Implantable Devices for Single-Sided Deafness and Conductive or Mixed Hearing Loss: A Health Technology Assessment.

backgroundSingle-sided deafness refers to profound sensorineural hearing loss or non-functional hearing in one ear, with normal or near-normal hearing in the other ear. Its hallmark is the inability to localize sound and hear in noisy environments. Conductive hearing loss occurs when there is a mechanical problem with the conduction of sound vibrations. Mixed hearing loss is a combination of sensorineural and conductive hearing loss. Conductive and mixed hearing loss, which frequently affect both ears, create additional challenges in learning, employment, and quality of life. Cochlear implants and bone-conduction implants may offer objective and subjective benefits of hearing for people with these conditions who are deemed inappropriate candidates for standard hearing aids and do not meet the current indication (i.e., bilateral deafness) for publicly funded cochlear implants in Canada.

methodsWe conducted a health technology assessment, which included an evaluation of clinical benefits and harms, cost-effectiveness, budget impact, and patient preferences and values related to implantable devices for single-sided deafness and conductive or mixed hearing loss. We performed a systematic literature search for systematic reviews and cost-effectiveness studies of cochlear implants and bone-conduction implants, compared to no interventions, for these conditions in adults and children. We conducted cost-utility analyses and budget impact analyses from the perspective of the Ontario Ministry of Health to examine the impact of publicly funding both types of hearing implants for the defined populations. We also interviewed 22 patients and parents of children about their experience with hearing loss and hearing implants.

resultsWe included 20 publications in the clinical evidence review. For adults and children with single-sided deafness, cochlear implantation when compared with no treatment improves speech perception in noise (% correct responses: 43% vs. 15%,

conclusionsBased on evidence of moderate quality, cochlear implantation and bone-conduction implants improve functional and patient-important outcomes in adults and children with single-sided deafness and conductive or mixed hearing loss. Qualitative results of interviews with patients are consistent with the findings of the systematic reviews we examined.Among people with single-sided deafness, cochlear implants may be cost-effective compared with no intervention, but bone-conduction implants are unlikely to be. Among people with conductive or mixed hearing loss, bone-conduction implants may be cost-effective compared with no intervention. Results and uncertainty are mainly driven by changes in health utilities associated with having a hearing implant. Hence, further research on utility values in this population is warranted with larger sample sizes and longer follow-up.The 5-year cost of publicly funding both types of hearing implant for single-sided deafness and conductive or mixed hearing loss in Ontario is estimated to be $6.7 million to $7.8 million.