Effect of bolus consistency on swallowing – does altering consistency help?

The influence of food bolus consistency on the pharyngeal wave during swallowing was investigated using a four-sensor manometry probe in 22 healthy volunteers. Pharyngeal pressures were recorded for 5 ml boluses of water, pudding and buttered bread via a manometry probe placed transnasally. The distal sensor was sited within the upper oesophageal sphincter (UOS); the three proximal sensors were then located 2, 4 and 6 cm above the UOS. The amplitude and timing of the swallow waveforms for pudding and buttered bread were recorded and compared with those for water. Increased bolus viscosity led to increased amplitude of the bolus wave and clearing contraction within the pharynx. In the UOS, increased bolus viscosity was associated with a larger pressure nadir (sub-atmospheric pressure) on opening and intra bolus pressure during transit. Bolus consistency also influenced the coordination of the swallow response with delayed pharyngeal clearance. The putative relevance of these findings to dietary modification for patients with neurological and neuromuscular dysphagia is discussed.