Field tests of a wearable 16-channel electrotactile sensory aid in a classroom for the deaf

Abstract

Field testing of a wearable electrotactile sensory aid began in February 1985 at the Jackson Hearing Center, an oral program for deaf children in Palo Alto, CA. Six children, 3 to 8 years of age, participated in the study. Each had a profound congenital binaural sensorineural hearing loss in excess of 105 dB. The wearable sensory aid, the Tacticon model 1600, presents 16 channels of frequency information via a tactile belt worn around the abdomen. Wearing time for each child was gradually increased from half-hour daily lessons to 4 h of use per day. Environments included the classroom, outside recess with physical education activities, and field trips. Receptive training was directed at recognition of both suprasegmental and segmental features of speech. Suprasegmental features included duration, number of syllables, rhythm, and stress. Segmental features included the recognition of specific speech sounds in isolation, beginning with the Ling 5 sound test of /a/, /e/, /u/, /s/, and /sh/. The assessment procedure was conducted in three modes: (a) aided residual hearing alone, (b) aided hearing plus lipreading cues, and (c) aided hearing plus lipreading plus tactile cues from the sensory aid. The addition of tactile cues results in a significant increase in the discriminability of both suprasegmental and segmental features. The children also received experience with the sensory aid during speech training, attending to the tactile patterns resulting from different speech features such ns nasaiity, voicing, frication, and plosion, comparing their utterances with those of the teacher. Their performance indicated that the tactile feedback supported an improvement in speech production, as well as reception. [Work supported by SBIR/NIH: 2 R44 AG/NS04817.]