There is a tendency for children undergoing sequential cochlear implant after a long period of unilateral implant use to have a smaller dynamic range in their second implant compared to their first implant. This study aimed to investigate if balancing the dynamic ranges between the two implants influenced functional outcomes in sequentially implanted children. Nineteen participants with long inter-implant time delays were randomly assigned to a study group or a control group. Children in the study group received progressive minimal changes to both first and second implants over a period of nine months to achieve balanced dynamic ranges, while the children in the control group received only changes to their sequential implant. Functional outcomes were collected 24-months after sequential implantation and consisted of speech discrimination scores, spatial localisation, device use and quality of life measures. Results show that spatial discrimination skills improved over time for both groups of children; however children in the study group had smaller localisation errors compared with the children in the control group. No other differences between the two groups were observed. Balanced dynamic ranges in sequentially implanted children can contribute to better performance, particularly in spatial discrimination tasks that rely in inter-aural level differences.
Keywords: Cochlear implant; Dynamic Range (DR); Inter implant delay; Sequential programming; Spatial discrimination.