Professor Anne Schilder on the links between hearing loss and dementia
Professor Anne Schilder investigates the links between hearing loss and dementia.
Anne Schilder is a Professor of Otolaryngology UCL Ear Institute, Consultant ENT Surgeon Royal National ENT and Eastman Dental Hospital UCLH Trust and Director NIHR UCLH BRC Hearing Health Theme.
What attracted you to investigate the links between hearing loss and dementia?
The 2017 report by the Lancet Commission ‘Dementia prevention, intervention, and care’ sparked a worldwide interest in this topic. The UCL researchers who led the Commission (Livingston, Costafreda) pulled together all cohort studies that included measures of hearing and cognitive health and found that hearing loss acquired in mid-life is associated with an increased risk of dementia (Livingston 2017).
The Commission estimated that if we could ‘eliminate’ hearing loss, the risk of dementia could be reduced by 8%. The topic interested me personally as I felt that our NIHR UCLH Biomedical Research Centre would be able to answer many of the questions that arose from the Lancet Commission’s findings: What is the nature of this association, how do we best diagnose and manage hearing loss and dementia in people at risk, and what do we need to do to implement this knowledge into our clinical practice?
What are some of the main challenges in diagnosing and addressing the issue of hearing loss and cognitive impairment?
We have not fully unravelled what is behind the association between hearing loss and dementia: Does hearing loss cause dementia or does dementia affect our ability to process sound and speech?
Research supported by our BRC has shown that older people with hearing loss score lower on a memory test that is based on spoken instructions, compared to people without hearing loss. They have therefore adapted those memory tests into a visually based version (Utoomprurkporn 2021).
Similarly, in people with mild cognitive impairment, pure tone audiometry, the gold standard to diagnose hearing loss, does not reflect the hearing difficulties they perceive (Utoomprurkporn 2021). We are therefore developing better hearing assessments for people with hearing problems (Jiang 2023).
We have also approached this question of mechanisms by analysing existing big datasets and found that there is no evidence to support the idea that the same genetic risk factors cause both dementia and hearing loss, but they might be linked by common vulnerabilities in the same pathways (Zainul Abidin 2021).
Ongoing work also suggests that people at high genetic risk of hearing loss may progress to full dementia more quickly than those that are at low risk. Building on this we are linking large hospital datasets on hearing and its co-morbidities with local community datasets through the NIHR Hearing Health Informatics Collaborative to better understand the relationship of these conditions across the patient journey.
What treatments can help?
There is emerging evidence that managing hearing loss acquired in mid-life with hearing aids may reduce the risk of developing dementia (Jiang et al 2023; Lin et al 2023). We have shown that people with mild cognitive impairment or dementia struggle with the use of hearing aids (Gregory et al, 2020), which means that they may need extra support.
The team at the UCL Division of Psychiatry has just completed a pilot trial funded by Alzheimer’s Research UK, showing that older people with mild cognitive impairment were happy to take part in a study of timely hearing aid fitting and support. And we found that many more people took up hearing aids. We are currently working towards expanding this pilot into a full trial involving more clinics and patients and measuring cognitive health over several years.
We recently conducted a survey showing that UK audiologists rarely address memory in their hearing services for older people (Omar et al 2023), and internationally there are no guidelines or protocols on how best to introduce this. One of our BRC-supported PhD students is investigating why that is the case and how we can overcome barriers. At the same time, we are developing educational materials for audiologists aiming to improve their practical knowledge about hearing loss and dementia.
Skipping some of these steps we recently completed a pilot study introducing a memory assessment in one of UCLH’s community hearing aid clinics. We found that most patients and their accompanying persons support this, and audiologists feel confident to conduct memory assessments once they have received training. When audiologists are better informed about their patients’ memory, they may adjust their approach and improve hearing aid use.
Do you have plans for future work in this area?
Our NIHR Hearing Health BRC is committed to improve hearing and cognitive health through our research that brings together expertise in genomics, auditory phenotyping, data science, clinical trials, and service innovation. We will continue to work closely with patients and members of the public to ensure this collective expertise is mobilised to deliver our ambitious plans to revolutionise the scientific knowledge and clinical care for people with hearing loss.