Appendix QResearch recommendations

Publication Details

Q.1. Hearing loss prevalence in people who under-present for hearing loss

Research question: What is the prevalence of hearing loss amongst populations who under-present for possible hearing loss?

Why this is important:

The research question aims to identify the prevalence of hearing loss among populations who may be unaware of their own hearing loss or lack motivation and capability to seek help for this.

A full population prevalence study matched to audiology service usage will help identify populations who under-present for possible hearing loss. The research will also identify factors that can act as red flags to prompt health and social care professionals to proactively consider the possibility of hearing loss.

The evidence review for the NICE guideline on adult hearing loss highlighted significant health benefits for people whose hearing loss is identified and addressed at an early stage, yet people often delay seeking treatment for up to 10 years.133,151 There are certain groups who are particularly disadvantaged because their health issues lead to a lack of awareness of their deteriorating or suboptimal hearing, or a failure to report their difficulties. These include those with learning (intellectual) disabilities, dementia and mild cognitive impairment.

Given the importance of early detection, this research is urgently needed to identify populations who are under-represented and any factors that would lead healthcare and social care professionals to consider the possibility of hearing loss.

Criteria for selecting high-priority research recommendations.

Table

Criteria for selecting high-priority research recommendations.

Q.2. Use of hearing aids and incidence of dementia

Research question: In adults with hearing loss, does the use of hearing aids reduce the incidence of dementia?

Why this is important: In the ageing UK population, the incidence of dementia is increasing. Dementia has considerable long-term costs for people with dementia, their families and the NHS and there is no effective treatment to prevent its progression.

Hearing loss is associated with an increased incidence of dementia. It is estimated that among people with mild to moderate hearing loss the incidence of dementia is double that of people with normal hearing, and that the ratio increases to 5 times that of people with normal hearing in those with severe hearing loss. The cause of this association is unknown; there may be common factors causing both dementia and hearing loss, such as lifestyle, genetic susceptibility, environmental factors or age-related factors such as inflammation and cardiovascular disease. Hearing loss may cause dementia either directly (for example, neuroplastic changes caused by deprivation or increased listening demands) or indirectly via social isolation and depression (which are known be associated with cognitive decline and dementia). Conversely, it is possible that cognitive decline has an impact on sensory function (for example, affecting attention and listening skills). Currently, there is no good evidence to show that hearing loss causes dementia or that hearing aids delay the onset or reduce the incidence of dementia. Hearing aids do, however, have the potential to improve functioning and quality of life, and this could delay the progress of dementia or improve its management.

Criteria for selecting high-priority research recommendations.

Table

Criteria for selecting high-priority research recommendations.

Q.3. Earwax

Research question: What is the clinical and cost effectiveness of microsuction compared with irrigation to remove earwax?

Why this is important: A build-up of earwax in the ear canal can cause hearing loss and discomfort, contributes to infections and can lead to stress, social isolation and depression. Moreover, earwax can prevent adequate clinical examination of the ear, delaying investigations and management; GPs cannot check for infection and audiologists cannot test hearing and fit hearing aids if the ear canal is blocked with wax. Excessive earwax accumulation is common, especially in older adults and those who use hearing aids and earbud-type earphones. In the UK, it is estimated that 2.3 million people each year have problems with earwax sufficient to need intervention.

Earwax is usually treated initially with ear drops. However, if this is unsuccessful, the wax can be removed using irrigation (flushing the wax out using water) or microsuction (using a vacuum to suck the wax out under a microscope). There are few studies comparing these different techniques in terms of effectiveness, cost effectiveness and adverse events.

Criteria for selecting high-priority research recommendations.

Table

Criteria for selecting high-priority research recommendations.

Q.4. Idiopathic sudden sensorineural hearing loss

Research question: What is the most effective route of administration of steroids as a first-line treatment for idiopathic sudden sensorineural hearing loss?

Why this is important: Idiopathic sudden sensorineural hearing loss (SSNHL) affects approximately 5 to 20 people per 100,000 per year80,176,371,528 and accounts for up to 90% of cases of SSNHL. The hearing loss is usually unilateral, can range from mild to total and can be temporary or permanent. Idiopathic SSNHL has a significant impact on people’s lives, causing considerable concern and disability, particularly if there is already a hearing deficit in the other ear.

First-line treatment options for idiopathic SSNHL can include oral steroids, intra tympanic steroid injections or a combination of both. There is a paucity of evidence assessing the effectiveness of these different treatment options. There is heterogeneity in doses and types of steroids and this makes the findings unreliable. Therefore, it is difficult to establish the most clinically and cost effective route of administration of steroids as first-line treatment for idiopathic SSNHL. This has a direct impact on the care provided to people with SSNHL and on our ability to develop robust guidelines and policy.

Criteria for selecting high-priority research recommendations.

Table

Criteria for selecting high-priority research recommendations.

Q.5. Decision tools

Research question: What is the clinical and cost effectiveness of person-centred, decision-making tools when agreeing the preferred management strategy for hearing loss in adults?

