To address this problem, the investigator hypothesizes that the use of quantitative and validated approaches to measuring dysphagia will allow us to better define the heterogeneity seen in patients with dysphagia to gain insights into its prevention including the mortality risk of aspiration pneumonia our group recently demonstrated 1. Work to date using the quantitative patient-reported outcome (PRO) instruments, the Sydney Swallow Questionnaire (SSQ) and the MD Anderson Dysphagia Inventory (MDADI) has demonstrated that a reproducible signature of swallow scores can define dysphagia in irradiated HNC patients. Pilot work to date has also demonstrated that pressure flow analysis (PFA) with artificial neural network (ANN) of pharyngeal high resolution manometry and impedance (pHRMi) studies in a heterogeneous cohort of HNC patients can significantly predict for the risk of clinical aspiration and for pneumonia. This pilot study will investigate the use of serial pHRMi to identify biomechanical changes in the swallow function of HNC patients treated with radiotherapy and secondarily evaluate how the PFA may add to our current PRO-defined swallow signature.