Abstract: An apparatus for measuring the micromotion of the wall of a hollow organ comprises: a catheter having a first end and a second end; an inflatable balloon disposed over the first end of the catheter with the balloon being fluid tightly sealed to the catheter at a position intermediate the first and second ends thereof; at least four electrodes affixed to an inner surface of the balloon, the electrodes being spaced apart from one another when the inflatable balloon is at least partially inflated; and a respective electrically conductive lead electrically connected to each of the electrodes, each lead having an electrically insulating cover thereover and each lead passing through said catheter and extending beyond the second end thereof. In use, the catheter with the deflated balloon attached is brought into the hollow organ, e.g., the bladder, and then the balloon is at least partially inflated with a liquid having a predetermined electrical resistivity.