Why this is important: Hearing aids are effective in managing hearing loss in adults, and are routinely offered as the first-line clinical management for hearing difficulties. However, hearing aids are not always used. This impacts on healthcare resources, and for the individual, the consequences of untreated hearing loss remain, impacting on quality of life. There are a wide range of interventions to address hearing loss (for example, communication strategies, assistive listening devices, personal sound amplification products and auditory training), each with their advantages and limitations.

The systematic review for the NICE guideline on hearing loss found a lack of studies that addressed the benefits of patient-centred decision-making tools. Robust research is needed to establish the clinical and cost effectiveness of patient-centred tools, and to understand how they might best be used in clinical practice. This will inform future guidelines and policy.

Criteria for selecting high-priority research recommendations.

Table

Criteria for selecting high-priority research recommendations.

Q.6. Assistive listening devices

Research question: What is the clinical and cost effectiveness of assistive listening devices (ALDs) in supporting adults with hearing loss, compared with other devices, combination of devices or no intervention to support adults with hearing loss?

Why this is important: Hearing loss is highly prevalent. Not all people with hearing loss choose or would benefit from hearing aids, as their individual needs, such as personal safety, may be situation-specific. Assistive listening devices, like hearing aids, make sounds more audible. They cover a range of functions, which can be broadly classified into improving communication (for example, remote microphones, personal sound amplification products (PSAPs), improving listening (for example, television loops), and increasing awareness of environmental sounds (for example, amplification, vibration or flashing lights for doorbell, telephone ring, fire alarm). The systematic review undertaken for the NICE guideline on hearing loss identified a paucity of robust evidence for the clinical or cost effectiveness of ALDs, compared with other devices, combination of devices or no intervention. Evidence that ALDs are clinically effective could enable the design of new patient pathways and service delivery models. This could improve financial efficiency and improve outcomes for patients.

Criteria for selecting high-priority research recommendations.

Table

Criteria for selecting high-priority research recommendations.

Q.7. Outcome measures for effectiveness of hearing aid features

Research question: What is the most suitableoutcome measure to use when investigating the clinical and cost effectiveness of directional microphones and adaptive (digital) noise reduction?

Why this is important: The most common complaint of adults with hearing loss is difficulty understanding speech in the presence of background noise or competing speech. Because hearing aids cannot improve deficits in frequency, temporal and spatial resolution, an adult with hearing loss may continue to experience some difficulties, even when wearing hearing aids. The perception, and acceptance, of hearing aids is likely to be improved if they can be shown to improve listening to speech in the presence of background noise.

One hearing aid option that has been developed to distinguish speech from noise, and improve the speech-to-noise ratio (SNR), is the directional microphone. In contrast to omnidirectional microphones, which respond equally well to sounds arriving from all directions, a directional microphone is more sensitive to sounds from one direction (for example, speech coming from directly in front of the hearing aid user), and less sensitive to other directions (for example, background noise from the side or behind the hearing aid user). Directional microphones have the potential to benefit all hearing aid users. A potential disadvantage is that the signal of interest to the hearing aid user may come from a location where the microphone is least sensitive (such as from behind). Modern hearing aids generally have microphones that can be enabled as omnidirectional or directional, usually involving the user selecting a different setting or programme on the hearing aid. Directional microphones have been shown to be efficacious in the research laboratory although their effectiveness in the real world is less clear.

Amplification of background noise can be reduced using digital (or adaptive) noise reduction. The aim of a hearing aid that has adaptive noise reduction is to provide less amplification to noise than to speech. This is achieved by identifying the frequencies (or time) where noise is particularly intense, relative to speech, and applying less amplification. Again, users often have the option of enabling/disabling the noise reduction setting on the hearing aid.

There is a lack of good quality evidence on what is an appropriate primary outcome measure when assessing the real-life effectiveness of directional microphones and adaptive noise reductions. Studies have generally reported benefits in terms of improvements in speech recognition (or SNR) but it is not always clear that this results in real-life benefit. In addition, the SNR remains unchanged with adaptive noise reduction, but there is the potential to improve listener comfort and reduce listening effort, which may prevent decrements in performance over the course of the day.

Criteria for selecting high-priority research recommendations.

Table

Criteria for selecting high-priority research recommendations.

Q.8. Monitoring and follow-up for adults with hearing loss

Research question: What is the clinical and cost effectiveness of monitoring and follow-up for adults with hearing loss post-intervention compared with usual care?

Why this is important: The systematic review for the NICE guideline on hearing loss found a lack of evidence to establish the benefits of monitoring and follow-up, how they should be delivered and across what time periods. Robust evidence is needed to establish the clinical and cost effectiveness of monitoring and follow-up, and to understand how and when they might best be used in clinical practice. This will inform future guidelines and policy.

Criteria for selecting high-priority research recommendations.

Table

Criteria for selecting high-priority research recommendations.