Background/Objectives: Early pediatric cochlear implantation positively impacts early language outcomes. The Teenager and Young Adults Cochlear Implant (TAYACI) study investigates the long-term outcomes of early implantation and factors influencing variability among cochlear implant (CI) users. This article outlines participants’ background, early language outcomes, and multidisciplinary study protocol. Methods and Materials: Individuals aged 12–22 received CIs before 30 months of age, followed-up at the same hearing implant center, and adhered to a standard school curriculum were invited to participate. Out of 109 eligible CI users, 50 participated; 46 agreed to undergo clinical assessments, while four completed questionnaires only. Results: The mean age at the first CI was 15.63 months (SD = 6.0). All but one communicated with spoken language(s). Participants attended mainstream schools and had highly educated parents. Over half (56%) had received Auditory Verbal Therapy in early childhood. Earlier implantation correlated with better language understanding one year post-CI. Conclusions: Earlier implantation was associated with better early language outcomes, with parental education level and early family-centered intervention likely contributing. Future sub-studies will investigate multidisciplinary long-term effects of pediatric cochlear implantation in adolescents.

Purpose: There is solid evidence that an early age at cochlear implantation, which reduces the period of auditory deprivation, positively impacts early spoken language development. However, there is an urgent need for more research to understand the long-term effects of early implantation on higher linguistic skills, such as metaphor comprehension. In this study, we explored metaphor comprehension in Swedish-speaking adolescents and young adults with cochlear implant (CI), compared to that of typically hearing peers, as well as its relationship with the age at first CI. Method: The participants consisted of 39 individuals who received CI before 30 months of age ( M _age = 16.9 years, mean age at implant = 15.7 months) and a group of 27 individuals with typical hearing ( M _age = 14.9 years). To assess metaphor comprehension, we developed a multiple-choice task that was administrated verbally. Standardized tests were used to evaluate vocabulary, reading skills, and nonverbal cognitive skills. Results: No significant differences were found in metaphor comprehension or other linguistic or cognitive skills between individuals with CI and the typically hearing peers. Further analysis indicated a moderate negative correlation between metaphor comprehension and age at implantation and other linguistic skills. Conclusions: Early-implanted children develop metaphor comprehension comparable to their typically hearing peers, with earlier age at implantation being associated with better metaphor comprehension in adolescence. However, age at implantation only partially explains the variation in metaphor comprehension abilities. Further research is needed to identify other factors that influence the development of metaphor comprehension in individuals with CI.

Purpose: The long-term effects of early cochlear implantation (CI) on higher- level language and cognitive abilities in adolescence are not well understood. This thesis examined whether adolescents and young adults with early CI show language and cognitive skills comparable to peers with typical hearing (TH), focusing on executive functions, word fluency, and metaphor comprehension, and explored the influence of age at implantation.Methods: Participants included 43 adolescents and young adults with cochlear implants (mean age 16.9 years, mean implantation age 15.6 months) and 27 peers with typical hearing (mean age 14.9 years). Cognitive and language abilities were assessed using standardized tests and experimental tasks. Executive functions and communicative skills were also evaluated via self- and parent-report questionnaires. Metaphor comprehension was assessed with a newly developed multiple-choice task. Word fluency tasks were used to measure semantic and phonological retrieval strategies. For the CI group, longitudinal vocabulary and word fluency data (ages 5-15) were obtained from medical records and analyzed using linear mixed models to explore the effects of age and age at implantation.Results: Participants with CI had significantly lower phonological working memory compared to peers with TH but performed similarly on all other measures. Earlier age at implantation was moderately associated with better phonological working memory and metaphor comprehension. Additionally, later- implanted participants relied more on semantic clustering strategies during word retrieval tasks. Associations between both executive functions and vocabulary measures, as well as between metaphor comprehension and relevant control variables, were less widespread in the CI group.Conclusions: Early-implanted adolescents and young adults show cognitive and language outcomes similar to peers with typical hearing. Early auditory access supports higher-level skills, including metaphor comprehension and phonological working memory. Compensatory strategies may support language processing in individuals with cochlear implants, though further research is needed to understand these mechanisms.List of scientific papersI. Löfkvist U, Dahlby-Skoog M, Persson A, Asp F, Verrecchia L, Gripenberg S, Karpeta N, Eklöf M, Karltorp E. Teenagers and Young Adults with Cochlear Implants: A Multidisciplinary Follow-Up Study Approach and Baseline Characteristics. Audiol Res. 2025 Feb 12;15(1):16. https://doi.org/10.3390/audiolres15010016II. Dahlby-Skoog M, Kalandadze T, Karltorp E, Lyxell B, Löfkvist U. Hearing Early Opens More Doors: Long-Term Effects of Age at Implantation on Metaphor Comprehension in Adolescents and Young Adults with Cochlear Implants. J Speech Lang Hear Res. 2025 Mar 5;68(3):1105-1125. https://doi.org/10.1044/2024_jslhr-24-00480III. Early Cochlear Implantation Supports Phonological Working Memory in Adolescents and Young Adults with Otherwise Typical Executive Functions. [Manuscript]IV. Lexical Retrieval Strategies and Vocabulary Development in Adolescents with Cochlear Implants. [Manuscript]

