Coordination between Posture and Phonation in Vocal Effort Behavior

International audienceIntroduction: Postural aspects of vocal effort are unusually described in the literature whereas they are extensively managed in speech therapy. Objectives: This study aims to determine whether body movement is a side-effect of vocal effort or an integrant part of global communication effort behaviour. The answer to this question is mainly based on the correlations between the movement and the phonation.Design: This experimental study involved healthy subjects. They had to communicate to a listener during exposure to three situations where the environmental obstacles were increasing.Results: Vocal parameters such as sound pressure level, fundamental frequency, closed quotient and words duration all increased with increasing difficulty of communication (ie. increasing vocal effort). All body segments movement increased their amplitude and duration with increasing vocal effort. Vocal and kinematic characteristics were significantly correlated.Conclusion: The close correlation of movement and vocal production during vocal effort definitely excludes that the movement is a consequence of the latter. Posture and voice are coordinated in the action of communication and each body segment seems to play a different role in the vocal effort behaviour