Objective
The videofluoroscopic swallowing study (VFSS) has been accepted for standard method of dysphagia evaluations. But there is no research for oropharyngeal effects depending on the change of viscosity.

Method
The 10 normal subjects without dysphagia symptom or history were participated. 4 test foods were selected according to viscosity which was measured by line spread test (LST); thick semiblended diet: LST 1 cm, Yoplait: LST 2.44 cm, tomato juice: LST 3.67 cm, 35% diluted barium: LST 4.15 cm. Each foods were swallowed 3 times during VFSS. We measured oral transit time (OTT), pharyngeal delay time (PDT), pharyngeal transit time (PTT), and cricopharyngeal opening time (CPOT)

Results
There was linear correlation between OTT and LST (cm)(r=⁣0.965, P＜0.05). As the score of LST increased, PDT tended to increase linearly, but there was no statistical significance (r=0.949, P=0.509). PTT and CPOT had no significant correlation with viscosity.

Conclusion
The viscosity affected OTT and PDT. The test foods of VFSS and dysphagia diet shoud be selected by viscosity measures.