Discrimination of synthetic vowels by using tactile vocoder and a comparison with that of an eight channel cochlear implant

A test for vowel discrimination was carried out using a fingertip tactile vocoder, and the results were compared with those of an 8-channel cochlear implant. The ability to discriminate synthetic vowels was evaluated as a function of the number of channels. From experimental results, the discrimination ability with the 8-channel tactile vocoder was almost the same as that with the 16-channel device, but the ability sharply decreased when the number of channels was less than eight. The ability of the 8-channel tactile vocoder is expected to be better than that of the 8-channel cochlear implant, because vowel discrimination is degraded by a phenomenon known as current spreading in the case of cochlear stimulation.<>