Date of Degree
Speech Pathology and Audiology
hybrid cochlear implant, electric acoustic stimulation, hearing preservation, severe to profound hearing loss, cochlear implant candidacy, speech outcomes
Objective: The goal of this review is to systematically review literature in order to investigate the speech recognition and subjective performance outcomes, as well as determine the degree of hearing preservation, in adult hybrid cochlear implant patients through the utilization of electric acoustic stimulation (EAS).
Methods: A comprehensive search, utilizing various peer-reviewed databases, was conducted via the City University of New York’s (CUNY) Graduate Center Library to identify the relevant studies published. Inclusion criteria was studies that involved adult hybrid cochlear implant users which reported speech outcomes and hearing preservation, with performance outcomes obtained at least 12 months’ post-implantation. Studies published before 2013 were not included in this study in order to represent current literature in the field.
Results: Ten studies met the inclusion and exclusion criteria for this systematic review. These studies included various materials to assess both speech recognition performance and subjective outcomes. All studies also reported on the degree of hearing preservation maintained post-implantation. Results revealed that, overall, subjects experienced a significant improvement in speech recognition scores in quiet and in noise. The benefit of utilizing acoustic stimulation, in addition to traditional electric stimulation through the cochlear implant, was also of note. Subjects had an overall positive improvement in subjective outcomes following hybrid cochlear implantation. Varying degrees of hearing were preserved after surgery, with the overwhelming majority maintaining “functional” hearing for EAS.
Discussion: Significant improvements were found pre-to post-operatively in speech recognition outcomes and in subjective report. From this it can be concluded that these individuals, who would not have been traditional cochlear implant candidates, experienced significant positive changes from hybrid cochlear implantation. Additionally, high degrees of hearing preservation were maintained following surgery, further supporting the notion that cochlear implant candidacy criteria should be expanded to include this population. Future research may focus on the discontinued use of EAS, audiologist referral of this population, and the quantifying of benefit of the acoustic component in the hybrid cochlear implant system.
Conclusion: This systematic review assessed the literature regarding speech outcomes, subjective outcomes, and hearing preservation of hybrid cochlear implant users. The positive findings concluded in this review many serve as justification and evidentiary support of the expansion of cochlear implant criteria to include this underserved population.
Key words: “hybrid cochlear implant”, “electric acoustic stimulation”, “speech outcomes”, “speech recognition”, “subjective outcomes”, “quality of life outcomes”, “hearing preservation”, “hearing preservation surgery”.
Dillon, Victoria J., "Speech Outcomes and Hearing Preservation in Adults with Hybrid Cochlear Implants: A Systematic Review" (2020). CUNY Academic Works.