Objectives: First, to document a broad range of functional outcomes of bilateral implantation for young children through young adults at a postoperative point at which stable outcomes could be expected. Second, to evaluate the relationship between functional outcomes and age at bilateral implantation and time between implants.
Design: A study-specific questionnaire was administered to parents in an interview 3.5 years or more after sequential (n = 50) or simultaneous (n = 7) implants were received by their child. Median age at bilateral implantation was 4.1 years (range 0.7 to 19.8) and time between implants was 2.7 years (range 0.0 to 16.7).
Results: On the basis of parent report, 72% of the sequentially implanted children and young adults found it easy/only "a bit difficult" to adapt to the second implant, and were "happily wearing both implants together most of the time" by 6 months or before; 26% had not adapted, with both implants not worn most of the time or worn as a parental requirement. Seventy-two percent of sequentially implanted children and young adults had a positive attitude toward the second implant, including 9 whose early postoperative attitude was negative or neutral. The majority of children and young adults preferred bilateral implants (70%) and used the two full time (72%), while around half demonstrated similar performance with each implant alone. The proportion of nonusers or very minimal users of the second implant was just 9%. Eighty-eight percent of parents reported superior performance with bilateral versus a unilateral implant (n = 40), or that only bilateral implants were worn (n = 10) so performance could not be compared. The most commonly identified areas of superiority were localization, less need for repetition, and increased responsiveness. In balancing risks and costs with benefits, most parents (86%) considered the second implant worthwhile. Regarding the relationship between outcomes and demographic factors, the group achieving similar performance with each implant alone was younger at bilateral implantation and had less time between implants, and the group bilaterally implanted before 3.5 years of age (who also had less than 2 years between implants) had a higher proportion of positive outcomes on all functional outcome measures.
Conclusion: Overall, the results indicate primarily positive functional outcomes for children and young adults receiving bilateral implants at all ages, including when the delay between implants is long. The results are important for evidence-based preoperative counseling, which helps families to make informed decisions and develop appropriate expectations. The results are also important for the development of clinical management practices that support and encourage the minority of recipients who have difficulty adapting to bilateral implants or achieving full-time use.