Chin-tuck Against Resistance (CTAR) is a widely used training method in swallowing rehabilitation that strengthens the suprahyoid muscles, enhancing their contraction during swallowing and promoting the anterior-superior movement of the hyoid-larynx complex, thus improving the swallowing process. In 2022, Dr. Meng et al. discovered that for a patient with ineffective relaxation of the cricopharyngeal muscle, swallowing while performing CTAR significantly increased the immediate relaxation of the cricopharyngeal muscle, allowing the contrast agent to enter the esophagus smoothly. This method is named direct Chin-tuck Against Resistance (dCTAR). This study aims to evaluate the effectiveness of dCTAR in improving swallowing function, its impact on suprahyoid muscle contraction and hyoid-larynx complex movement, and further explore the relationship between tongue strength and bite force with the effectiveness of dCTAR. The study will recruit healthy subjects and dysphagia patients to investigate the relationship between tongue strength, bite force, and the effectiveness of dCTAR. This study uses ultrasound to measure changes in the cross-sectional area of the suprahyoid muscles and the elevation of the hyoid-larynx complex during swallowing before and after dCTAR; and the changes in these parameters after a total of 10 repeated CTAR training sessions over two weeks.

Inclusion Criteria:

• Age 18-90 years old
• Be conscious and able to cooperate with the inspection
• Patients with dysphagia after stroke (Functional oral intake scale, FOIS 1-6) or healthy subjects (FOIS 7)

Exclusion Criteria:

• Have a history of head and neck cancer
• Other medical history known to cause dysphagia (such as neck surgery, intubation, etc.)
• Ultrasound examination cannot be performed if there are wounds, air incisions or other structural abnormalities in the neck