Previous studies have shown that most patients with functional oropharyngeal dysphagia could be quickly, safely and accurately recognized by using a clinical bedside method developed by the investigative team as the volume-viscosity swallow test (V-VST) that systematically evaluates the main clinical signs and symptoms of safety and efficacy of swallowing and monitors pulse oximetry to improve the detection of patients with silent aspirations.The aim of this study is to validate this test for persons suspected of having swallowing impairment, using a new thickener, with respect to the Videofluoroscopy (VFS) method (treated as the gold standard).

Inclusion Criteria:

• History of swallowing difficulties associated with aging and/or neurological diseases including patients with: -neurodegenerative diseases. -non-progressive neurological diseases including stroke. -older patients including nursing home patients.
• Age > 18 y
• Ability to give informed consent

Exclusion Criteria:

• Patients suffering idiosyncratic phenomena or who are allergic to any medication, especially iodinated contrast media
• Patients suffering major respiratory disease or undergoing any type of surgery in the three months prior to the study
• Patients with a background of alcohol dependence or other drug dependence
• Patient who cannot be expected to comply with treatment
• Patient currently participating or having participated in another clinical trial during the last 4 weeks prior to the beginning of this study

120 Patients suspected of having symptoms of swallowing impairment will be enrolled in the study as well as 14 healthy volunteers