Dysphagia is a common problem in rehabilitation medicine. To accurately evaluate its disorder is crucial in managing this group patient. Videofluoroscopic examination of swallow (VFSS) is generally regarded as the “gold standard” in the assessment of oropharyngeal dysphagia, especially in the detection of laryngeal penetration or subglottic aspiration. However, its limitations are widely acknowledged. VFSS cannot be performed widely because of its radiation exposure, is a single time measure, where as aspiration may be a variable phenomenon. Moreover, VFSS may over diagnose the disorder of swallowing function since the unflavored barium could disturb deglutition ability of the patients, particularly in those who having impaired cognitive function. As a result, the researchers have sought for more reliable bedside evaluation methods to detect aspiration. Various bedside clinical evaluations such as neurological examination, water swallow test, and swallowing provocation test have been used in identifying predicting or aspiration. However, when considered against the gold standard VFSS, prediction rate for aspiration was still unsatisfactory. Seeking for more non-invasive and objective method of evaluating swallowing function is continuing by many researches.