A microminiature electromagnetic middle-ear implant hearing device

It is estimated that five hundred million people worldwide suffer from conductive as well as sensorineural hearing loss, conditions that cannot be surgically corrected in many cases. While the great majority of these patients are candidates for conventional hearing aid use, only a small percentage become users of amplification devices because of such factors as sound distortion, electroacoustic and mechanical feedback, discomfort, and cosmetic appearance. Several research teams have demonstrated the possibility of reproducing the effect of normal acoustic hearing by directly stimulating the inner ear using a magnet surgically placed in the middle ear and excited by a separate coil placed either in the outer or middle ear cavities. The paper describes the design of a transducer which embodies this same principle but is manufactured using micromachining techniques and can thus be implanted as an integrated device. Such a device could be used to restore hearing to those whose middle ear is damaged or diseased or to eliminate many of the sound transmission difficulties of conventional haring aids. The work presented demonstrates the feasibility of a microminiature actuator to provide the necessary excitation of the inner ear.