Edward T. Auer
Lynne E. Bernstein
Ctr. for Auditory and Speech Sci., Gallaudet Univ., 800 Florida Ave., N.E., Washington, DC 20002
David C. Coulter
Coulter Assoc., Fairfax, VA 22031
Typically, studies evaluating tactile supplements to speechreading are relatively short in duration and limited to the laboratory. Results from an ongoing 10-month study of the effectiveness of four tactile devices will be presented. Two devices encode voice fundamental frequency (F0): One encodes F0 as rate of vibration of a single solenoid, and the other as both rate and location of vibration on a linear array of eight solenoids. Two devices are 16-channel vibrotactile vocoders: One encodes wideband speech spectral information, and the other encodes the F2 range of frequencies. Subjects are adults with pre- and post-lingual profound hearing impairments and are each assigned to use a single device for the duration of the study. Some of the subjects assigned to the single channel F0 device are also using a wearable version outside the laboratory. Comparisons of the effectiveness of all four devices over long-term exposure are being conducted using both traditional performance measures and novel measures of on-line cognitive processing. To data, 10--20 percentage point improvements in identification of words in sentences have been observed with the single channel device.