DEVELOPING ELECTROPHYSIOLOGICAL MEASURES OF BRAIN ACTIVITY TO OPTIMISE COCHLEAR IMPLANT OUTCOMES
Lead Research Organisation:
University of Cambridge
Department Name: Clinical Neurosciences
Abstract
For people with insufficient hearing to effectively use hearing aids, cochlear implants can provide great benefit, although they do not restore normal hearing. Cochlear implants stimulate the hearing nerve directly with electrical currents from a set of electrodes surgically implanted into the inner ear (cochlea). Although cochlear implants are a great success, a wide range in speech perception outcomes are observed.
The aim of this programme of research is to reduce the variability in performance as well as increasing the levels of speech recognition achieved by all. We propose to achieve this by using a special machine to measure brain activity in response to sound for cochlear implant users. This technique is used routinely in clinical practice and involves wearing a special hat to make the recordings. We will use this method to record responses at different parts of the hearing system between cochlea and brain. By understanding the relationship between these responses and speech understanding it will help us to appreciate the importance of different stages in the hearing pathway. These measures will allow us to observe the brain changes that take place once cochlear implants are switched on. We will define 'biomarkers' that can be used by clinicians to guide implant fitting and rehabilitation. A biomarker is an objective measurement of typical changes in the body.
We will develop guidance for adjusting the ways that sounds are sent through the cochlear implant or for switching off electrodes. For those with bilateral cochlear implants we will also develop guidelines for adjusting the implants to make the sounds more similar in each ear to improve the way that the ears work together. This research will be conducted with both adults and children to fully understand how people hear with a cochlear implant.
The aim of this programme of research is to reduce the variability in performance as well as increasing the levels of speech recognition achieved by all. We propose to achieve this by using a special machine to measure brain activity in response to sound for cochlear implant users. This technique is used routinely in clinical practice and involves wearing a special hat to make the recordings. We will use this method to record responses at different parts of the hearing system between cochlea and brain. By understanding the relationship between these responses and speech understanding it will help us to appreciate the importance of different stages in the hearing pathway. These measures will allow us to observe the brain changes that take place once cochlear implants are switched on. We will define 'biomarkers' that can be used by clinicians to guide implant fitting and rehabilitation. A biomarker is an objective measurement of typical changes in the body.
We will develop guidance for adjusting the ways that sounds are sent through the cochlear implant or for switching off electrodes. For those with bilateral cochlear implants we will also develop guidelines for adjusting the implants to make the sounds more similar in each ear to improve the way that the ears work together. This research will be conducted with both adults and children to fully understand how people hear with a cochlear implant.
Technical Summary
There are over 700,000 severe-to-profound hearing-impaired listeners with cochlear implants (CIs) worldwide and over 15,000 in the UK. CIs are life changing devices that restore hearing and give many individuals the opportunity to function in the hearing world. They provide a useable signal to the auditory system that enables young children to dramatically improve their developmental trajectory for speech and language acquisition. Despite being considered one of the most successful interventions in modern medicine, there is a huge amount of variation in CI hearing outcomes, in both child and adult CI users.
The aim of this research is to reduce variability in outcomes, and to improve performance to be closer to normal hearing even in highly performing individuals. To do so, we explore four man themes: variations in cortical responses to CI stimulation, how they relate to functional measures of hearing, and their shaping by ascending auditory inputs; brain adaptation and cross-modal reorganization following implant activation; evaluating if re-mapping based on cortical responses improves functional outcomes of hearing; and measuring neural indicators of binaural integration from bilateral implants.
We will employ electrophysiology techniques using electroencephalography (EEG) to objectively determine auditory capabilities of cochlear implant (CI) users and brain changes occurring following implant activation. Specific measures will look at electrode discrimination, within-channel modulation rate discrimination and between ear inter-aural time differences, inter-aural level differences. We will make use of responses to guide CI re-mapping. We will relate responses with psychophysical scores and speech perception data.
