Interpreting the sounds of swallowing: fluid flow through the cricopharyngeus.

The sounds of swallowing in normal subjects were recorded by means of a miniature accelerometer on the throat, simultaneously with videofluoroscopy of a modified barium swallow. Consistent correspondence was found between a rapid change in the acoustic spectrum of the accelerometer signal (the appearance of a region of energy prominence above 1,000 Hz) and bolus flow through the cricopharyngeus.