Most caregivers do not know the influence of improper positioning therefore subjects suffer from possible choking risks. The aims of this study were to investigate the timing and coordination of swallowing and respiration in 4 different seat inclination angles, with liquid and bolus. A self-developed wearable device to measure the submandibular muscle surface EMG, the movement of thyroid cartilage and respiratory status of nasal cavity. This program could auto-analysis the onset and offset of duration, and the excursion and strength of thyroid cartilage will be calculated when it was moving, coordination between breathing and swallowing was also included. The results of this study would serve as the clinical guidelines for proper feeding positions for different populations and for different food contents.

Swallowing is not only an important function for life maintenance, but also for quality of life improvement. Statistics revealed that subjects with intellectual disability or multiple disabilities have problems in controlling muscle tone and maintaining posture. In such circumstances, these subjects experience problems during feeding or eating. The adjustment of seat inclination would help in feeding/eating process. However, the proper inclination angle should be evaluated by medical professionals, however, most caregivers do not know the influence of improper positioning therefore subjects suffer from possible choking risks. The aims of this study were to investigate the timing and coordination of swallowing and respiration in 4 different seat inclination angles, with liquid and bolus. In the first stage, the investigators intend to use a self-developed wearable device to measure the submandibular muscle surface EMG, the movement of thyroid cartilage and respiratory status of nasal cavity. This particular program could auto-analysis the onset and offset of duration, and the excursion and strength of thyroid cartilage will be calculated when it was moving, coordination between breathing and swallowing was also included. The measurement would be done in four seat inclination angles (5, 15, 30, 45) for each subject. The data collected between different conditions would be compared, and suggestions of ideal angles during swallowing would be made. The second stage is the design and development of a feedback-controlled seat angle adjustment device, based on the data collected. The results of this study would serve as the clinical guidelines for proper feeding positions for different populations and for different food contents. The ergonomic data would also provide references for assistive technology professionals and practitioners in device design and development.

Inclusion Criteria:

Typical-developed:

1. ages ranged from 20 to 60 years old,

People with disabilities:

1. ages ranged from 20 to 60 years old,
2. usually a need for supplementary feeding.

Exclusion criteria:

• Excluded conditions are cases of intubation and feeding, severely mentally retarded or autistic cases that cannot express comfort, cases of frequent choking, and those who have been treated with a throat tube and have a narrow throat.
• Exclude subjects who have undergone throat or nasal cavity surgery or have abnormalities in these two parts