The findings will provide clinicians with tools to inform re-mapping and training interventions and, with the support of industry the implementation of important procedures, into clinical practice.
The aim of this research is to reduce variability in outcomes, and to improve performance to be closer to normal hearing even in highly performing individuals. To do so, we explore four man themes: variations in cortical responses to CI stimulation, how they relate to functional measures of hearing, and their shaping by ascending auditory inputs; brain adaptation and cross-modal reorganization following implant activation; evaluating if re-mapping based on cortical responses improves functional outcomes of hearing; and measuring neural indicators of binaural integration from bilateral implants.
We will employ electrophysiology techniques using electroencephalography (EEG) to objectively determine auditory capabilities of cochlear implant (CI) users and brain changes occurring following implant activation. Specific measures will look at electrode discrimination, within-channel modulation rate discrimination and between ear inter-aural time differences, inter-aural level differences. We will make use of responses to guide CI re-mapping. We will relate responses with psychophysical scores and speech perception data.
The findings will provide clinicians with tools to inform re-mapping and training interventions and, with the support of industry the implementation of important procedures, into clinical practice.
Planned Impact
Who will benefit?
In the short term (over the first two years) the project will have a major impact on academic researchers investigating the structure and development of cochlear implant listening in children and adults. Even at this early stage, clinicians working with both children and adults using CIs will be aware of the emerging data and its significance. Clinicians will be invited to comment on the data in the context of child and adult CI provision. Over the mid-term of the project, there will be sufficient data for formal consultations with CI centres about the practicalities of the new electrophysiology techniques proposed, alongside initial thoughts on intervention programs that might benefit CI provision. At this stage, initial consultation with the manufacturers of the electrophysiological equipment used in the study will be made, with a view for slimming down the costs and complexity in order to be viable in NHS \ clinical settings. For a small group of CI users, some piloting of an Intervention program will have started: as such, these CI users will have been identified as needing attention and will have at least embarked on a program of intervention. During the final two years of the project, we expect feedback from other research organisations that have followed up and extended our initial findings. We expect further development of intervention programs based in clinics, and will invite comment from both CI clinicians and Speech and Language Therapists. Our intervention programs will have developed sufficiently to consult with the manufacturers of CIs. We expect that changes to the provision of the clinical software supplied to CI centres can be made. The end-product of this research effort are the CI users themselves, both adult and children, and the benefit is expected to be greatest in those with the poorest speech perception abilities.
How will they benefit?
Academic researchers will keenly anticipate the outcomes of the research as it provides much missing information about the cortical organisation of auditory information post CI activation. While some knowledge has been gained from behavioural measures in adult CI implantees, tools for exploring objective measures of cortical organisation are absent. These same tools can be used for exploring child auditory maturation post CI activation. While CI clinicians are often able to perform behavioural speech tests of CI performance, they will benefit enormously from the electrophysiological tools provided by the project for measuring objective speech performance. The commercial interests: cochlear implant companies (e.g. Advanced Bionics, Cochlear Corp., MedEl) and electrophysiology equipment companies (e.g. BioSemi)) will be interested in refining their products in light of the study outcomes. Finally, assuming our intervention programs are at least partially successful, child and adult CI users (together with related carer's of CI users, including parents and teachers) will benefit from better speech performance, compared to their performance before the project.
In the short term (over the first two years) the project will have a major impact on academic researchers investigating the structure and development of cochlear implant listening in children and adults. Even at this early stage, clinicians working with both children and adults using CIs will be aware of the emerging data and its significance. Clinicians will be invited to comment on the data in the context of child and adult CI provision. Over the mid-term of the project, there will be sufficient data for formal consultations with CI centres about the practicalities of the new electrophysiology techniques proposed, alongside initial thoughts on intervention programs that might benefit CI provision. At this stage, initial consultation with the manufacturers of the electrophysiological equipment used in the study will be made, with a view for slimming down the costs and complexity in order to be viable in NHS \ clinical settings. For a small group of CI users, some piloting of an Intervention program will have started: as such, these CI users will have been identified as needing attention and will have at least embarked on a program of intervention. During the final two years of the project, we expect feedback from other research organisations that have followed up and extended our initial findings. We expect further development of intervention programs based in clinics, and will invite comment from both CI clinicians and Speech and Language Therapists. Our intervention programs will have developed sufficiently to consult with the manufacturers of CIs. We expect that changes to the provision of the clinical software supplied to CI centres can be made. The end-product of this research effort are the CI users themselves, both adult and children, and the benefit is expected to be greatest in those with the poorest speech perception abilities.
