Nov 2020 The Hearing Journal
Referrals for cochlear implantation remain low and inconsistent despite a cornucopia of evidence demonstrating its benefits for those with sensorineural hearing loss (SNHL), resulting in only a small percentage of eligible adults receiving and using the device, and that's true in many parts of the world, not just the United States. One reason is that international guidelines on adult cochlear implantation candidacy are limited. Without a defined standard of care, clinicians are unsure whether and when to refer a patient with hearing loss to a cochlear implant (CI) clinic. To address this issue, a team of researchers across the globe created the first international consensus paper on unilateral cochlear implantation for adults with bilateral hearing loss.
They gathered a group of 31 clinical specialists in otology, audiology, and hearing science with extensive experience in cochlear implantation to form a Delphi panel. The Delphi study used a systematic literature review and expert opinion to inform the development of consensus statements, said Craig A. Buchman, MD, the Lindburg Professor of Head Otolaryngology—Head & Neck Surgery at Washington University School of Medicine in St. Louis and the lead author of the study. “These statements identify areas that the medical literature and field support strongly, as well as those areas that require further research,” he said. “The next steps are obviously to do more research to address these gaps and develop clinical practice guidelines and advocacy approaches that move the field toward the standard-of-care goals.”
The systematic review included nearly 7,000 papers, and identified seven major areas of interest, which include cochlear implant awareness, diagnosis, surgical implications, clinical effectiveness, factors associated with post-implantation outcomes, association of hearing loss with cognition, depression and social isolation, and cost-effectiveness, Dr. Buchman said. “For this, voting on and modification of the statements had to occur through multiple rounds across the globe. Importantly, the international nature of this work provides statements that are relevant to a variety of countries, practice environments, and cultures across the world.”
Twenty statements on the use of unilateral cochlear implants in adults with sensorineural hearing loss were developed, several of which highlight important facts that have not been given enough attention before. One of them is that cochlear implants work really well for appropriate adult candidates, but there is very limited understanding of this in general medical practice and in the community at large, said Dr. Buchman. “While candidacy criteria for cochlear implants are fairly easy to identify, less than 10 percent of candidates ever receive the intervention,” he said. Another crucial piece of information brought forth by these consensus statements is that cochlear implant surgery is a very safe outpatient procedure with few complications.
Perhaps most important of all is the association between hearing loss and cognitive decline among older adults—the panel of experts in this study developed the highest number of consensus statements about cochlear implants and cognitive health out of all the interest areas. The link between age-related hearing loss and cognitive decline is well established, but the paper identified a key evidence gap in the cognitive benefits of cochlear implants on older adults with hearing loss. The authors were only able to identify one study that demonstrated neurocognitive benefits in older adults after cochlear implantation. They also called for further research to investigate whether the treatment of hearing loss could reduce the risk of developing dementia, given that Alzheimer disease has been associated with central auditory processing disorder and that the incidence of dementia was found to be higher in individuals with age-related hearing loss than in those with normal hearing.
Since cochlear implantation offers an opportunity to improve hearing loss, it may have a positive impact on dementia, said Dr. Buchman. “The literature is growing rapidly in this area, and the importance of depression and cognitive decline on the quality of life amongst adults is substantial,” he said. “Also, hearing loss is the single largest modifiable risk factor for dementia, and cochlear implants offer an opportunity to intervene. This is very important information for the elderly in our society.”
These consensus statements provide audiologists with an opportunity to identify CI candidates in their practice for referral to cochlear implant teams, said Dr. Buchman. “Importantly, this should not result in losing the patient to an implant centre,” he said. “Rather, it should open opportunities for collaboration that ultimately improves patient performance and quality of life.”
This paper is only the first step towards improving the CI utilisation rate in the country and abroad. “Going forward, really, our charge is to disseminate this information to various stakeholders in the world at large,” said Dr. Buchman. “That requires engaging many people, organisations, consumer and advocacy groups, as well as regulators and other individuals across the globe. In some places, this might ultimately be used to change or develop clinical practice guidelines. In other places, it might be used to change the way that these patients are managed at a more local level. Obviously, we're hoping to adopt these as clinical practice guidelines in the United States and ultimately affect decision and policymakers.”