Isolated Second Implant Adaptation Period in Sequential Cochlear Implantation in Adults

To determine if depriving the use of the first cochlear implant (CI1) impacts adaptation to a sequential implant (CI2).Prospective cohort.Academic center.Sixteen unilateral cochlear implant recipients undergoing contralateral implantation (sequential bilateral) were matched according to age, etiology, duration of deafness, device age, and delay between implants.During a 4-week adaptation period after CI2 activation, patients underwent deprivation of CI1 or were permitted continued use of it.Speech perception scores and subjective quality of life outcomes before CI2 and at 1, 3, 6, and 12-months following activation.Maximal CI2 speech perception scores in quiet were achieved by 1-month postactivation for the "deprivation" group (71.3% for hearing in noise test [HINT], p = 0.767 for change beyond 1-mo) compared with 6-months for the "continued use" group (67.9% for HINT, p = 0.064 for change beyond 6-mo). The "deprivation" group experienced a temporary drop in CI1 scores (67.9% for HINT in quiet at 1-mo versus 78.4% pre-CI2, p = 0.009) recovering to 77.3% by 3-months; unchanged from baseline levels (p = 1.0). A binaural advantage over the better hearing ear was present for HINT sentences with noise (72.4% versus 58.8% for "deprivation", p = 0.001; 71.5% versus 52.7% for "continued use," p = 0.01). Missing data precluded a meaningful analysis of subjective quality of life outcome scales.Bilateral cochlear implantation improves speech perception compared with one implant. A period of deprivation from CI1 shortens time to maximum speech perception by CI2 without long-term consequences on the performance of CI1.