Effects of audio-visual information on the intelligibility of alaryngeal speech

Background: There is minimal research on the contribution of visual information on speech intelligibility for individuals with a laryngectomy (IWL). Aims: The purpose of this project was to determine the effects of mode of presentation (audio-only, audio-visual) on alaryngeal speech intelligibility. Method: Twenty-three nave listeners were randomly presented 176 phonemically balanced sentences produced by three alaryngeal (tracheoesophageal, esophageal, electrolaryngeal) and one typical, laryngeal speaker in both audio-only and audiovisual modes of presentation. Results: Overall, results showed a small (3%) but statistically significant higher speech intelligibility score for audio-visual stimuli compared to audio-only stimuli as well as a significant interaction effect between mode of speech and mode of presentation. Within mode of speech, electrolaryngeal speech was the only mode that benefited significantly from the inclusion of visual information (10% increase). Overall intelligibility showed similar patterns both within audio-only and audio-visual modes of presentation: typical laryngeal and tracheoesophageal speech modes were significantly more intelligible than both esophageal and electrolaryngeal. Conclusions: Results suggest that listeners may benefit more from visual information from speakers with poor baseline speech intelligibility. Results also show similar intelligibility between typical, laryngeal and tracheoesophageal modes of speech. Results should be interpreted with caution, however, as only one speaker from each mode of speech was included. Further research is required to determine the nature of the increase. Learning outcomes: Readers will (1) increase their understanding of the potential impact of visual information in the perception of alaryngeal speech; (2) identify potential factors that may augment or hinder speech perception; and (3) discuss how individual modes of alaryngeal speech may be affected by audio-visual information. (C) 2009 Elsevier Inc. All rights reserved.