Personalized fitting and evaluation of hearing aids with EEG responses

Lead Research Organisation: University of Southampton
Department Name: Faculty of Engineering & the Environment

Abstract

It has been estimated that some 6 million people in the UK could benefit from hearing aids, but there are only approximately 2 million hearing aid users, and of these, only 70% use their hearing aids regularly. Modern hearing aids are complex devices with advanced features (gain in different frequency bands, amplitude compression, feedback cancellation, noise reduction, directional microphones etc.) and require professionals to fit them. Limited benefit from hearing aids is a major reason why many patients do not use their devices regularly. Conventionally, hearing aids are fitted based primarily on the 'audiogram', which informs on the quietest sounds (short tones) that the patient can hear at different frequencies and is obtained from patients' voluntary and subjective response (usually by clicking a button) to progressively quieter sounds. However, it is clear that the audiogram only provides limited insight into hearing loss, and fitting hearing aids based on this alone can lead to very diverse results in what is of most importance to patients, namely understanding speech. The difficulty of understanding speech in noise is one of the chief complaints of hearing aid users.

The current project aims to improve personalized fitting of hearing aids to individual patients. The key technique will be the use of measurements taken directly from the brain's response to sound, by analysing the electroencephalographic (EEG) responses obtained from electrodes placed on the scalp. The analysis is 'objective', without requiring patients' voluntary and 'subjective' (and not always reliable) response to stimuli. We think this is important as it can be carried out in patients who are unable to provide such voluntary responses, for example infants or the elderly with dementia. By monitoring hearing without constant interruption to assess patients' perception, the performance of the hearing aid can also be assessed in natural listening conditions and over a longer time period. Ultimately this approach may also allow hearing aid settings to be adjusted without the presence of an audiologist, as users' needs and the auditory environment change. The test stimuli (hearing challenges) we will develop for the project will include a wider range of sounds than are currently routinely used in clinics, allowing for more subtle (differential) diagnosis of hearing loss, and a focus on the response to speech (including speech-in-noise).

The key research aim in this project is to achieve a robust assessment of hearing function and speech processing in the brain (from the cochlea to the brain stem and cerebral cortex) by the computer analysis of EEG responses to complex real-world signals. This presents major scientific and technical challenges, needing the development of novel signal-analysis methods for speech and EEG data, which can be related to hearing impairment, cognition, as well as hearing aid settings and performance. The combination of these major challenges and a focus on patient benefit makes this an exciting and adventurous project.

The main objectives of this proposal are to propose, assess and recommend:
1. Signal processing methods to extract information from EEG signals on hearing performance and patients' access to speech
2. Stimuli to use in assessing hearing
3. Algorithms to optimize hearing aid fitting, based on parameters extracted from EEG responses

This interdisciplinary work will be carried out as a collaboration between universities (hearing science, speech processing, signal analysis), industry (hearing technologies) and patients (choosing hearing challenges). The benefits of undertaking this work are expected to be to patients and their family and carers (improved quality of life from using hearing aids), the health-services (improved efficiency), industry (new diagnostic technologies) and the scientific community (better understanding of hearing; improved methods for analysing EEG signals).

Planned Impact

This project is expected to have academic, economic and societal impact. Improving hearing aids has been identified as a priority for EPSRC in this particular call for research proposals and fits within its broader strategic goal of improving health-care technologies. This proposal specifically addresses the research challenges in the call for proposals of Optimising hearing aid devices for individuals and Speech-in-noise performance in hearing aid devices.

Research interest related to the effect of speech on the EEG signals and the use of EEG signals in fitting hearing aids has recently increased greatly. This project will be at the leading edge of this international research effort, with a multidisciplinary team that is well placed to spearhead studies in this area, generating new knowledge, understanding and research methods for the field. The currently growing interest in the field makes this project very timely. Through a collaborative approach, sharing data (when possible, given constraints of ethics and data protection) and methods, together with current and up-coming networking activities, we expect this project to further enhance the leadership of UK science in the field. The multidisciplinary team will provide excellent training opportunities, not only for those directly employed in this project, but also for undergraduate and postgraduate students working on projects within related fields. The working environment will allow them to experience close collaborations between engineering, hearing science and audiology, and to obtain hands-on experience in data collection and interaction with clinical scientists and patients. This field of research is also highly amenable to public engagement activities, since it addresses a well-known societal problem whose impact and alleviation can readily be shown with engaging audio demonstrations - and this will be pursued as part of this project.

Of the approximately 6 million people in the UK who could benefit from hearing aids, currently only approximately 2 million have hearing aids, but only some 1.4 million use them regularly. It is now known that hearing impairment is related to depression, reduced educational opportunities and relationship difficulties. Improving hearing aid fitting will result in improved quality of life for an increasing number of patients through better social and work interactions, and this in turn will result in improved economic productivity and societal benefit. Our work also has the potential to improve the efficiency of hearing-aid services through automated fitting approaches. Additional economic impact is expected from new commercial opportunities as the project develops innovative technologies and new diagnostic/treatment services in the public and private sectors. The potential impact of this research has been recognised by the charity Action on Hearing Loss, The British Society of Audiology Special Interest Group in Electrophysiology and a clinician, Katie Ireland, who works with infants with hearing impairment, all of whom have provided supporting statements for this application.

