gms | German Medical Science

Introduction: In order to get a complete development of the central auditory system it is mandatory to have a proper stimulation of the ascending auditory pathway. The goal of this communication is to present our findings concerning an auditory critical period for a sequential implant procedure and study the benefits of such bilateral stimulation in children.

Material & Methods: From a population of 142 bilateral implanted children, we study 41 children sequentially implanted with a follow-up of 5 years at least. Mean age at the first implantation was 2.31 years (range 1–9 years) and at the second implantation 7.55 years (range 3–15 years). Open-set logoaudiometric testing has been used in different conditions for auditory evaluation.

Results: The separate analysis of both ears shows that discrimination of disyllable words was significantly lower in the second implanted ears at 1, 2, 3, 4 and 5 postoperative years. A negative correlation is found when the analysis compares discrimination level and the age at implantation of the first and second ear. The critical period for the second implanted ear was 10–12 years. Results show a binaural benefit with the use of both CI. These benefits were significant when the time of the first and second implantation was lower than 6 years.

Conclusions: In children considered for sequential implantation, an early second implantation procedure is advisable.