881 Swallowing Case Study

72 patients (mean age 64 years, 42 male, 30 female) with the suspicion of swallowing difficulties who were referred to videofluoroscopic examination at the University of Pittsburgh Medical Center Presbyterian (Pittsburgh, Pennsylvania) participated in this study. There were 20 participants with previous history of stroke and 52 stroke-free participants. Research consent form was obtained from all participating hospitals. Based on the speech pathologist’s diagnosis, participants were asked to swallow ($5^{\circ}C$)of different consistencies including:
• Varibar Thin Liquid, with $<5$ Centipoise (cps) consistency
• Varibar Nectar, with $\approx300$ cps consistency
• Varibar Honey, with $\approx3000$ cps consistency
• Varibar Pudding, with $\approx5000$ cps consistency
Participants performed the swallows in normal head position and in some cases in chin-tuck position. The

At the time of the study, a tri-axial accelerometer (ADXL 327, Analog Devices, Norwood, Massachusetts) was taped to the participants neck at the level of the cricoid cartilage such that the sensitive axes of the accelerometer were aligned to the anatomical anterior-posterior (A-P), superior-inferior (S-I) and medial-lateral (M-L) axes. Signals from A-P,S-I, and M-I were bandpass filtered from 0.1 to 3000 Hz with ten times amplification (model P55, Grass Technologies, Warwick, Rhode Island) prior to storage on a research computer. The voltage signals for each axis of the accelerometer were fed into a National Instruments 6210 DAQ and recorded at 20 kHz by the LabView program Signal Express (National Instruments, Austin, Texas). Concurrent with the accelerometer, bolus