At the end of this project, we expect to leave a legacy of new knowledge and methods with a fresh approach to the field, a closely collaborating research team, well-trained young researchers working on hearing aid technologies within and beyond our group, and follow-on projects moving into clinical trials.

Publications

10 25 50
 
Description A key area of our work has been to develop and evaluate methods to record the response of the brain to speech. We have shown that it is possible to reliable record responses to a range of speech stimuli ranging from very short consonant vowels through to running speech in time scales that looks promising for clinical applications (a few minutes per recording). We can also record such responses through hearing aids. Many of the publications arising from the work have focussed on technical developments in making such recordings, including single and multichannel methods. The partners at Imperial College have developed a new method to measure brainstem level responses to running speech. Partners at Southampton and Manchester have tested methods to robustly record brain responses to stimuli of different lengths and different frequency contents. Some of our work has shown a complex relationship between the frequency content of the speech material presented to the brain and the EEG response obtained. This result means that optimising hearing aids based on the EEG response is an even more complex challenge than expected. We think that evaluating a hearing aid (showing that the aid is making a stimulus audible) using EEG responses may be more achievable in the near term than optimizing the hearing aid. Such an approach may be particularly relevant for infants given hearing aids, as such infants are not able to tell us how a hearing aid sounds, so demonstrating the benefit of an aid would have clinical impact. From the project we now have a range of robust methods to elicit brain responses to speech that are suitable for further clinical evaluation.
Exploitation Route We have developed a range of robust methods to elicit brain responses to speech that are suitable for further clinical evaluation (for example with potential to demonstrate hearing aid benefit in infants, or patients who are unable to cooperate with standard test of hearing).
Sectors Healthcare

URL https://www.southampton.ac.uk/engineering/research/projects/personalised-fitting-and-evaluation-of-hearing-aids-with-eeg-responses.page
 
Description The work on sensitive measures to detect auditory evoked response (Chesnaye, M. A., Bell, S., Harte, J. M., & Simpson, D., 2018) which was in part developed through the current project is being implemented into clinical testing systems by the company Interacoustics. The approaches should lead to reduced testing time and more sensitive measures of hearing threshold in infants who fail newborn hearing screening. The work was also utilised by a PhD student, Faten Obeidat, who was exploring tests of balance function in patients with cochlear implants.
First Year Of Impact 2019
Sector Healthcare
Impact Types Societal

 
Description Postgraduate teaching
Geographic Reach National 
Policy Influence Type Influenced training of practitioners or researchers
 
Description postgraduate teaching
Geographic Reach National 
Policy Influence Type Influenced training of practitioners or researchers
 
Description Oticon Foundation Research Grant
Amount 1,596,369 kr. (DKK)
Funding ID 18-2613 
Organisation Oticon Foundation 
Sector Charity/Non Profit
Country Denmark
Start 01/2019 
End 01/2021
 
Description Personalized fitting and evaluation of hearing aids with EEG responses
Amount £908,086 (GBP)
Funding ID EP/M026728/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 05/2015 
End 08/2018
 
Title Extraction of fundamental waveform from speech 
Description Fundamental Frequency (and higher harmonics) waveform extraction from continuous speech using Empirical Mode Decomposition (EMD). 
Type Of Material Computer model/algorithm 
Year Produced 2017 
Provided To Others? Yes  
Impact The fundamental waveform computed from the algorithm allows, through correlation with the neural response to speech, measure the brainstem response at the fundamental frequency of speech. 
URL https://github.com/elifesciences-publications/fundamental_waveforms_extraction
 
Description Interacoustics 
Organisation Interacoustics A/S
Country Denmark 
Sector Private 
PI Contribution We have established a close collaboration with Industrial partner who specialises in development and commercialisation of new objective assessment methods of hearing. We provide Intellectual Property and access to clinical populations for validation of the developed methods.
Collaborator Contribution The industrial partner provides technical expertise and necessary equipment.
Impact The outputs so far include Conference presentations and posters.
Start Year 2016
 
Description Action on Hearing Loss Potential Funders' Meeting 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Supporters
Results and Impact A visit for potential funders of the Action on Hearing Loss charity was organised at the University of Southampton. A total of about 50 members of the general public joined the meeting. They received an introduction on hearing-related research occurring at the University, and were asked to engage in interactive tutorials performing small experiments, such as measuring the effect of switching on/off the light in the sound booths when collecting data. People showed much enthusiasm for the research, with interest in funding the charity to help the charity in funding future research, as well as being participants in future studies
Year(s) Of Engagement Activity 2017
 
Description Advanced hearing diagnostic course 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A workshop on advanced hearing assessment was delivered to a group of policy makers and practitioners in Ireland.
Year(s) Of Engagement Activity 2018
 