How will they benefit?
Academic researchers will keenly anticipate the outcomes of the research as it provides much missing information about the cortical organisation of auditory information post CI activation. While some knowledge has been gained from behavioural measures in adult CI implantees, tools for exploring objective measures of cortical organisation are absent. These same tools can be used for exploring child auditory maturation post CI activation. While CI clinicians are often able to perform behavioural speech tests of CI performance, they will benefit enormously from the electrophysiological tools provided by the project for measuring objective speech performance. The commercial interests: cochlear implant companies (e.g. Advanced Bionics, Cochlear Corp., MedEl) and electrophysiology equipment companies (e.g. BioSemi)) will be interested in refining their products in light of the study outcomes. Finally, assuming our intervention programs are at least partially successful, child and adult CI users (together with related carer's of CI users, including parents and teachers) will benefit from better speech performance, compared to their performance before the project.
Publications
Hu H
(2023)
A model framework for simulating spatial hearing of bilateral cochlear implant users
in Acta Acustica
Parmar BJ
(2022)
Factors Affecting the Use of Speech Testing in Adult Audiology.
in American journal of audiology
Vickers D
(2023)
Medical Safety and Device Reliability of Active Transcutaneous Middle Ear and Bone Conducting Implants: A Long-Term Multi-Centre Observational Study
in Applied Sciences
Saleh SM
(2023)
Test-Retest Reliability of the Coordinate Response Measure in Adults with Normal Hearing or Cochlear Implants.
in Audiology & neuro-otology
Rayes H
(2021)
The Development of a Paediatric Phoneme Discrimination Test for Arabic Phonemic Contrasts.
in Audiology research
Fullerton AM
(2023)
Cross-modal functional connectivity supports speech understanding in cochlear implant users.
in Cerebral cortex (New York, N.Y. : 1991)
Mathew R
(2021)
Assessment of the cochlear implant pathway for newborn hearing screening referrals.
in Cochlear implants international
Van Der Straaten TFK
(2021)
Selection Criteria for Cochlear Implantation in the United Kingdom and Flanders: Toward a Less Restrictive Standard.
in Ear and hearing
Vickers D
(2021)
Involving Children and Teenagers With Bilateral Cochlear Implants in the Design of the BEARS (Both EARS) Virtual Reality Training Suite Improves Personalization.
in Frontiers in digital health
Koohi N
(2019)
A Hearing Screening Protocol for Stroke Patients: An Exploratory Study.
in Frontiers in neurology
Calcus A
(2022)
Simultaneous subcortical and cortical electrophysiological recordings of spectro-temporal processing in humans.
in Frontiers in neurology
Salorio-Corbetto M
(2022)
Evaluating Spatial Hearing Using a Dual-Task Approach in a Virtual-Acoustics Environment.
in Frontiers in neuroscience
Hu H
(2022)
Spectral and binaural loudness summation of equally loud narrowband signals in single-sided-deafness and bilateral cochlear implant users
in Frontiers in Neuroscience
Undurraga JA
(2021)
Neural encoding of spectro-temporal cues at slow and near speech-rate in cochlear implant users.
in Hearing research
Zedan A
(2022)
Modelling speech reception thresholds and their improvements due to spatial noise reduction algorithms in bimodal cochlear implant users.
in Hearing research
De Kerangal M
(2021)
The effect of healthy aging on change detection and sensitivity to predictable structure in crowded acoustic scenes.
