Tertiary esophageal contractions evoked by acoustical stimuli

"Spontaneous" tertiary esophageal contractions occur in a high proportion of healthy subjects. This study was carried out to investigate whether such contractions can be elicited by acoustical stimuli, to determine the threshold intensity at which contractions occur, and to find out how many of a sequence of equiintense tones at such a threshold intensity evoke contractile responses. Esophageal pressures were recorded 5, 10, and 15 cm above the lower esophageal sphincter, and swallowing was recorded by an electromyogram of the mylo-hyoid muscles. The results are summarized as follows: (a) All of 22 subjects exposed to 1000 Hz tones of intensities between 70 and 125 dBA responded with teritary contractions; their mean threshold intensity was 86.8 dBA +/- 3.0 SEM. Intensities that were 5 to 20 dBA higher were necessary to evoke contractions also in response to a second tone of a given intensity. (b) In 36 to 40 subjects exposed to 40 1000 Hz, 90 dBA tones tertiary contractions occurred in response to 47.2% of stimuli presented. (c) On repetitive stimulation, there was a significant decrease in number and amplitude of esophageal responses with an increasing number of stimuli. It is concluded that the esophagus takes part in the response system of the healthy organism to environmental stimuli.