Description Article by the Royal British Legion on research on hearing impairment in veterans 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Supporters
Results and Impact Article by the Royal British Legion on research on hearing impairment in veterans
Year(s) Of Engagement Activity 2017
 
Description BBC radio podcast 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact BBC radio podcast on publication in eLife, The Naked Scientist
Year(s) Of Engagement Activity 2017
 
Description Centre for Blast Injury Studies Networking Event 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Centre for Blast Injury Studies Networking Event at Imperial College London
Year(s) Of Engagement Activity 2017
 
Description Cheltenham Science Festival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Activities were organised for people to experience hearing loss and listening through a hearing aid and cochlear implant using real-time simulators and a music quiz. A demonstration regarding sound localisation was also organised, letting people listen through giant pinnas. The simulations sparked an increased awareness of the effects of hearing loss and an increased appreciation of the difficulties on living with a hearing aid or cochlear implant. Many hearing impaired came over to the demonstration site to ask questions about their hearing loss. Overall, people seemed very satisfied about the performance (based on an informal questionnaire which could be completed on site).
Year(s) Of Engagement Activity 2016
URL http://www.cheltenhamfestivals.com/science/
 
Description National Geographic Radio podcast on hearing, with third-year students at Imperial College 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Other audiences
Results and Impact National Geographic Radio podcast on hearing, with third-year students at Imperial College
Year(s) Of Engagement Activity 2016
 
Description Presentation at a meeting of the Institution of Engineering and Technology 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact David Simpson and Steven Bell gave an invited presentation to a regional meeting of the Institution of Engineering and Technology on 2/2/6016 entitled 'Modern Aided Hearing: More than just an electronic ear trumpet'. The aim was to give a general introduction to a lay audience with technical background on the consequences of hearing loss and the technology of hearing aids. This form part of our proposed outreach activity regarding increasing awareness of the impacts of hearing impairment on quality of life. We also highlighted how our current research for EP/M026728/1 aligns with some of the challenges for the hearing impaired. Quite a few members of the audience were hearing aid users and there was a good discussion around the challenges facing hearing aid users. We intend to use the presentation that was developed for future outreach activities.
Year(s) Of Engagement Activity 2016
 
Description Science and Engineering Open Day 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact The open day demonstration intended to show the impact of hearing loss and living with hearing aids to the general public. It consisted of allowing general public to have their ears checked using a video-otoscope, such that they could be made aware of how their ear can be damaged in case of occlusion (wax or foreign objects). There were 3D ear models displayed which could be taken apart and build up again by members of the public. A demonstrator would also give an overview of how sound is transmitted through the ear. Besides this, there were real-time simulations of hearing impairment and listening through a hearing aid and cochlear implant. Many participants showed an increased awareness of hearing function and the importance of avoiding loud sounds to ensure they would not need a hearing aid.
Year(s) Of Engagement Activity 2016
URL http://www.southampton.ac.uk/per/university/festival/science-and-engineering-day.page
 
Description Science and Engineering Open Day 2017 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact The Science and Engineering Day at the University of Southampton is a yearly event organised by the University as part of the Science and Engineering Week. In 2017, this open day attracted over 7,500 participants of the general public, of which about 800 visited the audiology activity. This activity included demonstrations in which the public actively engaged with experiments in sound localisation (by wearing giant pinnas), experience listening with hearing loss or through a cochlear implant (simulations and quizzes for detecting music) and ear anatomy (video-otoscopy performed by MSc students in Audiology from the University of Southampton). Further explanations were given on how these demonstrations are linked to current research at the University. Participants were fascinated by the work performed at the University and to learn about hearing. Many people commented on how it was helpful for them to understand hearing: an ability many take for granted without really thinking about how it works. With the simulations, we were also able to raise awareness on behaviour that could lead to reduced hearing loss (e.g. listening to loud music) and how to avoid it, but also how to adapt to people who they know have a hearing loss to ensure that these people feel socially involved. Lastly, participants showed interest in participating in future studies on hearing at the University.
Year(s) Of Engagement Activity 2017
URL http://www.southampton.ac.uk/per/university/festival/science-and-engineering-day.page
 
Description Scientific sessions at Camp Bestival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Over 1000 members of the general public joined the festival, at which we demonstrated audiology research as part of a larger scientific session organised by the University of Southampton. The scientific session sparked discussion on future directions of research, and also increased interest of some of the younger generation to pursue a career in research.
Year(s) Of Engagement Activity 2017
URL http://www.campbestival.net/
 
Description The Royal British Legion Legacy Days 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Supporters
Results and Impact The Royal British Legion Legacy Days
Year(s) Of Engagement Activity 2017
 
Description Winchester Science Festival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact More than 1000 members of the general public attended the Science Festival on each of the 3 days. A demonstration was provided where people could experience hearing loss and listening to music through a cochlear implant. People acknowledged a change of view on the difficulties and loss of well-being they believed people with hearing loss had to endure.
Year(s) Of Engagement Activity 2016
URL http://www.festivalsinwinchester.co.uk/event/winchester-science-festival-2