in Hearing research
Brochier T
(2022)
From Microphone to Phoneme: An End-to-End Computational Neural Model for Predicting Speech Perception With Cochlear Implants
in IEEE Transactions on Biomedical Engineering
Mehta K
(2020)
Clinicians' views of using cortical auditory evoked potentials (CAEP) in the permanent childhood hearing impairment patient pathway.
in International journal of audiology
Parmar BJ
(2022)
Experienced hearing aid users' perspectives of assessment and communication within audiology: a qualitative study using digital methods.
in International journal of audiology
Van Der Straaten TFK
(2023)
Diagnostic value of preoperative measures in selecting post-lingually deafened candidates for cochlear implantation - a different approach.
in International journal of audiology
Holland Brown T
(2023)
Speech discrimination and word identification with a consumer-level bone-conduction headset and remote microphone for children with normal hearing.
in International journal of audiology
Jürgens T
(2023)
Spatial speech-in-noise performance in simulated single-sided deaf and bimodal cochlear implant users in comparison with real patients.
in International journal of audiology
Nunn TB
(2019)
A systematic review of the impact of adjusting input dynamic range (IDR), electrical threshold (T) level and rate of stimulation on speech perception ability in cochlear implant users.
in International journal of audiology
Mehta K
(2019)
A qualitative review of parents' perspectives on the value of CAEP recording in influencing their acceptance of hearing devices for their child
in International Journal of Audiology
Guideline Title | Cochlear implants for children and adults with severe to profound deafness [ID1469] - Single Technology Appraisal |
Description | Amendment to NICE guidelines on candidacy criteria for cochlear implants in the UK |
Geographic Reach | National |
Policy Influence Type | Citation in clinical guidelines |
Impact | NICE have reviewed guidance and changed the audiometric thresholds for criteria from 90 dB HL to 80 dB HL or greater as recommended in this research. As this was the only paediatric cochlear implant candidacy research available it was extremely influential in guiding the change in guidance on audiometric cut off values. I enclose the committee papers at this stage because the final report has not yet been published in full because there is currently a period for appeal. |
URL | https://www.nice.org.uk/guidance/gid-ta10362/documents/committee-papers |
Description | Cambridge-Tel Aviv University Strategic Partnership to Optimize Development and Outcomes for Children with Deafness |
Amount | £6,600 (GBP) |
Funding ID | : UIIUSCP-1297200316 |
Organisation | British Council |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 03/2020 |
End | 08/2022 |
Description | Realising the Potential of Cochlear Implants - Scientific Meeting Flexigrant application |
Amount | £40,000 (GBP) |
Organisation | The Royal Society |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 09/2019 |
End | 06/2020 |
Title | Electrophysiological technique for understanding envelope rate discrimination in cochlear implant users |
Description | Using the auditory change complex it can provide objective information about discrimination of envelope cues and speech cues. |
Type Of Material | Physiological assessment or outcome measure |
Year Produced | 2020 |
Provided To Others? | Yes |
Impact | It is being adapted for clinical use to help map cochlear implant sound processors for paediatric cochlear implant users. There is a great deal of interest from Interacoustics. |
Title | SSiN-VA outcomes for twelve normal-hearing participants |
Description | Raw data from normal hearing listeners to validate the Spatial Speech in Noise - Virtual Acoustics test. |
Type Of Material | Database/Collection of data |
Year Produced | 2022 |
Provided To Others? | Yes |
Impact | Evidence that the virtual implementation emulates a spatial testing set up |
URL | https://www.repository.cam.ac.uk/handle/1810/332842 |
Description | Binaural measurement development and modelling |
Organisation | Carl von Ossietzky University of Oldenburg |
Department | Medical Physics Group Oldenburg |
Country | Germany |
Sector | Academic/University |
PI Contribution | Meetings and discussions and we are arranging a meeting to compare results of different measurements. |
Collaborator Contribution | Piloting bilateral techniques and visiting our lab for meetings |