Background/Objectives: Early pediatric cochlear implantation positively impacts early language outcomes. The Teenager and Young Adults Cochlear Implant (TAYACI) study investigates long-term outcomes of early implantation and factors influencing variability among cochlear implant (CI) users. This article outlines participants’ background, early language outcomes, and multidisciplinary study protocol. Methods and Materials: Individuals aged 12-22 received CIs before 30 months of age, followed-up at the same hearing implant center, and adhered to a standard school curriculum were invited to participate. Out of 109 eligible CI users, 50 participated; 46 agreed to undergo clinical assessments, while four completed questionnaires only. Results: The mean age at 1st CI was 15.63 months (SD=6.0). All but one communicated with spoken language(s). Participants attended mainstream schools and had highly educated parents. Over half (56%) had received Auditory Verbal Therapy in early childhood. Earlier implantation correlated with better language understanding one year post-CI. Conclusions: Earlier implantation was associated with better early language outcomes, with parental education level and early family-centered intervention likely contributing. Future Sub-Studies will investigate multidisciplinary long-term effects of pediatric cochlear implantation in adolescents.

Purpose: The long-term effects of early cochlear implantation (CI) on higher- level language and cognitive abilities in adolescence are not well understood. This thesis examined whether adolescents and young adults with early CI show language and cognitive skills comparable to peers with typical hearing (TH), focusing on executive functions, word fluency, and metaphor comprehension, and explored the influence of age at implantation.Methods: Participants included 43 adolescents and young adults with cochlear implants (mean age 16.9 years, mean implantation age 15.6 months) and 27 peers with typical hearing (mean age 14.9 years). Cognitive and language abilities were assessed using standardized tests and experimental tasks. Executive functions and communicative skills were also evaluated via self- and parent-report questionnaires. Metaphor comprehension was assessed with a newly developed multiple-choice task. Word fluency tasks were used to measure semantic and phonological retrieval strategies. For the CI group, longitudinal vocabulary and word fluency data (ages 5-15) were obtained from medical records and analyzed using linear mixed models to explore the effects of age and age at implantation.Results: Participants with CI had significantly lower phonological working memory compared to peers with TH but performed similarly on all other measures. Earlier age at implantation was moderately associated with better phonological working memory and metaphor comprehension. Additionally, later- implanted participants relied more on semantic clustering strategies during word retrieval tasks. Associations between both executive functions and vocabulary measures, as well as between metaphor comprehension and relevant control variables, were less widespread in the CI group.Conclusions: Early-implanted adolescents and young adults show cognitive and language outcomes similar to peers with typical hearing. Early auditory access supports higher-level skills, including metaphor comprehension and phonological working memory. Compensatory strategies may support language processing in individuals with cochlear implants, though further research is needed to understand these mechanisms.List of scientific papersI. Löfkvist U, Dahlby-Skoog M, Persson A, Asp F, Verrecchia L, Gripenberg S, Karpeta N, Eklöf M, Karltorp E. Teenagers and Young Adults with Cochlear Implants: A Multidisciplinary Follow-Up Study Approach and Baseline Characteristics. Audiol Res. 2025 Feb 12;15(1):16. https://doi.org/10.3390/audiolres15010016II. Dahlby-Skoog M, Kalandadze T, Karltorp E, Lyxell B, Löfkvist U. Hearing Early Opens More Doors: Long-Term Effects of Age at Implantation on Metaphor Comprehension in Adolescents and Young Adults with Cochlear Implants. J Speech Lang Hear Res. 2025 Mar 5;68(3):1105-1125. https://doi.org/10.1044/2024_jslhr-24-00480III. Early Cochlear Implantation Supports Phonological Working Memory in Adolescents and Young Adults with Otherwise Typical Executive Functions. [Manuscript]IV. Lexical Retrieval Strategies and Vocabulary Development in Adolescents with Cochlear Implants. [Manuscript]