Effect of age at cochlear implantation on open-set word recognition in Mandarin speaking deaf children

Objective: The purpose of this study was to determine whether age at cochlear implantation influences open-set speech perception in children after long-term use of the implant device. Method: Twenty-eight congenitally deafened children, receiving implants of Nucleus CI24M devices, were divided into two groups: (1) CI < 3: those who received implants before 3 years of age and (2) CI > 3: those who received implants after 3 years of age. We compared open-set speech perception in CI < 3 and CI > 3 after 4-5 years of device use. Speech perception tests were conducted using the Mandarin Lexical Neighborhood Test (M-LNT). Unpaired t-test was applied for statistical analysis, and p < 0.05 was considered significant. Results: In CI < 3, the average of percent correct was 80.0 ± 8.8 and 70.5 ± 9.2% on, respectively, the easy and hard versions of the M-LNT. By contrast, in CI > 3, the average percent correct was 62.5 ± 19.9 and 59.1 ± 15.2%, respectively. Regardless of the M-LNT version used, CI < 3 performed significantly better than CI > 3 (easy, p = 0.005 versus hard, p = 0.022). Conclusion: The present investigation demonstrated that age at implantation influences open-set speech perception of cochlear implanted children 4-5 years after device connection. Implantation before 3 years of age promotes the development of open-set speech perception abilities in congenitally deafened children.