Beyond Vocabulary Parity: Masked Weaknesses in Recalling Sentences and the Role of Working Memory in Children With Cochlear Implants

This cross-sectional study investigated the often-neglected complex language skills and working memory (WM) in early implanted school-aged children with cochlear implants (CI) and their typically developing (TD) peers. Thirty-four 8- to 12-year-old participants (12 with CI) were assessed on expressive vocabulary (EVoc), recalling sentences (RS), phonological WM (PWM) and general WM (GWM). Bayesian methods were used to examine group differences, relationships with implantation and hearing age, as well as the relationship between complex language and WM. While children with CI achieved parity with TD peers in EVoc and GWM, significant deficits persisted in RS and PWM. As supported by weak evidence, performance was more likely to be unrelated than related to implantation or hearing age, a pattern more consistent with a sensory-driven account of cognitive development than with the auditory scaffolding hypothesis. In children with CI, RS was more likely to correlate than not with both PWM and GWM, whereas the opposite pattern was observed for EVoc and both WM measures, albeit supported by weak evidence. This suggests that defining words may rely on crystallized knowledge, while RS places greater demands on real-time integration of multiple linguistic elements (e.g. phonological, lexical and morphosyntactic information). Clinically, vocabulary parity may therefore mask higher-order weaknesses, and RS could be a useful tool for more comprehensive assessment.