Community Research and Development Information Service - CORDIS



Project ID: 311469
Funded under: FP7-IDEAS-ERC
Country: Germany

Final Report Summary - LASERHEARINGAIDS (Laser: driving force for a new generation of hearing aids)

The results of this proposal present an unconventional method for the stimulation of the outer and middle ear that may change the current concept of hearing aids. Photons of the visible light are known to activate the visual sensory cells through photoreceptors. However, when the so-called stress-confinement condition is fulfilled, laser light can induce an acoustic signal through an opto-acoustic effect. We previously demonstrated that these light induced sound waves, the optoacoustic waves, can be used to activate the inner ear, the cochlea. Unexpectedly, we found that not just the
inner ear but also the middle and outer ear are responsive to laser pulses. Therefore, laser pulses seem to have a great potential as a new stimulation method for hearing impaired patients. However, simple activation of the auditory system is not a sufficient therapy in hearing impaired people. A controlled frequency specific activation of the complete audible frequency spectrum is mandatory to make speech and complex sounds of daily life perceptible and intelligible. The frequency of the generated optoacoustic wave is dependent on the laser pulse -length, -color, -energy and the physical properties of the irradiated structure. Using the current technology it is not possible to switch between different laser sources within the duration of one word. Thus, a monochrome stimulation method is currently the only available option. Therefore, the overall objective of this project was to establish methods for frequency specific activation of the complete audible spectrum using monochrome laser pulses. The frequency modulation is a well-known process in physics that has to be validly proven for biological systems as well. With the ERC funding we were able to successfully develop a novel technique for light pulse amplitude modulation providing the basis for a novel non-contact stimulation method of the hearing system. We demonstrated that this light induced activation of the central auditory system is similar to the physiological sound induced activation pattern.

If the ongoing biocompatibility studies are successful, this method / technique might revolutionize the implantable and non-implantable hearing aids by replacing the speaker or the sound transducer (force mass transducer, the Bone Anchored Hearing Aid screw) with the non-contact and focused laser pulses. We expect that the development of these novel stimulation-strategy and stimulation-devices will ameliorate patients’ quality of life by significantly improving their aided hearing and comfort using the hearing device as well as reducing medical health care expenses determined through device related complications. Additionally, the results of the project could also be used for developing new treatment strategies for other hearing related pathologies like tinnitus as well as for research purposes.

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