Comparing the performance plateau in adult cochlear implant patients using HINT and AzBio

OBJECTIVE: This study aims to characterize the performance plateau in adult cochlear implant recipients after the initial postimplantation increase by using word recognition testing and an explicit definition of performance plateau. STUDY DESIGN: Retrospective review. SETTING: Urban, tertiary referral center. PATIENTS: One hundred twenty-five patients with 138 devices tested with AzBio were matched to 130 patients with 138 devices tested with HINT based on performed on CNC monosyllable tests. INTERVENTION: Patient's performance was measured overtime using AzBio and HINT tests to determine when and at what score their performance reached a plateau. MAIN OUTCOME MEASURE(S): Time from implantation to reach a performance plateau and plateau score with each test. RESULTS: Thirty-four devices reached a HINT plateau and 30 devices reached an AzBio plateau. Patients reached plateaus at similar times postoperatively using HINT and AzBio, 18.8 and 16.5 weeks, respectively (p = 0.476). Five patients tested with HINT plateaued at scores of 99% to 100%, whereas no patients plateaued above 92% with AzBio. CONCLUSION: Patients reached a plateau in performance at similar median times using AzBio and HINT, despite the ceiling effect of HINT in some patients. Most patients who reach a plateau did so within 4 months, but exactly when and if a patient's performance plateaus varies significantly among individuals. Further study is required to determine which test best reflects when a patient reaches his or her maximal performance in natural listening conditions.