Aided and unaided speech supplementation strategies: effect of alphabet cues and iconic hand gestures on dysarthric speech.

PURPOSE: This study compared the influence of speaker-implemented iconic hand gestures and alphabet cues on speech intelligibility scores and strategy helpfulness ratings for 3 adults with cerebral palsy and dysarthria who differed from one another in their overall motor abilities.

METHOD: A total of 144 listeners (48 per speaker) orthographically transcribed sentences spoken with alphabet cues (aided), iconic hand gestures (unaided), and a habitual speech control condition; scores were compared within audio-visual and audio-only listening formats.

RESULTS

When listeners were presented with simultaneous audio and visual information, both alphabet cues and hand gestures resulted in higher intelligibility scores and higher helpfulness ratings than the no-cues control condition for each of the 3 speakers. When listeners were presented with only the audio signal, alphabet cues and gestures again resulted in higher intelligibility scores than no cues for 2 of the 3 speakers. Temporal acoustic analyses showed that alphabet cues had consistent effects on speech production, including reduced speech rate, reduced articulation rate, and increased frequency and duration of pauses. Findings for gestures were less consistent, with marked differences noted among speakers.

CONCLUSIONS

Results illustrate that individual differences play an important role in the value of supplemental augmentative and alternative communication strategies and that aided and unaided strategies can have similar positive effects on the communication of speakers with global motor impairment.