The effects of augmentative communication vs. natural speech discourse presentations on ratings of communicative effectiveness and intelligibility by typical listeners

Abstract

This study investigated the communicative effectiveness and speech intelligibility of a speaker with severely impaired speech. Adult normal subjects viewed one of four video dips depicting an individual with a speech impairment having a conversation with a normal-speaking individual in four different modes: 1) unaided speech; 2) speech combined with natural gestures; 3) speech combined with alphabet and topic supplementation; and 4) electronic voice output communication aid with no natural speech. Subjects rated communicative effectiveness on a 7-point interval scale. Subjects were also instructed to transcribe the conversation. Speech intelligibility was measured from transcription data. Results of this study indicated that there was a significant effect (p<.01) for communication modes. Percent intelligibility scores for the voice output communication aid were significantly superior (p<.01) to that of the unaided speech condition, speech combined with alphabet and topic supplementation, and speech combined with gestures. Results also indicated that the ratings of communicative effectiveness were significantly higher (p<.01) for the voice output communication aid condition than for the other modes of communication. These findings support the hypothesis that the use of a technological communication system will increase the communication success and opportunities of an individual with a severe speech impairment.