Simultaneous versus sequential bilateral implantation in young children: Effects on central auditory system development and plasticity

The aim of this study was to determine whether children who received early, simultaneous, bilateral cochlear implants showed more rapid development of the central auditory pathways compared to children who received early, sequential, bilateral implants. In 20 children, over the first 15 months following bilateral implantation, we assessed longitudinal changes in the morphology and latency of the P1 cortical response, which is generated within the auditory cortex. Our results showed that by 3.5 months post-implantation, mean P1 latencies for both groups of children were within normal limits. Overall, the developmental trajectory of the P1 response did not differ significantly for the two groups over the 15-month period. Our results suggest that bilateral implantation, whether sequential or simultaneous, occurring within a sensitive period of 3.5 years, takes advantage of the high degree of plasticity in the developing central auditory nervous system.