Myofeedback: a new method of teaching breathing exercises in emphysematous patients

The diaphragm of the emphysematous patient is low and limited in its excursions, producing an increased functional residual capacity and decreased pulmonary ventilation. This report describes our experiences with a new technique for 1) the training of abdominal-diaphragmatic (A-D) breathing and 2) the relaxation of accessory respiratory muscles in emphysematous patients. Abdominal muscle contraction during expiration has been shown to increase diaphragmatic excursions and, hence, pulmonary ventilation. Use of this technique has been limited, however, because of the difficulty in learning this breathing pattern. Through continuous audio and visual feedback of myoelectric potentials (myofeedback) from abdominal muscles, 12 patients learned A-D breathing. The lower rectus abdominis muscle was found to be the most suitable muscle for obtaining the myoelectric potentials. Similarly, by providing the patients with myofeedback from their accessory muscles, they decreased the use of these muscles, thus increasing their respiratory efficiency. With myofeedback, patients appear to learn new breathing patterns effectively and in fewer sessions than with conventional procedures.