Delayed Cochlear Implantation in Adults with Prelingual Severe-to-profound Hearing Loss

Objectives: To evaluate the results of late cochlear implantation in prelingually deaf patients with significant residual hearing loss and to evaluate patient factors relevant to postoperative auditory outcomes in this patient group.

Study Design: Analysis of results of cochlear implantation using postoperative speech perception test scores per each condition.

Setting: Tertiary referral center.

Patients: Thirty-two subjects with severe to profound hearing loss that developed before the age of 4.

Interventions: Subjects were implanted at a mean age of 24.8 years (range, 16-44) with Nucleus CI24 (n = 18, 56%), Clarion HiRes 90K (n = 11, 34%), and Medel PULSA (n = 3, 10%) device. Details of etiology, duration of deafness, hearing aid history, hearing thresholds before operation, communication mode, and educational environment were investigated. Speech perception tests were performed preoperatively and 12 months after the operation.

Main Outcome Measures: Postoperative speech perception test scores between different options within patient group.

Results: : The results showed significant improvement in open set speech perception (sentence) scores after the implantation (mean scores from 7.0 to 46.7, p < 0.05). Preoperative hearing of better ear and preoperative speech perception scores correlated with postoperative performances (r = -0.70 and r = 0.46, respectively, p < 0.05). Education and communication mode were also closely related to postoperative performances. In the group with poorer performances, preoperative hearing thresholds were significantly worse than those with better performances, and a larger portion of those patients attended special schools and used sign language.

Conclusion: We found that residual auditory capacity in the better ear is an important factor in predicting outcomes after cochlear implantation in patients with prelingual hearing loss.