Analysis of genioglossus-centered tongue muscle function groups from dynamic magnetic resonance imaging

Abstract

Internal tongue muscle functions vary in speech due to their anatomical structure differences and complex cooperative patterns. Assessment of muscle cooperative patterns and general mechanics provides insights into speech motor control and helps interpretation of clinical observations. In this work, we developed a method that revealed different function groups of all internal tongue muscles with respect to genioglossus (GG) during speech. Dynamic magnetic resonance imaging with tags was used to compute spatial and temporal muscle motion, which was deformed into a previously constructed statistical tongue atlas space. A pre-defined atlas muscle mask was used to extract motion at each muscle’s location. We used GG as a major representation of the tongue’s motion pattern and computed pattern correlation of each muscle’s motion against GG over time. Muscle function groups were determined using the value of dynamic correlation series. The data from sixteen normal controls and three post-glossectomy patients were processed, revealing that mylohyoid, geniohyoid, and digastric muscles tended to function as a separate group while most other internal muscles followed GG. However, due to patients’ post-glossectomy function loss, most of their internal muscles functioned as one unique group as a compensation strategy, providing information for further understanding of speech motor control.