LEARNED ACTIVATION OF THORACIC INSPIRATORY MUSCLES IN TETRAPLEGICS

The aim of this study was to determine whether tetraplegics can learn to activate accessory inspiratory muscles of the upper rib cage, and h ow this learning affects respiratory motion. Ten tetraplegics with les ional levels ranging from C-5 to C-7 were trained to increase the uppe r rib cage expansion during nine 20-min sessions. They were shown an e lectromyogram (EMG) feedback of the inspiratory muscles of the upper t horax and a signal indicating their current breathing phase (inspirati on or expiration). The subjects were instructed to increase EMG during inspiration and to decrease it during expiration. Analysis of varianc e with session and respiratory phase as factors showed that the subjec ts progressively learned to increase inspiratory EMG. Thoracic motion, tidal volume and minute ventilation were correlated with inspiratory EMG and tended to increase as a function of practice. These preliminar y results lend some support to the clinical use of EMG feedback in bre athing therapy aimed at increasing thoracic motion and preventing or r educing paradoxical breathing in tetraplegics.