Cochlear implantation in adults with prelingual deafness: II. Underlying constraints that affect audiological outcomes

Objectives/Hypothesis: To examine the hypothesis that the newer generations of cochlear implants could provide considerable speech understanding to late-implanted, prelingually deaf adult patients. Study Design: Retrospective review. Methods: Speech perception scores of 103 patients with long-term pre-lingual deafness obtained from the recent clinical tri-als were compared with other previously published results. Results: Unlike patients receiving implants in early childhood, the audiologic performance of most patients with long-term prelingual deafness rapidly approached asymptotic levels within 1 year after im-plantation. Beginning at 3 months postimplantation, statistically significant improvement was noted in their speech perception scores compared with their preimplant levels. However, the average performance plateau achieved by this group of patients was signif-icantly below the levels published for postlingual pa-tients. No statistically significant differences were ob-served between the test scores at any testing interval among patients with different devices. Conclusions: Most patients with long-term prelingual deafness achieve their performance plateau within 1 year after implantation. The results suggest that patient char-acteristics, rather than device properties, are likely to be the major contributing factor responsible for the observed audiologic outcomes. Key Words: Cochlear implants, critical period, congenital deafness, long