Small bowel motility: relationship between smooth muscle contraction and electroenterogram signal

A study is made to correlate the electrical and mechanical activity of the smooth muscle of the small bowel. Bioelectrical signal recording from the intestinal serosa (electroenterogram) comprises a slow wave (SW) and spike burst (SB), though only the latter reflects intestinal pressure. The electroenterogram and smooth muscle pressure are simultaneously recorded in the canine small bowel. Spectral and time series analysis of the electroenterogram are performed to establish those electrical parameters that best reflect intestinal pressure. The results reveal an underlying correlation between the estimated parameters of electrical activity and smooth muscle pressure. In addition, parameters derived from the spectral techniques were closely correlated to pressure events in the intestine, even more so than the variables directly acquired from the classical time domain analyses. Specifically, spectral energy above 2 Hz and mean frequency (both calculated from the biosignal periodogram), are parameters that identify intestinal pressure. The extrapolation of these spectral parameters to long time periods could serve to define a motility index (MI) from electrical gut activity. In this context, electroenterogram recording and analysis can contribute to solve problems inherent to manometric recording, though the need for surgical intervention restricts electrical methods to experimental or surgical studies.