Cleft lip and palate is the most prevalent birth defect in the United States affecting one out of every 577 births. Despite advances in surgery, it is estimated that 25-38% of children with a repaired cleft palate will continue to have hypernasal speech due to insufficient velopharyngeal closure, requiring additional surgeries. Although nasal endoscopy is frequently used to determine the type of surgery, it provides only limited views of the movements of speech. Insufficient information is available from current diagnostic technologies to visualize the location of muscles and their quantitative functional arrangement in the child. Magnetic resonance imaging (MRI) provides excellent visualization of soft tissue structures, such as muscles, but has traditionally been too slow to capture speech dynamics where complete contractions may occur in 100 ms. The current proposal develops a dynamic MRI imaging method that can image the full vocal tract in 3D+time with high spatial and high temporal resolution, achieving 166 frames per second (FPS) for the entire volume. Specifically, a dynamic speech imaging technique will be developed that is suitable for application in children aged 5-8 years old, a critical age range for re-repair of cleft palate in secondary surgical management. The technique integrates a spatiotemporal atlas that describes the mean motions across a population of healthy children for particular speech samples. The imaging technique leverages the atlas to: improve the quality of the reconstructed images, automatically label edges for quantitative analysis, and focuses the analysis on variances in motion from one subject compared to the healthy atlas. In order to examine the dependency of the population mean atlas on sex, race, and dialect, spatiotemporal atlases will be developed at three different geographical sites, with 40 healthy children ages 5-8 years old at each site, with equal numbers of both sexes and equal numbers of two races. Additionally, we will recruit 45 cleft palate patients ages 5-8 years old following cleft palate repair with and without velopharyngeal insufficiency with resulting hypernasality. We will apply our imaging technique to examine temporal characteristics of velopharyngeal muscle function, determining movement differences related to hypernasality.
The effectiveness of surgical interventions for disorders such as cleft palate could be improved by functionally relevant visualizations of the fast muscle movements during speech. Magnetic resonance imaging provides excellent visualization of underlying muscles during speech processes, but has traditionally been too slow to capture the fast motions. We develop a high spatial and high speed imaging method, that integrates spatiotemporal atlases describing normal movements, for monitoring muscle movements during speech in children with cleft palate or other speech disorders.
