Abstract
This paper discusses a stiffness sensing system that can measure tongue stiffness in vivo. Considering that the global stiffness generally depends upon the thickness of tissue, we utilize the equivalent Young's modulus defined by the applied pressure divided by the tissue strain. We also introduce an index of muscle contraction by using EMG signal for judging whether the stiffness increase is caused by a muscle contraction or a disease. By using an experimental system composed of a gripper typed stiffness sensing system and an EMG sensor, we show that the equivalent tongue Young's modulus under muscle contraction is four times larger than that under no contraction.
