Experience of adult cochlear implantation at a tertiary hospital

The prevalence of adult cochlear implant (CI) surgery is increasing. However, the relevant adult CI data in Taiwan are insufficient due to the relatively small number of adult implant patients. The two main factors hindering adult implantation are the high cost of the surgery itself and inadequate knowledge regarding the effectiveness of CI for hearing and suppression of tinnitus. Here, we present data regarding adult CI outcomes from a single tertiary hospital.

A total of 116 consecutive adult CI recipients (≥18 years old) who completed at least 12 months of speech perception tests (words and sentences) between January 1999 and December 2020 were enrolled in this retrospective population-based cohort study. Thirty patients completed speech perception (words and sentences) testing as well as three questionnaires relating to quality of life, and 71 completed full tinnitus suppression studies. Subjects' pre- and post-CI questionnaires were evaluated to assess overall CI outcome.

For auditory evaluation, the scores of easy sentences (ES), difficult sentences (DS), and phonetically balanced (PB) word recognition tests reached a plateau at 3 months post-CI (p = 0.005, 0.001, and 0.004, respectively) in most subjects. The post-CI scores of bodily pain, mental health, and social role functioning were significantly higher than corresponding pre-CI scores on the SF-36 Health Survey-Taiwan version (p = 0.036, 0.019, and 0.002, respectively). Furthermore, the post-CI scores of basic sound perception, speech production, and advanced sound perception were significantly higher than the corresponding pre-CI scores on the Nijmegen Cochlear Implant Questionnaire (p < 0.001, 0.013, and <0.001, respectively). Self-esteem was significantly correlated with the Categories of Auditory Performance scale and Speech Intelligibility Rating scale at 3, 6, and 9 months post-CI. CI improved tinnitus in approximately 65.1% of 71 adults. Based on the Tinnitus Handicap Inventory, 66.7% of patients were in grade 3-5 before surgery. However, after CI, only 34.4% of patients remained in THI grade 3-5.

This study confirmed that CI can improve speech perception (words and sentences), physical health, mental health, social interaction, and self-esteem in adult patients with profound hearing loss. CI also significantly alleviated tinnitus. The outcomes of ES, DS, and PB tests at 3 months post-CI were non-inferior to other longer post-CI periods and could be utilized as references for recovery and evaluation of prognosis.