The Effects of Bolus Volume and Bolus Consistency on Swallowing in Children

A number of studies have examined the effects of bolus volume and consistency on the oral and pharyngeal stages of swallowing in adults. These investigations found that the amplitude and duration of muscle activity in adults is significantly affected by these bolus variables. There is little information, however, regarding the effect of bolus volume and consistency on swallowing in children. The purpose of this study was to compile quantitative, normative data for young female children to determine the effects of various bolus volumes and consistencies on the average duration of submental and laryngeal strap muscle activity during swallowing. Surface EMG recordings were obtained from submental (SM) and laryngeal strap muscles (LSM) in typically developing five-year-old females as they swallowed boluses that differed in volume and consistency. Each participant completed several experimental swallowing tasks including swallowing four volumes (1, 3, 5, and 10 ml boluses) of water, pudding, cheese spread, barium liquid, and barium paste. These consistencies were chosen as they encompass those consistencies used during clinical and modified barium swallowing examinations. Analyses of data included measurement of the average duration of EMG records obtained from submental and laryngeal strap muscles during swallowing across each volume and consistency. These measurements were obtained using algorithms custom designed for MATLAB (v.5.1; The Mathworks, Inc., 1999). For each participant, data analyses yielded a mean duration for each muscle within each swallowing task. An analysis of variance (ANOV A) for repeated measures and subsequent post-hoc analyses were performed to determine the effects of bolus volume and bolus consistency on average duration of muscle activity during swallowing in children.