Optimised round window prosthesis design simultaneously induces cochlea excitation and relieves pressure.
Lead Research Organisation:
University of Brighton
Department Name: Sch of Pharmacy & Biomolecular Sciences
Abstract
Aims
Finding an optimal design of a prosthesis which simultaneous stimulates the cochlear and relieves pressure through the round window.
Auditory rehabilitation is limited and the results of hearing prosthesis surgery vary depending on the patient and condition. The complications with conventional hearing aids, when treating conductive hearing loss, are sound quality, background noise and high amplitude acoustic feedback. The use of an electromagnetic or floating mass device is a 'non-acoustic' method of auditory rehabilitation and will help eliminate the issues with conventional hearing aids. Acoustic feedback will be reduced or eliminated as the transmission is magnetic, or electrical, and not acoustic energy, sound quality will be improved as there is lower signal degradation due to direct inner ear transmission and the implantable device bypasses the ear canal reducing risks of infection or blockage.
In this research, we will use a novel method of cochlea excitation which could provide the science to engineer a commercially used auditory prosthesis that offers an improved level of audition for mild or profoundly deaf individuals. We will design a new device which is optimised to be an effective pressure shunt but also generates a pressure wave sufficient enough to re-establish cochlea function with a sensitivity of that of conventional acoustic stimulation
Methods
Anaesthetized guinea pigs will be used to measure otoacoustic emissions generated by the inner ear during cochlea excitation via RW prosthesis displacement. Guinea pig heart rate will be measured using two electrodes placed on both sides of the thorax. Artificial respiration via tracheotomization will be in used ensuring sufficient respiration and core body temperature will be maintained at 38 degrees celsius using a heated blanket and head holder. The animal will be placed in a head holder and the middle ear cavity opened to expose the RW. Compound action potentials of the auditory nerve will be measured at the cochlea bony ridge in the proximity of the RW membrane using a Teflon-coated silver wire. Shapes and diameters of the displacing probe will be altered to increase or decrease RW occlusion. The probe will be driven using a magnetic field creating by alternating current through a surrounding two-turned copper wire, 0.15 mm in diameter, or electrically. A closed acoustic system will deliver acoustic stimulation to the tympanic membrane by using two Bruel and Kjaer 4134 half inch microphones for tones and a single Bruel and Kjaer 4133 half inch microphone for monitoring sound pressure at the tympanum. The closed system will be calibrated for frequencies between 1-50 kHz. The microphones are to be coupled to the ear canal via 1cm long, 4mm diameter tubes to a conical speculum with the 1mm diameter opening placed at the tympanum. Probef displacement will be measured using a displacement-sensitive laser diode interferometer. The laser beam will be focused centrally onto the exposed probe.
Finding an optimal design of a prosthesis which simultaneous stimulates the cochlear and relieves pressure through the round window.
Auditory rehabilitation is limited and the results of hearing prosthesis surgery vary depending on the patient and condition. The complications with conventional hearing aids, when treating conductive hearing loss, are sound quality, background noise and high amplitude acoustic feedback. The use of an electromagnetic or floating mass device is a 'non-acoustic' method of auditory rehabilitation and will help eliminate the issues with conventional hearing aids. Acoustic feedback will be reduced or eliminated as the transmission is magnetic, or electrical, and not acoustic energy, sound quality will be improved as there is lower signal degradation due to direct inner ear transmission and the implantable device bypasses the ear canal reducing risks of infection or blockage.
