Introduction: Numerous experimental and clinical studies have suggested a critical or sensitive period in which the auditory pathway develops its greatest potential in terms of plasticity and learning. Early cochlear implantation performed in prelingual deaf children in this period provides a better prognosis for language acquisition. The aim of this study is to show the importance of cochlear implantation before this critical period ends.
Methods: We conducted an observational, longitudinal, retrospective study of 57 children suffering profound prelingual bilateral sensorineural hearing loss who had received Advanced Bionics implants at our ENT department between June, 1998, and November, 2006. Data on their audiometric thresholds, the disyllabic word test adapted to children, open-set sentences recognition test and the Nottingham scale were analyzed.
Results: The analysis of audiometric thresholds showed no differences between children receiving the implants at different ages. However, statistically significant differences (p<0.05) were found in speech tests between groups of children receiving the implants before and after 4 years of age.
Conclusions: Our results are in line with other publications showing differences in auditory performance when comparing children with early implants versus children receiving the implants at a later age. We found the greatest differences at 4 years of age. Nevertheless, these findings should not exclude children over this age from implantation.