This is a functional test that assesses the swallowing mechanism using x-rays. Also known as a modified barium swallow study, this test is performed by a radiologist and a speech language pathologist (SLP) working in tandem. During this test, the patient is asked to swallow barium of varying consistencies while being x-rayed. The consistencies are chosen by the SLP to approximate the variety of consistencies of food that patients encounter in a normal daily diet. The x-ray images demonstrate the passage of food from the mouth through the throat, and into the esophagus. The images are evaluated for abnormalities in the swallowing mechanism by both the radiologist and the SLP. The study specifically looks for signs of aspiration, which can be seen as barium entering the windpipe. The study is purely dynamic, and is not good for examining anatomic problems such as tumors or vocal cord paralysis.