The long-term goal of this project is to help provide relief to persons whose hearing loss is so severe that they isolate themselves from normal social interactions, particularly in high-noise environments such as restaurants, it has long been recognized that such isolation may bring on mental and even physical deteriorations, but practical solutions to the problem have been limited. Hearing aids with directional microphones or high-directivity array microphones can provide 4-8 dB effective noise reduction. But it is estimated that 10% of hearing-impaired persons have a loss in the ability to understand speech in noise (signal-to-noise-ratio loss) great enough that they find it virtually impossible to carry on a conversation at a noisy dinner table or restaurant, even with a directional microphone. A well-known solution to this problem is the use of an RF microphone close to the talker's mouth, much as is used in classrooms for hearing-impaired children. This is highly effective, but permits only one-on-one conversations. On a few occasions, multiple-microphone systems (similar to that in U.S. Patent 5,966,639) have been assembled, but they have not achieved the convenience and small size required to make them attractive, and they have generally been expensive. It should now be possible to produce a multiple-microphone system with small RF microphones that clip onto the collars or blouses of three companions of the hearing impaired person (for example at a restaurant table). The hearing-impaired person will wear a small RF receiver that receives all three microphone signals and conveys the combined signal to a hearing-aid telecoil or, for those who have rejected hearing aids, directly to an insert earphone. While past development work has failed to produce a practical and inexpensive system such as described above, current integrated-circuit technology provides excellent chances of success. A crucial part of the development process will be the audiological evaluation of prototypes in real-world situations. This will be accomplished using real-world and simulated-real-world intelligibility-in-noise measures developed in the past. In addition, a subjective value rating will provide a practical check on the utility of these developments.
