Complexity of the Mechanism

Swallowing disorders represent a varied and often complex category of sensori-motor deficits that occur along the functional continuum of the upper aerodigestive tract. Reports of incidence and prevalence indicate that nearly one quarter of adults over the age of 50 suffer from dysphagia in the United States alone. However, these reports are likely gross under-estimates since dysphagia is a condition that accompanies multiple health issues and is not a reportable disease. What is known is that swallowing disorders have become a significant health burden to patients and caregivers, is life altering, and in many instances, life threatening.

Advancement in the diagnosis and treatment of swallowing disorders has been significant considering that the clinical science of managing swallowing was only first introduced legitimately into the literature as recently as the 1970s. Like many areas of clinical science, early studies demonstrated the safety and efficacy of interventions, yet the studies usually included small numbers of participants and are frequently underpowered. Therefore, best clinical practices emerged from patient need, demand, and the successes and failures during the patient experience. This pattern of practice emergence, albeit inevitable in most areas of clinical science, leads to ambiguity in approach to care and in interpretation of patient outcomes. We set out to determine if we could standardize the approach to swallowing assessment that would lead to unequivocal interpretation and better guide the selection and testing of treatment methods known to target the physiologic components of the swallowing mechanism. The ultimate goal for this line of clinical research is to optimize the execution of care, oral intake, health, and quality of life outcomes of dysphagic patients, regardless of the underlying medical or surgical etiology of the swallowing problem. This patient centered focus led to 5 years of NIH supported studies that produced the first standardized approach to swallowing assessment that could be practically implemented by speech-language pathology and physician teams using a videofluoroscopic (VFS) approach during routine modified barium swallowing (MBS) studies. Our team selected the MBS for study because it permits visualization of bolus flow relative to structural movement in real time throughout the swallowing continuum from mouth to stomach. Other methods of assessment, including flexible endoscopy and manometry, are also used as adjunct procedures by our team depending on the patient condition and clinical question. However, they do not provide direct visualization of the integrity and symmetry of the proposed physiologic targets of swallowing treatment or of the effects of trial interventions in real time.

The majority of studies using a VFS approach have focused on very specific physiologic questions that warrant time intensive, clinically impractical measurement methods that have not been rigorously tested for external validity. The broad application of these varied testing methods has not been embraced by the clinical community, and therefore, clinicians self-select practices based on weak levels of evidence, their patient experience, and in some cases, convenience and reimbursement patterns (Polovoy, 2012). Recent health care studies and health care reform legislation support the application of well-tested, standardized approaches to complex patient conditions to optimize outcome, minimize risk, contain cost, and inform clinicians and other stake holders regarding the effect of interventions using reliable outcome tracking methods. Recommended standards of practice must occur at 5 levels: 1) training in the behavior or medical condition, 2) diagnostic instrument and protocol for accurate data collection and ensuring patient safety, 3) method of analysis of scoring to minimize variation in interpretation, 4) selection and execution of treatment plan, and 5) reporting using well-tested approaches to presenting results (AHRQ, 2001). Reporting of treatment effectiveness has been ambiguous and insufficient for consumers and payers to fully assess the feasibility and added value of dysphagia services.

Standardized Assessment and Treatment Approach

A five-year NIH supported trial and five years of field testing led to the development and implementation of the first standardized, evidence-based method of swallowing assessment, the Modified Barium Swallowing Impairment Profile (MBSImP™�) that directs the clinician through a physiologically targeted assessment and guided treatment plan (Martin-Harris et al., 2008). The MBSImP™� includes standardized clinician training, taxonomy, protocol, interpretation, reporting, and intervention (Figure 1). Further, tools have been developed that better inform patients and caregivers regarding the nature of their swallowing problems that enhance compliance with evidence based treatment. These tools include 3D animations that mirror the patient's swallowing deficits based on data driven, physiologically accurate models that enhance patient understanding, and engage the patient and caregiver in the treatment plan.

Figure 1. Home page of the online Modified Barium Swallowing Impairment Profile (MBSImP™�), which includes standardized clinician training, taxonomy, protocol, interpretation, reporting, and intervention.

The MBSImP™� is a systematic, reliable, and valid method of scoring 17 critical physiologic components of the swallow mechanism during the administration of standardized volumes and consistencies of barium. The MBSImP™� has added to the rigor of the MBS allowing valid and reliable measures of these primary components across three functional domains (phases): oral, pharyngeal, and esophageal. Composite scores of oral and pharyngeal components are summed for calculation of Oral Total (OT) and Pharyngeal Total (PT) scores, respectively. One observation of esophageal clearance (ET) in the upright position included and has been shown to be associated with oral and pharyngeal function on the MBSImP™�. Identification of the physiologic impairment along the oropharyngeal and cervical esophageal functional continuum of swallow aid the clinician in selecting evidence based interventions known to target specific physiologic mechanisms. The example below illustrates improvement of one physiologic component of swallowing identified on the MBSImP™� ─ Component 15, Tongue Base Retraction (Figure 2). The clinician directly targets the physiologic component through an evidence-based exercise intervention leading to improved function and MBSImP™� score. 

Figure 2. Example of improvement of one physiologic component of swallowing ─ Tongue Base Retraction (Component 15) depicting VFS images. (A)Re-presents wide column of contrast or air between tongue base and pharyngeal wall, which is denoted by the red arrow. (B) Represents no contrast between tongue base and pharyngeal wall. The curved red line represents complete contact of the base of the tongue with the posterior pharyngeal wall.

Data Registry

Evidence supporting the MBSImP™� approach demonstrates its practicality, accuracy, reliability, safety, and clear link to clinical action and patient outcome. The physiologic measures obtained from the MBSImP™� assessment demonstrate significant associations with indices of patient health, nutrition, and quality of life. The PI and expert team developed a turn-key data base for entry of patient factors, environmental factors, physiologic, functional, health outcomes as an integral piece of the standardized approach. Data entry includes: MBSImP™� scores, immediate effects of swallow task and bolus characteristics, and compensatory strategies, such as postures and maneuvers. The sustained effects of therapy interventions as they impact score changes on repeat examinations are also recorded. Preliminary data shows that adaptation of this standard system leads to optimization of patient care quality, safety, efficacy, and cost (Bonilha et al., 2012). Standardized practices have facilitated inter-institutional exchange of patient data using electronic data collection, aggregation, and reporting systems. The data registry helps to adress the urgency to pursue this knowledge in view of the recent demand for provision of evidence-based practices in all aspects ofbehavioral medicine.

Modeling

Exploratory prospective collection of 267 MBS studies entered into the MBSImP™� database showed emerging, distinctive patterns of swallowing impairment across three patient groups or phenotypes (pulmonary, neurologic, and head and neck cancer) with impairment that differed in type, frequency and severity. Further, the type and severity of impairment score varied with bolus volume and viscosity. Moreover, we have demonstrated the potential to predict relationships between swallowing impairment type and external indicators of health and quality of life. For example, specific impairment types were characterized by a 7-fold increase in the odds of have a feeding tube.