Evaluating tactile aids for speech perception and production by hearing-impaired adults and children

The type and degree of benefit provided by tactile aids for the hearing-impaired varies from device to device, as a function of such variables as the number of tactile transducers, type of stimulation, location of stimulation, and the nature of processing of the input acoustic waveform. In this paper the results from evaluations of tactile devices in our laboratory are discussed, to provide some insights into the amount of assistance that might be expected from the use of different tactile aids in different listening tasks. A number of perceptual tasks have been evaluated, ranging from simple detection of a stimulus to the tracking of connected speech. The results of these evaluations suggest that tactile aids, particularly multichannel devices that employ a number of tactile transducers and convey information about the spectral content of the speech signal, can be of significant benefit in speech perception. Further studies with profoundly hearing-impaired children indicate that aspects of speech production can also be improved through the use of a multichannel tactile aid, as evidenced from judgments of videotaped productions shown to teachers of the hearing-impaired. These findings suggest that even a relatively brief period of training with a tactile aid can lead to improvements in speech production by hearing-impaired children.