An approach to real-time magnetic resonance imaging for speech production

Abstract

Magnetic resonance imaging (MRI) has served as a valuable tool for studying static postures in speech production. Now, recent improvements in temporal resolution are making it possible to examine the dynamics of vocal-tract shaping during fluent speech using MRI. The present study uses spiral k-space acquisitions with a low flip-angle gradient echo pulse sequence on a conventional GE Signa 1.5-T CV/i scanner. This strategy allows for acquisition rates of 8-9 images per second and reconstruction rates of 20-24 images per second, making veridical movies of speech production now possible. Segmental durations, positions, and interarticulator timing can all be quantitatively evaluated. Data show clear real-time movements of the lips, tongue, and velum. Sample movies and data analysis strategies are presented.

A semi-automatic method for extracting vocal tract movements from X-ray films

“…Among them, the MRI seems promising for the future, especially with the development of dynamic MRI (e.g. Narayanan et al, 2004). In that area, the vocal tract contours are better visible and this could facilitate the marking task.…”

Determining the Relevant Criteria for Three-dimensional Vocal Tract Characterization

“…This is particularly useful in analysing the female vocal tract as it allows information about the articulators to be gathered over the singer's entire voice range. A number of studies have used MRI to investigate speech and singing, [11,14,15,16], however there is very little research using 3D imaging to specifically investigate resonance tuning in soprano voices. Although research into the effects of various articulators on speech has been ongoing for over 40 years, e.g.…”

Tracking articulator movements using orientation measurements

“…X-ray cinematography [1][2] is effective, but the radiation to the subject's head is a concern. Cine MRI can provide dynamical 3D measurement of the vocal tract but it is cumbersome and expensive [3] [4]. In contrast, the ultrasound technique is able to capture the surface of the tongue [5][6] but noise, echo artifacts and refractions may affect the results.…”