Noninvasive Urination-Desire Sensing Method Based on Bladder Bioimpedance Spectrum Analysis

For nursing overactive bladder syndrome in the lower urinary tract, it is important to understand the origins of urination-desire sensing during natural bladder filling. This study proposes a noninvasive urination-desire sensing method based on bioimpedance (BI) spectrum analysis. For BI measurement of the bladder, two excitation electrodes and two measurement electrodes are placed on the hypogastric surface of the body. The measurement system for BI provided a 0.2-mA alternating current with a 50-kHz frequency, which was sufficient to continuously measure the changes of the bladder during the various control stages of bladder filling. The results show that the higher-frequency spectral power (0.15–0.4 Hz) decreased ( p = 0.05) and the low-to-high frequency ratio significantly increased ( p = 0.001) during natural bladder filling for 12 healthy male volunteers. In contrast, the change in the lower-frequency spectral power (0.04–0.15 Hz) was insignificant. So to some extent, the method can be used to check the necessity to void for bladder, and assess neural regulation during bladder filling.