Video Fluoroscopic Swallowing Exam
The video fluorographic swallowing study (VFSS), also known as a modified barium swallowing examination (MBS) is often considered the instrument of choice by the majority of practicing swallowing clinicians because it permits the visualization of bolus flow in relation to structural movement throughout the upper aero digestive tract in real-time. The VFSS also permits detection of the presence and timing of aspiration, i.e., entry of ingested material through the level of the true vocal folds into the trachea 33, 34, and assists in identifying the physiologic and often treatable cause(s) of the aspiration35-39. Further, clinicians are able to observe the effects of various bolus volumes, bolus textures, and compensatory strategies on swallowing physiology 37.
Clinicians evaluating and treating swallowing disorders use a videofluoroscopic radiology procedure to assess swallowing physiology in patients with symptoms of swallowing disorders (i.e. dysphagia) and estimate the degree of swallowing impairment from observations made during the exam. The examination usually includes the collaborative expertise of a physician (most commonly a radiologist or physiatrist and speech-language pathologist. This procedure, the modified barium swallow (MBS) examination, captures sequential video radiographic images of barium contrast- impregnated food and liquid as they are transported during the oral cavity, pharyngeal cavity, and esophagus in real time. Various volumes and textures of food and liquid are administered and clinical impressions of the presence and degree of swallowing impairment are obtained from the radiographic images 35, 38-43. Judgments are also made regarding the coordination and timing of swallowing events 1, 28, 36, 44-48. Based on these qualitative observations, critical, and sometimes life-sustaining recommendations are made regarding oral versus non-oral intake, diet type, referrals to other medical specialties, and treatment strategies that improve function or minimize the risk of aspiration 38. Despite the clinical utility of the examination, clinicians must appreciate that the patient's performance during the exam may not be entirely representative of the patient's typical eating and drinking performance. Variables such as fatigue, medications, anxiety, etc. may impact the testing results. It is imperative that clinicians observe patients during their usual eating and drinking environment to determine the external validity of the examination results and to assess the patient's ability to carry-over any learned swallowing strategies. Further, the VFSS is also used to monitor any changes in swallowing function over time during the course of swallowing treatment, progression of a disease or condition.
VFSS: AN INDIRECT SENSORY AND MOTOR EXAMINATION
Swallowing is an array of synergistic interdependent movements, initiated by a complex set of sensory inputs that generate motor responses. These motor responses create pressures and forces for propelling ingested materials through the upper aero digestive tract and simultaneously protect the upper airway. Though the VFSS does not employ direct measures of sensation and muscle strength, the following evidence suggests that trained examiners can make accurate and reliable clinical judgments regarding the presence of sensory and motor impairment. The following description of VFSS observations will be characterized as, physiologic components.