NORMAL ADULT SWALLOWING OF LIQUID AND VISCOUS MATERIAL - SCINTIGRAPHIC DATA ON BOLUS TRANSIT AND OROPHARYNGEAL RESIDUES

Scintigraphic data are provided for 20 normal control subjects, 39-65 years of age. Each subject swallowed 10 cc of water and 10 cc of a mor e viscous material (1,100 centipoise) consisting of apple juice thicke ned with Thick-It, a commercial food thickener. The test substances we re combined with 2.5 mCi Tc-99m sulfur colloid. Scintigraphic data wer e acquired in dynamic mode for 10 sec at 25 frames/sec as the subject swallowed. Time-activity (TA) data were used to compute transit times, percentage residues in the mouth and pharynx, percent ingested, and a derived swallow efficiency score. The liquid was ingested in a single swallow by all subjects, and 9 cc was actually transferred to the eso phagus. In contrast, for the viscous material, 11/20 subjects performe d a second clearing swallow within the 10-sec interval. On the first s wallow with the viscous substance, an average of 7 cc was transferred to the esophagus. Scintigraphy offers an excellent technique for deter mining natural and preferred volumes for swallowing a variety of bolus consistencies, since it can quantify the volume of each swallow or pa rtial swallow. In this group of subjects the oral discharge time was s horter with the viscous material than with the water, but the pharynge al transit times were not significantly different for the two bolus co nsistencies. Numerical efficiency scores were lower for the viscous ma terial, indicating that such a measure is bolus dependent.