Real-time ultrasound visualization of tongue movement during swallowing.

Using noninvasive real-time ultrasound, tongue movement was visualized during single swallowing in eight normal subjects and one neurologically impaired patient with dysphagia and chronic aspiration. In normals, a clearly defined muscular wave of the tongue, traveling at approximately 15 cm/sec, carried a 5-cc test water bolus posteriorly. In the patient who had 12th cranial nerve weakness, there was complete absence of normal tongue activity and no midtongue bolus formation or transmission.