Cystometry is a measurement of pressure in the bladder during bladder filling and is done by introducing a tube into the bladder which is connected to an external pressure measuring device. While the bladder is filled it demonstrates NDO, measures the extensibility of the bladder wall, the pressure point at leakage and can be used to help evaluate filling sensation. When limited resources do not allow purchasing an electronic equipment, a cheap one channel cystometry device permits to gain valuable information. But interpretation is easier when bladder pressure measurement is combined with measurement of intrarectal/intraabdominal pressure as discussed below.