Test-Retest Repeatability of Articulatory Strategies Using Real-Time Magnetic Resonance Imaging

Real-time magnetic resonance imaging (rtMRI) provides information about the dynamic shaping of the vocal tract during speech production. This paper introduces and evaluates a method for quantifying articulatory strategies using rtMRI. The method decomposes the formation and release of a constriction in the vocal tract into the contributions of individual articulators such as the jaw, tongue, lips, and velum. The method uses an anatomically guided factor analysis and dynamical principles from the framework of Task Dynamics. We evaluated the method within a test-retest repeatability framework. We imaged healthy volunteers (n = 8, 4 females, 4 males) in two scans on the same day and quantified inter-study agreement with the intraclass correlation coefficient and mean within-subject standard deviation. The evaluation established a limit on effect size and intra-group differences in articulatory strategy which can be studied using the method.