Our goal is to design and build a new hearing aid system, which mitigates the most common complaints that hearing aid users have. These include hearing in multi-talker situations, poor sound quality, unwanted whistling resulting from feedback, and a dislike of the sound of their own voice. Current efforts, with limited success, use signal processing methods rather than restoring more closely the normal auditory function. We plan to achieve our goal by reducing to practice 3 key enabling concepts. The first is to replace the current acoustic transducer with a non-acoustic mechanical output transducer that directly actuates the tympanic membrane. This transducer, called the EarLens, floats on the tympanic membrane in a manner similar to the way a contact lens floats on the eye. The second key concept is to increase the output bandwidth of the hearing aid. The third key concept is to place a wide-bandwidth microphone in the ear canal to capture the pinna diffraction cues similar to the way the normal ear functions. Our central hypothesis is that a hearing aid that delivers amplified wide- bandwidth mechanical stimuli, directionally dependent cues, in an open canal configuration will perform better than conventional hearing aids when there are competing talkers in the background. In this phase I SBIR application, we pursue 2 specific aims.
In Specific Aim #1 the speech reception threshold as a function of bandwidth, in the presence of interfering speech from the sides, on normal and hearing-impaired subjects will be characterized. This will be done using techniques similar to those developed for the Hearing in Noise Test (HINT) under virtual auditory space conditions.
In Specific Aim #2 methods of increasing the effective gain of the EarLens transducer at high frequencies will be tested. This will be achieved by distributing the current single magnet from the center of the EarLens platform to smaller magnets on its outer portions, which reduces the limiting effects of mass inertia at high frequencies. The audiograms, from subjects with mild to moderate hearing loss, driven with different EarLens configurations will be compared. Project Narrative: Most of the 6 million hearing aid owners in the US, report various problems. Our goal is to design a high fidelity open canal hearing aid that more closely relates to normal auditory function thereby providing the brain with critical information so that it is able to segregate sounds originating from different directions and thus allow the listener to hear selectively and be able to understand desired speech from interfering speech. As an outcome of this approach, it is expected that there will be greater satisfaction with usage of the proposed hearing aid than those currently on the market. ? ? ?
