Vibrotactile signals can aid recognition of spectrally degraded speech signals

The potential utility of providing low-frequency portions of speech signals through vibrotactile stimulation as an aid to speech recognition by cochlear implant recipients was examined. Sixty-five young adults with normal hearing heard four-channel noise-vocoded sentences high-pass filtered above 0.25 kHz as well as those noise-vocoded sentences combined with the original signal filtered below 0.25 kHz, presented through either auditory stimulation or vibrotactile stimulation. Improved speech recognition was observed for both groups, but effects were smaller for participants in the vibrotactile group than for those in the auditory group. Future research efforts should explore ways of enhancing the vibrotactile signal.