Silent aspiration and swallowing physiology after radiotherapy in patients with nasopharyngeal carcinoma

Background. There is a paucity of knowledge on dysphagia in patients with nasopharyngeal carcinoma postradiotherapy (NPC post‐RT). The purpose of this study was to establish silent aspiration occurrence, safe bolus consistency, and their relationship with swallowing physiology in patients with dysphagic NPC post‐RT. Methods. Eighty‐five patients with dysphagic NPC post‐RT were assessed across 4 bolus consistencies. We compared penetration‐aspiration scores against 4 swallowing physiology impairments. Results. Silent aspiration occurred in 65.9% of patients with dysphagia, with 64.7% on thin fluids, 35.3% on thick fluids, 11.8% on pureed diet, and 5.9% on soft diet. Multivariate analysis of variance (MANOVA) indicated pharyngeal contraction and swallowing response had significant effect on thick fluids (p = .002), thin fluids (p = .017), and soft diet (p = .031). Conclusion. Silent aspiration of thin fluids is a common occurrence in dysphagic NPC post‐RT, with least aspiration noted on soft diet. Considering the high incidence of silent aspiration, instrumental assessment in this cohort is crucial. © 2010 Wiley Periodicals, Inc. Head Neck, 2010