Biofeedback in rehabilitation of anal sphincter muscles

Biofeedback training is often used in rehabilitation of anal sphincter muscles and is a preferred method in pediatrics. It usually comprises the measurement of the myoelectric activity and/or the pressure with an intra-anal manometer. Here, a biofeedback system enabling audio- and visual monitoring of both myoelectric signals and intra-anal pressure is presented. The system was developed for pediatric feedback training, even for infants younger than five years. The pressure is measured with thin piezoelectric sensors positioned in-between EMG electrodes on an anal probe. The main advantages of this design is that it enables noninvasive measurement of myoelectric signals and that abdominal pressure is not affecting the results of pressure measurement during contraction of anal sphincters. High sensitivity can be achieved even at the beginning of the training when the produced force is very small in contrast to the myoelectric signal which decreases during training.