Diagnosis of Dysphagia

Dysphagia can be diagnosed and monitored with many different screening tools. Common to all these screening tools is the ability to differentiate patients at risk for aspiration and laryngeal penetration from those who can consume solids and/or liquids safely (Papadopolou 2013). One of the most common and initial forms of screening for dysphagia is the Bedside Swallowing Evaluation (BSE). The BSE is important in helping clinicians decide the degree of safety in oral feeding, and foresee warnings about potential complications. The BSE allows speech-language pathologists to conduct a case history interview about the patient’s nutritional and respiratory medical status, and an examination of oral motor abilities including labial, palatal, lingual, pharyngeal wall, and laryngeal muscle control; along with an assessment of swallowing (Workman and Treole 2002). Patients are diagnosed with dysphagia if the speech language pathologist performing the BSE observes signs of aspiration, such as coughing, choking, or liquid and/or food present in or around the tracheostomy stoma, limited or uncoordinated laryngeal movement, or a wet sound in vocal quality after drinking (Shem et al. 2012).

Videofluoroscopic Swallow Studies (VFSS) are considered to be the gold standard for evaluation of oropharyngeal dysphagia as it provides direct visualisation of the movement of the jaw, palate, pharynx, larynx, esophagus and tongue during the swallowing motion (Shem et al. 2012b). Videofluroscopy works by ingestion of different types of foods ranging from very liquid to solid made radiopaque with a small dose of barium sulfate, via syringe or spoon in order to measure muscle movements during swallowing (Ryu et al. 2012). Not only can it be used to diagnose the existence of dysphagia in a patient, it can also be used to determine the etiology of dysphagia and under what conditions the patient can swallow safely (Shem et al. 2012b). Dysphagia is diagnosed if a patient undergoing the VFSS presents with any of the following: pooling of the test material in pyriform sinuses/valleculae, decreased laryngeal elevation, lack of epiglottic inversion, laryngeal penetration and aspiration (Shem et al. 2012b). Not only does this assessment require specially-trained technicians, but patients who are in intensive care, unable to sit in the correct position, or those with a high risk of aspiration may not be suitable to undergo VFSS (Papadopoulou et al. 2013).

The Fiberoptic Endoscopic Evaluation of Swallowing (FEES) is a widely used diagnostic procedure in exploring the swallowing process when patients are not suitable for VFSS. It is performed using a flexible laryngoscope that is fed through the nasal cavity that allows imaging of the epiglottis, sinus piriformis and arytenoid cartilages; consumption of a bolus (liquid or semi-liquid food) allows for examination of the swallowing reflex and presence of aspiration, retention and laryngeal penetration can be observed (Wolf & Meiners 2003). FEES can be performed in a sitting eating position, or for bed-ridden patients the head of the bed is raised 45 degrees or more to compensate (Papadopoulou et al. 2013). FEES is well tolerated, administrable to bed-ridden patients, and can be used repeatedly to monitor therapy progress. FEES is disadvantaged in that the oral and esophageal phase of swallowing cannot be examined; additionally, documentation and reporting of FEES can be time-consuming and difficult to complete (Hey et al. 2009).

Discussion

The majority of studies assessing the diagnosis of dysphagia in a SCI population relied on either the BSE or VFSS as their screening tools. Four studies used both measures for diagnosing dysphagia (Chaw et al. 2012, Shem et al. 2012, Shem et al. 2012b, Shem et al. 2011). The incidence of dysphagia for these studies was on average, 40%. Shem et al. (2012b) performed a novel, prospective, psychometric comparison between the BSE and VFSS, for patients recently admitted to acute care for their SCI, to determine if the BSE was as accurate as the VFSS. The sensitivity, specificity, positive predictive and negative predictive values were calculated for the BSE in reference to the VFSS. The BSE performed comparatively well with the VFSS, with a sensitivity of 100% and a specificity of 93.3%. There was only one case of a misdiagnosis of dysphagia by the BSE, which the VFSS ruled out, giving a positive predictive value of 91.7%. Importantly, the BSE was able to rule out to the same extent as the VFSS individuals not at risk of dysphagia, with a negative predictive value of 100%. The results of this study indicate that the BSE can be an excellent screening tool for dysphagia in a SCI population that performs nearly as well as the VFSS. This is important given that the VFSS is more expensive, invasive, requires patients to be seated in a certain way, and protocols for VFSS may vary from facility to facility. However, the authors found when comparing diet recommendations, the BSE did not perform nearly as well as the VFSS, with diets recommended by BSE being more stringent and limiting the amount of safe foods patients can eat. Therefore, the VFSS still has an important clinical role in determining nutrition recommendations after a dysphagia diagnosis.

Wolf and Meiners (2003), was the only study that examined FEES as a method of diagnosis for dysphagia in a SCI population. The authors used FEES to diagnose dysphagia based on five levels of swallowing dysfunction, where levels 1 and 2 indicated severe swallowing impairment, level 3 was presence of aspiration, level 4 was mild aspiration or laryngeal edema, and level 5 was no signs of laryngeal dysfunction. They found a high incidence of dysphagia of 80%; however, only 40% had severe dysphagia whereas 50% had mild dysphagia. Treatment was given to dysphagic individuals proportional to their level of swallowing impairment that included: artificial respiration, positive end expiratory pressure, tracheostomy, nasogastric tubes, and breathing exercises. FEES was useful in that it allowed for repeated administration to track patients’ treatment progress in ICU settings.

Conclusion

There is level 5 evidence (from several observational studies: Chaw et al. 2012, Shem et al. 2012, Shem et al. 2012b, Shem et al. 2011, Seidl et al. 2010, Abel, Ruf & Spahn 2004, Kirshblum et al. 1999) that VFSS and BSE are adequate measures of diagnosing dysphagia in a SCI population.

There is level 5 evidence (from four observational studies: Chaw et al. 2012, Shem et al. 2012, Shem et al. 2012b, Shem et al. 2011) that VFSS and BSE are comparable in diagnosing dysphagia in a SCI population.

There is level 5 evidence (from one observational study: Wolf and Meiers 2003) that FEES is an adequate tool to diagnose dysphagia and monitor treatment progress in a SCI population.