INFLUENCE OF VERBAL AND NONVERBAL CONTEXTS ON THE SENTENCE INTELLIGIBILITY OF A SPEAKER WITH DYSARTHRIA

The influence of verbal and nonverbal contextual factors on intelligib ility was examined using sentences produced under varying conditions b y a speaker with severe flaccid dysarthria. Contextual factors include d (a) concurrent production of communication gestures, (b) predictiven ess of message content, (c) relatedness of sentences to specific situa tional contexts, and (d) prior familiarization with the speaker. Sente nces produced by the speaker were audio- and video-recorded and presen ted to 96 listeners/viewers who were assigned to three different metho ds of presentation of the stimuli: (a) audio + video, (b) audio-only, or (c) video-only conditions. Results indicated that gestures, predict iveness, and context influenced intelligibility; however, complex inte ractions were observed among these factors and methods of presentation of the stimuli. Results were interpreted in light of Lindblom's ''mut uality model,'' indicating that when signal fidelity is poor, as in th e present speaker with dysarthria, differing combinations of signal-in dependent information may be employed to enhance listener understandin g of spoken messages.