Over-Hear: assessing functionality of hearing aids in complex listening environments

The World Health Organization (WHO) estimates around 360 million people world-wide have a disabling hearing loss, with significant negative impact on the social and emotional health of individuals and their families, lost education and employment opportunities, and a substantial economic burden for deaf individuals and broader society. Currently, hearing aids are the most common form of therapeutic intervention for hearing loss. Nonetheless, even in high-income countries with established social- or insurance-based health care provision, the uptake and retention of hearing aids remains low; this is despite the lack of alternative treatments and therapies and the enormous personal and societal cost. Independent of differences in culture, economics of health-care provision or even whether or not someone has been provided with or purchased a hearing aid, a principle reason given for stopping using them (or not considering them in the first place) is the broadly held view that they provide little in terms of understanding speech in background noise. Since this is precisely the problem for which most hearing-impaired listeners seek help in the first place, it is unsurprising that this failure to deliver often leads to non-use of hearing aids. Several reasons likely contribute to disappointment with hearing aids, including unrealistic expectations of the devices' capabilities, intermittent use potentially compromising the extent to which the hearing brain adapts to the device, and the undeniable fact that hearing aids, whilst performing an adequate job in terms of amplifying sounds, do not make them very much easier to distinguish from each other; although hearing aids can provide the extra amplification of sounds that is lost when the inner ear is damaged, they cannot restore the frequency resolution (the ability to distinguish one sound from another) that accompanies the loss of sensitivity to quiet sounds. This is compounded by the fact that hearing aids are generally fitted with respect to increasing the audibility of pure tones (the pure-tone audiogram) with little or no regard to the natural listening environments in which most listeners need to perform. Although many putative strategies for enhancing listening in noise are implemented across a range of hearing aids, their rationale and their efficacy are only poorly understood, not least because they are inadequately assessed with respect to individual users' listening and communication strategies. We will establish a consortium of researchers, engineers and clinicians called 'Over-Hear' in order to understand and develop the best means of assessing how individual listeners utilise their hearing aids in complex listening environments. Through a series of Workshops, Over-Hear will seek to determine:- how best measures of listening performance can be assessed; how listeners behave in complex listening environments; the evidence needed to determine whether technological advances in hearing-aid processing are effective; the range of different performance levels in hearing-aid use by individual listeners. Our consortium will also conduct a Pilot Study in a specially designed arena that can recreate different sound and physical environments whilst simultaneously measuring behavioural (e.g. head movements towards or away from sound sources) and objective neural measures (e.g. brain activity that informs us as to how well hearing-aid users are listening and communicating). This might inform, for example, which selectable signal-processing strategies ('settings') a user employs, how this alters understanding of speech and communication strategies in complex listening environments, and could lead to the development of 'smart' hearing aids sensitive to users' listening intentions.

Hearing aids are generally fitted with respect to increasing the audibility of pure tones (the pure-tone audiogram) with little or no regard to the natural listening environments in which most listeners need to perform. Although many putative strategies for enhancing listening in noise are implemented across a range of hearing aids, their rationale and their efficacy are only poorly understood, not least because they are inadequately assessed with respect to individual users' listening and communication strategies.
We will develop a collaborative network 'Over-Hear' to determine how listeners behave in complex listening environments and how measures of listening performance can be assessed and analysed. A Working Group (the co-PIs plus the two additional core partners) will develop and drive the programme of activity, including scoping and developing 3 key Workshop topics assessing technical requirements and feasibility of acquiring and analysing physiological/behavioural data from users in complex listening conditions. The Working Group will also develop and deliver a Pilot Study to assess the feasibility of recording a range of user-generated data in the UCL 'PAMELA' (http://www.ucl.ac.uk/arg/pamela) environment. Running over the course of the Over-Hear project, the Pilot Study will provide the first steps in developing a larger-scale study to generate the data required to inform, for example, which selectable signal-processing strategies ('settings') a user employs and how this alters understanding of speech and communication strategies in complex listening environments. Given the relatively short (18 months) of the project, and the need first to scope the specific forms of auditory and physiological measurement that need to be undertaken, the Pilot Study will necessarily be relatively constrained in its scope, but will inform future research projects and grant-funding applications.

We envisage three main groups/areas of benefit from this project.

First, Scientists, engineers and clinicians interested in advancing hearing-aid technologies and in understanding current limits, and future potential, of new perspectives on hearing aids, for example through augmented sources of brain or behavioural information to help 'steer' hearing aids. Engineers such as those overseeing the PAMELA facility will also helped in developing new technologies and techniques for assessing performance of hearing aids (and hearing-aid users) in more 'life-like' listening conditions. The PAMELA facility could form a national centre for assessment in this regard.

Second, hearing-aid users and their families. Our engagement with 'evidENT' (http://www.ucl.ac.uk/ear/evident) has the potential for significant impact, not least because this is a NIHR-funded programme strongly links with local and national clinical and research centres, and with a remit for increasing the number of clinical trials in ENT medicine, including for hearing devices. 'evidENT' is also well connected to commercial groups in the field. With regard to public policy on hearing aids, two specific groups will be engaged, not least because they have a strong advocacy perspective, including within Whitehall. Action on Hearing Loss (AoHL, http://www.actiononhearingloss.org.uk/), the largest support and research group for hearing and deafness, and the Ear Foundation (http://www.earfoundation.org.uk/) based in Nottingham are both influential with user groups (e.g. hearing-aid users, teachers of the deaf) as well as with policy makers and the academic, clinical and commercial sectors. The Ear Foundation, for example, is championing a cross-parliamentary drive for adult hearing screening, and we will support this perspective by providing evidence of hearing function with hearing aids 'beyond the audiogram'. Another level of engagement is with groups like the Department of Transport, with whom Professor Nick Tyler has long-standing interactions (including research and contributions to policy). Hearing-aid users in public spaces (from railway stations to banks) are at a severe disadvantage given the often complex and noisy listening conditions (railway-station announcements being a particular problem, for example). Understanding how environments might be arranged so as to better help hearing-impaired listeners is within the scope of the project, and we will explore the means of engaging the Department of Transport and other Whitehall entities in understanding and ameliorating the problem of impaired listening-in-noise.

Third, at a commercial level, we consider the potential impact on the UK's commercial activities to be potentially critical. Not one of the hearing aid manufacturers (or cochlear implant companies) is British, and none of the companies has a large R&D base in the UK (despite cross-national and cross-continental seeding of large research centres by the various companies). This is a clear anomaly, especially given the strong research base across the UK in hearing research. Through demonstrating the potential for high-quality, commercially important (i.e. translational) research within the UK academic sector, Over-Hear has the potential to change this by i) bringing commercial partners to the UK to establish larger R&D programmes and, ii) by providing a forum in which new technological advances in hearing/medical devices can be explored. There is significant interest by 'start-ups' in engaging hearing devices with 'smart-phones' and other mobile devices, and Over-Hear provides a potential forum for exploring new commercial perspectives, including how best to assess multi-sensory/behavioural data and to exploit it in devices.