Respiratory and muscular analysis in patients with OSAS at different levels of ventilatory effort

Respiratory muscles activity is especially important in patients with obstructive sleep apnea syndrome (OSAS). A comparative study between patients and normal subjects during two protocols of increased and maintained respiratory efforts is presented. Respiratory pattern is evaluated by means of expired ventilation (V), respiratory frequency (f) and volume. Despite V being similar between groups, f increases more in patients than in normal subjects with effort. Three respiratory muscles are evaluated by means of spectral analysis of myographic signals: genioglossus, sternomastoid and diaphragm. The evolution of frequency parameters during the protocols show differences between groups in the muscular function especially with medium and high levels of effort.