Impact | Still finalising the measurments |
Start Year | 2019 |
Description | Macquarie University Electrophysiology Exchange and Training Partnership |
Organisation | Macquarie University |
Department | Department of Linguistics |
Country | Australia |
Sector | Academic/University |
PI Contribution | Piloting and comparing approaches for cortical measurements and advising on shielded headphone calibration. |
Collaborator Contribution | Visit to help set up the lab and help establish initial measurements and provide a programme of training. |
Impact | An article in the proceedings from the conference, International Congress on Acoustics. |
Start Year | 2019 |
Title | Pulsatile Cochlear Implant Vocoder v 1.0.1 |
Description | Pulsatile vocoder for simulating cochlear implant processing |
Type Of Technology | Webtool/Application |
Year Produced | 2019 |
Open Source License? | Yes |
Impact | Improved use of vocoder. Quality electrodograms that accurately reflect cochlear implant processing. |
URL | https://doi.org/10.5281/zenodo.3234499 |
Description | Adult Cochlear Implant Advocacy Meeting |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Patients, carers and/or patient groups |
Results and Impact | This was an advocacy meeting organised by a company to engage with adult cochlear implant users to enhance their engagement in the field. My role was to represent researchers to discuss how we can ensure that research activities meet the needs of the population. Many different areas were discussed at the event. |
Year(s) Of Engagement Activity | 2020 |
URL | https://ciicanet.org/ |
Description | BrainBus - Neuroscience research activities for primary school children |
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 | Marina Salorio-Corbetto volunteered as a demonstrator with BrainBus, an MRC-CBU initiative promoting scientific curiosity in primary-school-aged children. We wanted to represent our research on brain activity relating to hearing in the BrainBus programme and form links with other Cambridge Hearing Group researchers and other neuroscientists as well as engaging underprivileged children in science. Activities consist of school visits where children perform Neuroscience experiments, analyse the outcomes, and discuss the results. The experimental sessions were followed by a discussion about the brain where children are presented with age-appropriate content and hands-on material (e.g. 3-D printed brains), and are encouraged to ask questions. |
Year(s) Of Engagement Activity | 2019 |
URL | https://www.mrc-cbu.cam.ac.uk/brain-bus/?fbclid=IwAR0SY3H9g1ilE_5OL7mJm5vIRMSDm2Ru-44UXt4ZDx1Igc67DA... |
Description | Edited a special issue on computational audiology for ENT and Audiology News |
Form Of Engagement Activity | A magazine, newsletter or online publication |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | A compilation of articles to demonstrate the wide range in advances in computational audiences: Editorial: The Changing World of Computational Audiology by Deborah Vickers and Lorenzo Picinali 1) Personal perspective of a hearing aid user: In conversation with Alistair Cruickshank Interviewed by Lorenzo Picinali and Deborah Vickers 2) Wisdom and the cochlear implant clinician by Helen Cullington 3) Can the audiology clinic benefit from advances in virtual reality? by François Patou 4) Hearables: in-ear sensing devices for recording of physiological signals by Colver Ken Howe Ne, Jameel Muzaffar and Manohar Bance 5) Machine learning to support audiology by Jessica JM Monaghan and David Allen |
Year(s) Of Engagement Activity | 2022 |
URL | https://www.entandaudiologynews.com/news/post/audiology-in-this-issue-the-changing-world-of-computat... |
Description | Realising the Potential of Cochlear Implants |
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 to draw together researchers, clinicians and industry to share ideas to help improve outcomes for cochlear implant users. |
Year(s) Of Engagement Activity | 2022 |
URL | https://royalsociety.org/science-events-and-lectures/2022/06/cochlear-implants/#:~:text=Cochlear%20i... |
Description | Royal Institution Family Fun Day |
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 | We were given a room to explain cochlear implants to the general public and demonstrate our ongoing development of intervention and assessment tools. |
Year(s) Of Engagement Activity | 2023 |
URL | https://www.rigb.org/learning/family-fun-days |