Materials and methods

Patients diagnosed with head and neck cancer are evaluated at our oropharyngeal dysphagia unit, before and after cancer treatment. They all must give written informed consent in order to participate in this protocol. A dissociated database is employed, so there is no personal data that would identify patients. The Research Committee of Infanta Sofia University Hospital and the Ethics and Research Committee of La Paz University Hospital approved this study.

Patients must answer a screening questionnaire about oropharyngeal dysphagia. We use the Eating Assessment Tool-10, which is validated in Spanish.^{Reference Burgos, Sarto, Segurola, Romagosa, Puiggrós and Vázquez8} It is a self-administered, reliable questionnaire published by Belafsky et al. in 2008.^{Reference Belafsky, Mouadeb, Rees, Pryor, Postma and Allen9} It has 10 items that have to be scored from 0 (there is no problem) to 4 (there is a serious problem). The scores are added together, and a global score of 3 or more indicates that oropharyngeal dysphagia may be present (Figure 1).

Fig. 1. Eating Assessment Tool-10 (Spanish version).

In addition, patients must fill in a swallowing-related QoL questionnaire. We used the MD Anderson Dysphagia Inventory, which is validated in the Spanish head and neck cancer population.^{Reference Montes-Jovellar, Carrillo, Muriel, Barbera, Sanchez and Cobeta10} Chen et al. published this self-administered, psychometrically validated and reliable questionnaire in 2001.^{Reference Chen, Frankowski, Bishop-Leone, Hebert, Leyk and Lewin11} It has 20 items divided into 4 domains: the global domain (1 item) that summarises the overall QoL aspects related to swallowing; the emotional domain (6 items) that measures the emotional response to dysphagia; the functional domain (5 items) that evaluates the effect of dysphagia in daily activity; and the physical domain (8 items) that indicates the self-perception of swallowing difficulties.^{Reference Montes-Jovellar, Carrillo, Muriel, Barbera, Sanchez and Cobeta10} Each item scores from 1 (strongly agree) to 5 (strongly disagree) while the global domain is shown separately. The composite score is obtained by adding the score of the last 3 domains, calculating their mean and multiplying this by 20. So, the composite score ranges from 20 (extremely low functioning) to 100 (high functioning).^{Reference Montes-Jovellar, Carrillo, Muriel, Barbera, Sanchez and Cobeta10} A score of 80 or more indicates minimal or no swallowing problems^{Reference O'Hara, Cosway, Muirhead, Leonard, Goff and Patterson12} (Figure 2). Hutcheson et al. demonstrated that the composite score shows less variability and a more consistent performance across clinical anchors of swallowing function.^{Reference Hutcheson, Barrow, Lisec, Barringer, Gries and Lewin13} Thus, the global domain that has only 1-item is used alone in order to obtain a quick view of the patient's swallow situation. Patients are then subjected to a complete otorhinolaryngological exploration in order to find any structural and/or functional impairment.

Fig. 2. MD Anderson Dysphagia Inventory (Spanish version).

The last step is a flexible endoscopic evaluation of swallow. Patients swallow water dyed with food colouring and thickened with different amounts of food thickener according to the International Dysphagia Diet Standardization Initiative.^{Reference Badilla Ibarra14} Flexible endoscopic evaluation of swallow follows the Volume-Viscosity Swallow Test protocol.^{Reference Clavé, Arreola, Romea, Medina, Palomera and Serra-Prat15}

Flexible endoscopic evaluation of swallow data about efficiency and safety are classified according to the Dynamic Imaging Grade of Swallowing Toxicity for flexible endoscopic evaluation of swallow.^{Reference Starmer, Arrese, Langmore, Ma, Murray and Patterson16} This is developed based on the videofluoroscopic Dynamic Imaging Grade of Swallowing Toxicity™,^{Reference Hutcheson, Barrow, Barringer, Knott, Lin and Weber17} including the use of the Penetration Aspiration Scale^{Reference Rosenbek, Robbins, Roecker, Coyle and Wood18} to determine Dynamic Imaging Grade of Swallowing Toxicity-flexible endoscopic evaluation of swallow safety grades and the measurement of the percentage of pharyngeal residue to determine Dynamic Imaging Grade of Swallowing Toxicity-flexible endoscopic evaluation of swallow efficiency grades. The composite score is obtained by the interaction of the safety and efficiency grades. It ranges from 1 (mild) to 4 (life threatening) (Figure 3).

Fig. 3. Dynamic Imaging Grade of Swallowing Toxicity-flexible endoscopic evaluation of swallow (DIGEST-FEES). PAS = Penetration Aspiration Scale; Max = maximum; pen = penetration; asp = aspiration; TVF = true vocal folds

The composite oropharyngeal dysphagia features are classified according to the Dysphagia Outcome and Severity Scale.^{Reference O'Neil, Purdy, Falk and Gallo19,Reference Zarkada and Regan20} It is a 7-point rating scale, which measures oropharyngeal dysphagia severity based on videofluoroscopic swallow study. It makes recommendations for nutrition level, diet and independence^{Reference O'Neil, Purdy, Falk and Gallo19} (Table 1). Based on flexible endoscopic evaluation of swallow findings, patients receive recommendations about swallowing and diet adaptation in order to reduce the risk of aspiration and to maintain nutritional and hydration requirements. If necessary, a feeding tube is placed. Patients are sent to a speech and language pathologist if oropharyngeal dysphagia rehabilitation is required.

Table 1. Dysphagia Outcome and Severity Scale