Title: Feasibility of conducting a randomised control trial to examine the benefit of bilateral cochlear implantation compared with unilateral cochlear implantation in adults with severe to profound deafness
Funder: Department of Health and Social Care

Abstract: The standard of care for severe-to-profoundly-deaf adults in the United Kingdom is cochlear implantation in one ear (unilateral implantation), which restores the ability to understand conversational speech in quiet listening conditions (UKCISG, 2004a). A systematic review commissioned by the National Institute for Health and Clinical Excellence (NICE) established that this is an effective and cost-effective intervention (Bond et al., 2009). Placing implants in both ears (bilateral implantation) can improve the perception of speech in noisy situations (Litovsky et al., 2006) and reduce listening difficulties (Summerfield et al., 2006). However, there uncertainty around the size of the additional benefit to health-related quality of life (HRQoL) that bilateral implantation provides over and above unilateral implantation, and therefore whether bilateral implantation is cost-effective (Bond et al., 2009). NICE recommended that a randomised controlled trial be conducted to compare the health benefits of providing one or two implants (NICE, 2009). The aims of the current study are to assess whether such a trial would be feasible to conduct and acceptable to patients and clinicians. The study has four objectives. The first objective is to design a trial that is acceptable to patients and clinicians. Patient focus groups will explore issues such as acceptance of randomisation, how to minimise the burden associated with participating in a future trial, and potential barriers to participation. Surveys will capture the views of the wider population of patients and clinicians. A workshop with clinicians will seek to establish a consensus on acceptable trial design elements from a clinical perspective. A manufacturers forum will be convened at which a trial design informed by these consultations will be presented to assess whether they would be likely to support such a trial through the provision of devices and excess treatment costs. The second objective is to evaluate the capacity of cochlear implantation service providers to screen adult patients. Providers of adult cochlear implantation services in the UK will screen adult patients referred to their implantation services over a 12-month period against the inclusion/exclusion criteria for the proposed trial. The screening data will be used to estimate the proportion of adult referrals who would be eligible to participate in the trial and to determine how many recruiting sites would be needed. The third objective is to determine the sample size required to detect the expected difference in HRQoL between bilaterally- and unilaterally-implanted adults. HRQoL will be measured using a preference-based health-status questionnaire designed to be sensitive to the benefits of restoring hearing, the York Hearing-Related Quality of Life (YHRQL) questionnaire. To inform a sample-size calculation, the variability of these quality of life scores will be quantified by administering the questionnaire to adults who are currently eligible to receive an implant pre-operatively and at 1, 3, and 6 months after implantation. The fourth objective is to gather information about current care pathways for cochlear implantation to inform the assessment of cost-effectiveness that would be conducted as part of the future trial. A working group of implant service coordinators/heads of service will examine the existing care pathway model to identify aspects of the model that now require updating. By referring to their own service records, the group will seek to reach a consensus on an up-to-date model of the care pathway for cochlear implantation in the UK. Finally, an assessment of feasibility will be made based on whether: (a) the trial could be acceptable to both patients and clinicians; (b) a sufficient number of patients could be recruited over a reasonable time period. The feasibility of using the YHRQL as the primary outcome will be assessed based on completion rates before and after implantation.

Lay abstract: A cochlear implant is a device that can restore some hearing to a deaf ear. In the UK, cochlear implantation is the standard treatment for adults with severe-to-profound deafness. This level of deafness means that without a cochlear implant these adults have difficulty understanding what people are saying even when they wear hearing aids. They have difficulty using the telephone and may be unable to hear important sounds like alarms, doorbells, and traffic. The NHS provides a cochlear implant for one ear even though these adults are deaf in both ears. Two cochlear implants could help them understand speech in noisy environments, know where to look to see who is talking, and avoid hazards outdoors. The decision about who can receive cochlear implants and how many they can receive is based on guidance from the National Institute for Health and Care Excellence (NICE). NICE agreed that providing two cochlear implants can provide additional benefits over providing just one implant. However, they decided that there is not enough evidence to show that these additional benefits are worth the additional cost of providing the second implant. NICE recommended that a clinical trial should be conducted to gather this evidence. To see if that trial could be conducted, this study will work with adults with severe-to-profound deafness and cochlear implant users to understand whether patients would be willing to take part in the trial recommended by NICE. Patients will help design the trial so that it is easy for future patients to take part. The study will work with the clinicians at implant centres to check how many adults may be able to take part and how many will be needed. The researchers will work with patient organisations and hearing charities so that patients know about the study and learn about the results.

Research activity codes: 6.3 MEDICAL DEVICES
Health categories: EAR