MRI vocal tract measurements of African American and White American boys
Richard J. Morris, Jeffrey R. Fitzsimmons · The Journal of the Acoustical Society of America · 1998
The purpose of this project was to use magentic resonance imaging (MRI) procedures to reveal any developmental differences between White American and Black American boys. Four boys completed the task, one 10-year-old and one 14-year-old of each racial group. Each boy was positioned on a gurney inside a General Electric 3 Tesla MRI unit. A neck coil was used to obtain all images using a gradient-echo, spin density weighted sequency with an excitation time no longer than 2 ms and a relaxation no longer than 4.9 ms; the total acquisition time per image was no longer than 327 ms. Images were taken during productions of the vowels /i/, /ɑ/, and /u/ and the words ‘‘bottle,’’ ‘‘pot,’’ ‘‘dot,’’ ‘‘tot,’’ ‘‘got,’’ and ‘‘cot.’’ Software was used to determine the oral, pharyngeal and laryngeal boundaries from the images. These boundaries were used to determine the glottal area, vocal fold length, and vocal fold thickness; the height, depth, width and volume of the pharynx; and the height, length, width and volume of the oral cavity. These data were compared with acoustic and aerodynamic data from the same subjects to provide evidence of any vocal tract differences that might underlie perceived speech differences.