Comparison of bio-impedance changes and EMG activity during daily events

A conventional method for measuring abdominal pressure involves the use of a fluid-filled rectal catheter. However, this method has some drawbacks, so it is limited to ambulatory urodynamics monitoring study. In this study, we proposed a novel method for estimating abdominal pressure in non invasive manner by changes in bio-impedance and electromyographic (EMG) signals. As a preliminary, we compared the bio-impedance changes and EMG activity during daily events, such as cough, sneeze and lumbar movement, while the abdominal pressure increased. The correlation coefficients between changes in bio-impedance and EMG signals, according to increases in abdominal contractions, were 0.72, 0.96, 0.90, 0.84 and 0.78 for the weak, strong, stronger, vigorous and maximal contraction, respectively. Also, daily activities such as coughing, sneezing and conversation, were sensitively monitored by measuring the change in amplitude of the bio-impedance signals, whilst EMG signals could not be used to detect these activities; therefore, the bio-impedance method is a more useful means of non-invasively measuring the changes in the abdominal pressure for urodynamics monitoring.