The relationship of inter-implant time and hearing outcomes for bilateral cochlear implants

Purpose: Determine the relationship between time elapsed between sequential bilateral cochlear implantation (BiCI) and speech intelligibility scores in post-lingually deafened adults. Materials and methods: Retrospective review of post-lingually deafened adults who received bilateral cochlear implants from January 1, 2011 to January 1, 2018 at an ambulatory tertiary referral center. Results: 113 patients (226 cochlear implants) were initially reviewed, with 56 patients (112 implants) being included in the final analysis. Median inter-implant interval was 187.5 days (IQ range 54.25-346.5). Maximum interval was 1787 days. Mean age at first implant was 60.66 +/- 13.37. Bilateral AzBio score in quiet and interimplant interval showed no significant correlation (r = 0.034, p = 0.815). There was no significant difference in mean bilateral AzBio scores in quiet between the simultaneous and sequential implantation groups (p = 0.22). Similar non-significant results were seen when examining the correlation between AzBio Difference and interimplant interval (r = -0.07, p = 0.66). No significant result between mean AzBio Difference of simultaneous and sequential implant recipients was found (p = 0.06). Conclusions: For the inter-implant intervals examined, there seems to be no significant decline in speech intelligibility scores for patients receiving sequential bilateral cochlear implants compared to simultaneously implanted patients. There was no significant correlation noted between increasing inter-implant intervals and speech intelligibility scores.