All patients are given enteral nutritional support with Intermittent Oro-esophageal Tube according to the following procedure: Before each feeding, inside and outside of the tube was cleaned with water. During feeding, the patient should maintain a semi-reclining or sitting position with mouth opened, and the tube was inserted slowly and smoothly into the upper part of the esophagus by medical staffs while the appropriate depth of intubation was checked with the calibration markings on the tube wall. The distance from the incisors to the head part of the tube should be between 22-25 cm. However, the specific depth should be evaluated based on patients' feedback and adjusted accordingly. After insertion, the tail part of the tube should be put into a container full of water and the absence of continuous bubbles indicated a successful intubation. Then, the feeding was to be conducted three times per day with 50 ml per minute and 400-600ml for each feeding.

In this study, transcranial direct current stimulation is performed using a battery-powered constant current stimulator. This device delivers the current through two electrodes immersed in saline solution. Specifically, a 50mm*50mm anodal electrode pad is placed at the center of the healthy side swallowing sensory-motor cortex of the patient. According to the positioning method of the international 10-20 electrode system, the swallowing sensory-motor cortex of the left brain is located at the midpoint between C3 and T3, while that of the right brain is located at the midpoint between C4 and T4. The cathode is placed on the opposite shoulder, using a current of 1mA, once a day, for 20 minutes each time, and 5 days a week. The instruments used for placebo patients will not have any actual effect.

The Transcranial direct current stimulation will be performed without being turned on.

The Swallowing Quality of Life Questionnaire (SWAL-QOL) is used to evaluate the impact of swallowing function on patients' quality of life. The questionnaire consists of 44 questions related to swallowing function and quality of life. Each question is answered using a 5-point rating scale. In this study, the final score is converted into a percentage. The higher scores indicate the better quality of life.

To assess the patients' depression levels, a questionnaire is used. The questionnaire consists of 9 questions related to depressive symptoms, and each question is answered using a 4-point rating scale. The total score ranges from 0 to 27, with higher scores indicating a greater tendency towards depression.

Body weight measurement of the infants was conducted by the same nurse according to the relevant standards.