13th Annual Conference of the International Speech Communication Association

Portland, OR, USA
September 9-13, 2012

Characterizing Covert Articulation in Apraxic Speech Using Real-time MRI

Christina Hagedorn (1), Michael Proctor (1,2), Louis Goldstein (1), Maria Luisa Gorno Tempini (3), Shrikanth S. Narayanan (1,2)

(1) Department of Linguistics, University of Southern California, USA
(2) Viterbi School of Engineering, University of Southern California, USA
(3) Department of Neurology, University of California-San Francisco, USA

We aimed to test whether real-time magnetic resonance imaging (rtMRI) could be profitably employed to shed light on apraxic speech, particularly by revealing covert articulations. Our pilot data show that covert (silent) gestural intrusion errors (employing an intrinsically simple 1:1 mode of coupling) are made more frequently by the apraxic subject than by normal subjects. Further, we find that covert intrusion errors are pervasive in non-repetitious speech. We demonstrate that what is usually an acoustically silent period before the initiation of apraxic speech oftentimes contains completely covert gestures that occur frequently with multigestural segments. Further, we find that covert gestures corresponding to entire words are produced. Using rtMRI to investigate covert articulatory gestures, we are able to gather information about apraxic speech that traditional methods of transcription based on acoustic data are not at all able to capture.

Index Terms: Apraxia, speech production, covert articulation, speech error, real-time MRI, disordered speech, gestures

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Bibliographic reference.  Hagedorn, Christina / Proctor, Michael / Goldstein, Louis / Tempini, Maria Luisa Gorno / Narayanan, Shrikanth S. (2012): "Characterizing covert articulation in apraxic speech using real-time MRI", In INTERSPEECH-2012, 1051-1054.