Recommendations for research
The guideline committee has made the following recommendations for research. The committee's full set of research recommendations is detailed in the full guideline.
What is the most effective route of administration of steroids as a first-line treatment for idiopathic sudden sensorineural hearing loss?
Idiopathic sudden sensorineural hearing loss (SSNHL) is usually unilateral, can range from mild to total and can be temporary or permanent. 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.
What is the clinical and cost effectiveness of microsuction compared with irrigation to remove earwax?
A build-up of earwax in the ear canal can cause hearing loss and discomfort, contributes to infections, and can exacerbate 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 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, efficiency and adverse events.
In adults with hearing loss, does the use of hearing aids reduce the incidence of dementia?
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 cardiovascular disease. Hearing loss may cause dementia either directly (for example, neuroplastic changes caused by hearing 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.
What is the prevalence of hearing loss among populations who under-present for possible hearing loss?
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. 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 people with learning 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 health and social care professionals to consider the possibility of hearing loss.
The evidence 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.