For Whom Do Cochlear Implants Work Best?

Abstract

In this issue of JAMA Otolaryngology-Head & Neck Surgery, Zhao and colleagues 1 report a meta-analysis on the association of preoperative patient-related factors with adult cochlear implant (CI) speech perception outcomes. Through pooled analysis, encompassing 13 articles and 1095 patients, the authors demonstrate statistically significant, yet modest at best, association between postoperative CI speech perception measures and commonly used variables: age of implantation (r = −0.31), duration of hearing loss (HL) (r = −0.25), preimplant pure-tone average (r = −0.16), and preoperative aided word recognition scores (WRS) (r = 0.22).Classic studies from Blamey and colleagues, 2 Holden and colleagues, 3 and Lazard and colleagues 4 have demonstrated similar findings. The relatively large-scale study by Blamey and colleagues 2 followed more than 2251 patients across 15 institutions and found that these traditional factors account for approximately 10% of the variance in CI speech perception performance. A separate analysis by Lazard and colleagues 4 of the same data set but using different models demonstrated that the combination of duration of moderate HL, hearing aid (HA) use, pure-tone average and threshold at 500 Hz in the better ear, CI manufacturer, and percentage of active electrodes accounted for only 22% of the variance in CI speech perception performance. Taken together, these findings alongside those of Zhao and colleagues, 1 are enigmatic when one considers the fact that preoperative aided speech perception testing (consonant-nucleus-consonant words and AzBio sentences) is the main candidacy criteria for determining CI eligibility in nearly all centers and among payers. Although these tests do well at identifying individuals with poor hearing, and thus CI candidates, they do not identify the degree to which an individual will gain benefit.In theory, the best performance predictors would be those measures that represent biomarkers of auditory system integrity. CIs attempt to synchronize auditory nerve depolarization within the spectral and temporal domains to activate the central auditory pathways to improve audibility, speech understanding, and music appreciation, among other facets. It stands to reason that the status of the peripheral cochlearneural substrate in conjunction with the central auditory and nonauditory stations play a major role in determining a patient's performance using a CI. 3 Implant recipients typically do very well with their implants, although performance is variable. Holden and colleagues 3 and many others have demonstrated similar mean consonant-nucleus-consonant word scores (approximately 62%) at 6 months of use with modern technology. Thus, the poor correlation between speech perception performance and the common preoperative biographi-

Individual Patient Comorbidities and Effect on Cochlear Implant Performance

“…Out of 560 patients, only 41 patients had CNS comorbid conditions, and subanalysis of this group did not demonstrate any significant correlation with CNC scores (Supplemental Data, http://links.lww.com/MAO/B846). As we look to the future of precision medicine, an ideal model for CI performance prediction necessitates measurements of both peripheral and central function (58). Although comorbidities demonstrate a significant effect on CI speech perception outcomes that is most pronounced in noise, future studies will need to further evaluate the relationship between cognition and comorbidity index in the CI population.…”