Maureen Stone
Dept. of Elec. and Comput. Eng. and Dept. of Cognitive Sci., Johns Hopkins Univ., Baltimore, MD 21218
Edward P. Davis
Raulie Lo
Johns Hopkins Univ., Baltimore, MD 21218
This paper will present a new head/transducer support system for use in ultrasound imaging of tongue movement. The head is stabilized by applying gentle resistance in directions opposed to its normal directions of motion (rotation, tilt, lean). The ultrasound transducer is immobilized below the chin, separated from the skin by a compressible gelatin-like standoff that allows free jaw movement without soft tissue compression. The system images the tongue/jaw unit. Previous transducer holders have attempted to measure tongue movement relative to jaw movement by allowing the transducer to move up and down with the jaw. This is satisfactory for the tongue tip, which is dependent on jaw position. It is not satisfactory, however, for the tongue root, which moves independently of the jaw. Therefore, this system does not attempt to separate tongue and jaw behavior, but measures them as a single unit. This new support system also introduces for the first time the normalization of tongue position relative to head position. To do this, a video image of the subject's face is inserted in the image. Three marked points on a pair of eyeglasses are used to align tongue position across frames in case of head movement.