In this research, we will use a novel method of cochlea excitation which could provide the science to engineer a commercially used auditory prosthesis that offers an improved level of audition for mild or profoundly deaf individuals. We will design a new device which is optimised to be an effective pressure shunt but also generates a pressure wave sufficient enough to re-establish cochlea function with a sensitivity of that of conventional acoustic stimulation
Methods
Anaesthetized guinea pigs will be used to measure otoacoustic emissions generated by the inner ear during cochlea excitation via RW prosthesis displacement. Guinea pig heart rate will be measured using two electrodes placed on both sides of the thorax. Artificial respiration via tracheotomization will be in used ensuring sufficient respiration and core body temperature will be maintained at 38 degrees celsius using a heated blanket and head holder. The animal will be placed in a head holder and the middle ear cavity opened to expose the RW. Compound action potentials of the auditory nerve will be measured at the cochlea bony ridge in the proximity of the RW membrane using a Teflon-coated silver wire. Shapes and diameters of the displacing probe will be altered to increase or decrease RW occlusion. The probe will be driven using a magnetic field creating by alternating current through a surrounding two-turned copper wire, 0.15 mm in diameter, or electrically. A closed acoustic system will deliver acoustic stimulation to the tympanic membrane by using two Bruel and Kjaer 4134 half inch microphones for tones and a single Bruel and Kjaer 4133 half inch microphone for monitoring sound pressure at the tympanum. The closed system will be calibrated for frequencies between 1-50 kHz. The microphones are to be coupled to the ear canal via 1cm long, 4mm diameter tubes to a conical speculum with the 1mm diameter opening placed at the tympanum. Probef displacement will be measured using a displacement-sensitive laser diode interferometer. The laser beam will be focused centrally onto the exposed probe.
People |
ORCID iD |
| Andrei Lukashkin (Primary Supervisor) | |
| Samuel Flaherty (Student) |
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/N509607/1 | 01/10/2016 | 31/03/2023 | |||
| 1990615 | Studentship | EP/N509607/1 | 02/10/2017 | 02/04/2021 | Samuel Flaherty |
| Description | The main finding achieved is the prediction of specific dimensions for hearing devices, that utiliise the round window route, to stimulate the organ of hearing at its most efficient. The aim is to 1. Improve patient hearing rehabilitation - in the cases of conductive hearing loss 2. Aid surgeons in application of the device so that the surgery is faster, 'easier', more accurate and cheaper. |
| Exploitation Route | Companies who develop hearing devices that utilise the round window (MED-EL for example) could alter their design slightly to improve hearing rehabilitation for patients. It could save them money and improve patient satisfaction. |
| Sectors | Electronics,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology |
| Description | I would predict that our findings will be used by hearing electrical companies to modify their devices for improvement to patient hearing upon fitting. Our work could also be used by surgeons who fit hearing devices as these findings will demonstrate that certain steps in the surgery process may not be required (middle ear blocking). |
| First Year Of Impact | 2018 |
| Sector | Electronics,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology |
| Title | Mathematical model |
| Description | A mathematical model, generated from in vivo data, that will predict optimal round window coverage for the most efficient cochlear excitation. The model will first predict the readings we have collected (compound action potential thresholds when using porbes of various diameters placed on the round window). and if this is possible, can predict further arrangements. |
| Type Of Material | Model of mechanisms or symptoms - mammalian in vivo |
| Year Produced | 2019 |
| Provided To Others? | No |
| Impact | The model has not been published yet. We aim to publish by Autumn 2020. |
| Description | Round window stimulation model |
| Organisation | University of Southampton |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | Our main contributions were collecting data, carrying out tests, analysing data and writing the paper. We collected data for the award in which the collaborators are using to produce a mathematical model. We carried out tests, such as stapes displacement during stimulation, to ensure the hypothesis was correct. The data we collecting required analysing and converting into data the collaborators could utilise. We will be writing the paper with insight from the collaborators. |
| Collaborator Contribution | The collaborators have generated a mathematical model we will use in the paper for our discussion. The model will predict the optimal round window coverage for the most efficient cochlear stimulation. We have communicated and discussed the problem as a team in hope we can produce the model with acceptable Physics and assumptions. |
| Impact | We hope to generate a model that will predict an optimal coverage area of the round window for the most efficient stimulation. |
| Start Year | 2019 |