It’s about electrical signals
To understand how the neuro-Compensator hearing aid works requires a basic understanding of how we hear.
Really, it’s not about sound, it’s about electrical signals.
The brain is an organ that receives thousands and thousands of electrical stimulus from nerves.
“We don’t think of our brain like that but our senses, what we taste, what we touch, everything, this is how we sense,” said Philippe Pango, developer of the technology.
“Any sounds that come into the ear canal, the auditory nerve converts sound into an electrical impulse much like the optical nerve sending visual information.”
Pango said it was decades of research by Ian Bruce, a McMaster researcher, who developed the signal processing computer model of how a healthy ear works that provided the platform for the neuro-Compensator.
Sue Becker, another McMaster University researcher, took Bruce’s model and compared a normal hearing computer model to a damaged hearing computer model. Then she took the discrepancies between the two and came up with the idea of the neuro-Compensator computer model.
What the neuro-Compensator does is try to compensate for the damage to the auditory nerve in its transmission of the signal to the brain.
The information gathered from the computer program that has analyzed the normal ear and the damaged ear is downloaded onto a microchip that is inserted into a hearing aid.
Even though they both look alike, it’s a radically different device from traditional hearing aids which merely amplify sound - increase the audio signal to the brain.
Becker theorized the neuro-Compensator could more accurately send signals of natural and therefore very complex sounds such as speech or music to the brain.
The first round of field trials appear to prove she’s right.
Sam Mok works at Vitasound , but he also wears hearing aids and he’s a musician.
He was the first person to be fitted with the neuro-Compensator and the resulting sound surprised him.
“I could finally hear the colour of (musical) tones.”
The birth of a new hearing aid design
The idea behind the new neuro-Compensator hearing aid didn’t happen overnight nor did it occur as the result of one person. It is the result of teams of researchers led by the vision of a new way to help the hearing impaired.
Sue Becker, a key researcher in the development of the technology tells the story:
In 1999 , Simon Haykin, a Professor in the Department of Electrical and Computer Engineering at McMaster University, and Becker, a professor in the
department of Psychology Neuroscience and Behaviour, met for lunch to discuss potential collaborative research topics, and agreed that hearing aid
research was an area of mutual interest, of tremendous practical importance, with an immense potential to make a valuable contribution.
They decided to form the Intelligent Hearing Aid Group, joined by several other faculty members in the department of Psychology Neuroscience and
Behaviour: auditory system experts Laurel Trainor and John Platt, and neuroplasticity expert Ron Racine.
The group applied for funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) for a Collaborative Research Opportunities (CRO) grant, which was awarded to Haykin and the Intelligent Hearing Aid team, backed by industrial support from Gennum Corp, for a three-year period.
The group worked on several different ideas for hearing aids over the intervening years. Haykin was especially interested in the famous 'Cocktail Party Problem' where hearing impaired people have difficulty sorting out sounds in a crowded, noisy room and applied his expertise in signal processing to solve it. Becker, an expert in neural computation and brain modelling, was interested in the neural basis of hearing loss and how to apply neural modelling techniques to hearing aid design. This led Becker to propose the initial design of the neuro-Compensator, an idea that is now being commercialized in partnership with Vitasound Inc. The neuro-Compensator employs a cochlear model to simulate a given person's pattern of hearing loss. Using the cochlear model, the neuro-Compensator can measure how well it is correcting for the person's hearing loss. It can then be fine-tuned until it obtains the optimal hearing aid settings that would restore a more normal pattern of neural activity in the hearing impaired person's auditory system. McMaster's Ian Bruce, the developer of the cochlear model that is so critical to the success of the neuro-Compensator, joined the Department of Electrical and Computer Engineering, and became part of the Intelligent Hearing Aid group.
In order to translate the idea of the neuro-Compensator into a working system, an initial computer software implementation of the neuro-Compensator was developed by Jeff Bondy, a graduate student in Electrical and Computer Engineering, working under the supervision of Haykin, Becker and Bruce.
Jeff's work demonstrated in computer simulations that the idea could work in principle, and resulted in a paper published in the journal Signal Processing (Bondy, J., Becker, S., Bruce, I., Trainor, L. and Haykin. S. (2004). A novel signal-processing strategy for hearing-aid design: NeuroCompensation. Signal Processing 84(7):1239-1253.)
Subsequent developments by Zhe Chen, another Electrical and Computer Engineering graduate student, resulted in an improved version of the neuro-Compensator. These results were published in an article in the journal Neural Computation (Chen, Z., Becker, S., Bondy, J., Bruce, I.C. and Haykin, S. (2005), A novel model-based hearing compensation design using a gradient-free optimization method. Neural Computation
17(12):2648-2671).
The Intelligent Hearing Aid Group also was awarded a US Patent for the design of an intelligent hearing aid system that included the neuro-Compensator and several other components (Haykin, S., Becker, S., Bruce,
I., Bondy, J., Trainor, L. and Racine, R.J. (2005), Binaural Adaptive Hearing System. UNITED STATES Patent Application No. 10/733,451, March 31, 2005 under publication no. US-2005-0069162-A1).
The development of the neuro-Compensator might have ended with the publication of the two theoretical articles in the scientific journals, if it wasn't for
the foresight of Philippe Pango, who had worked at Gennum Corp. for many years as an audio engineer in its hearing aid division. Philippe knew about the neuro-Compensator through Gennum's interaction with the McMaster Team, and believed that the idea had the potential for commercialization. With the blessing and support of Gennum, Philippe decided to strike out on his own and
start his own company, Cayce Medical Corp. He contacted the McMaster team, and received enthusiastic support to continue the development of the neuro-Compensator with the goal of translating it into a consumer product.
With Pango's company Cayce Medical as an industrial partner, Becker applied for a market readiness grant from the Ontario Centres of Excellence (OCE). The OCE grant enabled Becker to hire Timothy Zely, a graduate of McMaster's Biomedical Engineering program. Timothy had excellent qualifications for this job, as he had already spent a summer working on cochlear models in Ian Bruce's lab. Working closely with Becker and Pango on a daily basis for a full year, and with frequent consultations with Bruce, Zely took the state of the neuro-Compensator to a whole new level. He proved to be much more than an excellent developer, but also a creative thinker, who made numerous innovative contributions to the final design.
Meanwhile, Pango was pursuing a partnership with several other former Gennum audio experts, and they joined forces to form a new company,
Vitasound Inc. Zely's promising simulation results helped to convince the Vitasound team of the potential for the neuro-Compensator to make a real
difference, and to correct the hearing loss in ways that traditional hearing aids simply cannot do.
- Sue Becker, McMaster University
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