Establishing a Mental Lexicon with Cochlear Implants

In this research project we explore the implications of acquiring language when relying mainly or exclusively on input from a cochlear implant (CI), a device providing auditory input to otherwise deaf individuals. We focus on the time course of semantic learning in children within the second year of implant use; a period that equals the auditory age of normal hearing children during which vocabulary emerges and extends dramatically. 32 young bilaterally implanted children saw pictures paired with either matching or non-matching auditory words. Their electroencephalographic responses were recorded after 12, 18 and 24 months of implant use, revealing a large dichotomy: Some children failed to show semantic processing throughout their second year of CI use, which fell in line with their poor language outcomes. The majority of children, though, demonstrated semantic processing in form of the so-called N400 effect already after 12 months of implant use, even when their language experience relied exclusively on the implant. This is slightly earlier than observed for normal hearing children of the same auditory age, suggesting that more mature cognitive faculties at the beginning of language acquisition lead to faster semantic learning.

Event-related potentials at electrode Pz for CI children at 12, 18 and 24 months after implantation. The second row represents the subgroup of congenitally deaf children. Time windows with a significant difference between the two conditions (* correlates to p smaller 0.05) are marked by a grey area and an asterisk. Figure from Niki K. Vavatzanidis et al. (https://doi.org/10.1038/s41598-017-18852-3) licensed under CC BY 4.0

Event-related potentials within the different age groups sorted according to low/norm/high language test performance at 24 months after implantation at electrode Pz. CI children of the norm and high group show clear N400 effects even at 12 months after implantation, which is a year earlier than the language test can be performed and 2 months earlier than controls show the effect (based on hearing age). By contrast, the low performance group does not show a N400 effect at any testing point. Figure from Niki K. Vavatzanidis et al. (https://doi.org/10.1038/s41598-017-18852-3) licensed under CC BY 4.0

 Publications

• Vavatzanidis, N.K., Mürbe, D., Friederici, A.D., & Hahne, A. (2018). Establishing a mental lexicon with cochlear implants: an ERP study with young children. Scientific Reports, 8:910. https://doi.org/10.1038/s41598-017-18852-3

Funding

• Marga und Walter Boll-Stiftung
• Max Planck Society

Contact

• Niki Vavatzanidis, email
• Anja Hahne, email