs showed poorer verbal recall than NH peers, but performed similarly on nonverbal tasks.
• Signal enhancement did not improve verbal recall; phonological sensitivity deficits largely explained the group differences.

Conclusions:

• The central executive component of working memory is unaffected by hearing loss or cochlear implantation.
• Phonological deficits in adolescents with CIs impair verbal memory storage representation.
• Augmenting the auditory signal does not mitigate these phonological-related working memory deficits.