Wavelet analysis of the gut myoelectrical activity relationship with mechanical activity

The electroenterogram (EEnG) is the myoelectrical signal of the smooth muscle of the small bowel. This signal can be recorded through bipolar electrodes placed in the intestinal serosa. The objective of this study, is to determinate the relationship that exists between the electroenterogram and the pressure signal. Were taken 14 sessions of record of the myoelectrical signal. The pressure signal was recorded using a latex microballoon, implanted through surgery, in the same ring of the layer of circular muscle, in which the bipolar electrode was implanted. The signals were amplified and acquired simultaneously. The continuous wavelet transform was calculated (in its discrete model), using the Morlet´s wavelet. Eleven scales of frequency were chosen for the wavelet transform. The energy of the levels of frequency ν₂-ν₁₀ and the energy of the pressure signal reached high correlation coefficients (around 0.8). The greater means correlation coefficient (0.83) was obtained by levels ν₈-ν₉. Those levels correspond to the band of frequency 12.064-20.769 Hz. The levels ν₈-ν₉ contain the high frequency components, which correspond to spike burst. There aren´t significant differences among levels of frequency ν₂-ν₁₀. Therefore, the energy frequency levels ν₂-ν₁₀ can be used to represent intestinal motility indexes (IMIs).