1.   As it swims, a fish creates a pressure wave that travels ahead of it.

2.   His last sensation was of pressure waves rippling against his body.

3.   Swallowing was indicated by characteristic pharyngeal pressure waves in the most proximal sidehole.

4.   The reference point for timing of swallows was taken from the onset of this pressure wave.

5.   The first step in the analysis consisted of determining the deglutitive or non-deglutitive nature of all oesophageal pressure waves.