It is clear that the utility of tactile aids degrades even more rapidly in the presence of noise than is the case for hearing aids. This is particularly apparent in the integration of visual and tactile cues as for example in speechreading. One reason for this is probably because many of the cues derived from tactile inputs are quite crude, depending more on temporal properties devoid of fine spectral features, than is true even for a defective auditory channel. One consequence of this is that short transient noises occurring in the background give rise to tactile stimuli that are indistinguishable from those derived from transient speech waveforms. While most existing tactile aids incorporate some form of noise suppression, the improvements obtained are modest at best, particularly as regards the transient noises which are the most deleterious. The long range goal of this project is to evolve a recently developed highly directional microphone into a format suitable for use with tactile aids in order to improve their use under noisy conditions. At present the microphone has as a major shortcoming excessive case noise. The goal of this Phase I study is to determine if the design can be replicated using small hearing aid microphone elements to obtain a small case-noise resistant package that can be conveniently worn. If successful, the design would most likely be useful for cochlear implants and hearing aids as well.
