Cochlear implantation outcomes in adults: A scoping review

Abstract

Cochlear implantation has become known as "the treatment of choice" for adults with severe to profound hearing loss. Wide variability exists, however, in the way hearing loss severity is measured and in the candidacy criteria used to recommend cochlear implantation. ObjectivesThis study aimed to provide a descriptive analysis of recent evidence available in the literature in relation to the efficacy of unilateral cochlear implantation in adults, the general findings of these studies, and the populations to which these findings apply. It also aimed to appraise the individual success rate and the magnitude of benefit following implantation. DesignA scoping review was conducted to identify English-language, peer-reviewed journal articles published between 2000 and 2018 assessing the outcomes of cochlear implantation in adults who received their first cochlear implant from 2000 onwards. To be included, studies had to report speech perception or self-reported measures of listening or quality of life at least three months after implantation. Systematic searches were conducted in Medline, Embase, Web of Science and Google Scholar. A two-stage screening approach was used, with seven reviewers independently screening titles and abstracts against inclusion criteria and three from this group further reviewing full-texts. A data charting form was developed and trialled, with 10% of the study data extracted in duplicate to compare results and further refine the form. Data relevant for efficacy analyses were extracted from studies with sample sizes of at least 10 participants. ResultsA total of 4182 abstracts were screened against inclusion criteria, and of these, 603 fulltexts were further screened. After exclusion of non-eligible articles, 201 articles were included in the first part of this scoping review. The majority of these articles were case series or comparative studies without a concurrent group, and had small sample sizes. Data PLOS ONECompeting interests: The authors have declared that no competing interests exist. synthesis conducted with the 102 articles with more than 10 participants highlighted that the average word perception ability improved from 8.2% to 53.9% after implantation. Selfreported benefit improved by 21.5 percentage points. At the individual level, 82.0% of adults with postlingual hearing loss and 53.4% of adults with prelingual hearing loss improved their speech perception ability by 15 percentage points or more. A small proportion had poorer ability after implantation or had stopped using the cochlear implant. ConclusionsDespite broad inconsistencies in measurement, research design, and reporting across articles, it is evident that cochlear implantation is beneficial to the majority of adults of any age who have limited aided speech perception abilities. While many adults with severe-to-profound hearing loss may also have poor speech perception abilities with hearing aids, the validity of using hearing loss severity as a criterion for cochlear implantation has not been demonstrated. Clinical and...

Genotype-Phenotype Correlation for Predicting Cochlear Implant Outcome: Current Challenges and Opportunities

“…Despite the initial introduction in 1957 and commercialization, CI became widely used in the last 20 years to provide auditory rehabilitation to individuals having severe to profound SNHL (Macherey and Carlyon, 2014;Eshraghi et al, 2017;Sousa et al, 2018;Boisvert et al, 2020;Sharma et al, 2020). The most distinguishing feature between CI and hearing aids is that hearing aids merely amplify sounds so that they can be detected by the remaining inner ear hair cells in a patient with mild to moderate hearing loss.…”

Neural Tissue Degeneration in Rosenthal’s Canal and Its Impact on Electrical Stimulation of the Auditory Nerve by Cochlear Implants: An Image-Based Modeling Study

“…Therefore, extending the results of the present study to the whole length of the cochlea, we suggest that even a small change in tissue density in RC could disproportionately affect electrical stimulation of the AN along the entire cochlea. Hence, reported inconsistencies in the performance of CIs [ 87 , 88 , 89 ] could be partially attributed to the eventual degeneration of (heterogeneous) neural tissues in RC and perhaps even the generation of aneural tissue. A few in-silico studies have proposed patient-specific and fully automated models to aid CI surgery and evaluation [ 90 , 91 ].…”

Nordic results of cochlear implantation in adults: speech perception and patient reported outcomes

“…Overall, six months after implantation the patients showed excellent improvements in Dantale scores and moderately to excellent improvements in HINT scores. Collecting data from 24 countries on 5 continents, a recent systematic review concluded that 82% of postlingually hearing impaired adult CI recipients achieved a speech perception improvement on the implanted ear of at least 15 percentage points [13]. In addition, the authors found that the weighted average for improvement in quality of life was 21.5 percentage points.…”