Maximal static respiratory pressures in generalized neuromuscular disease.

Maximal static respiratory pressures were determined by a simplified method in a group of patients with neuromuscular disease and were more frequently abnormal than the vital capacity, maximal midexpiratory flow, or maximal breathing capacity. This method detected muscle weakness even in the presence of coexistent intrapulmonary disease and was helpful in evaluating dyspnea in these patients. Early in the disease, the maximal static respiratory pressures can be abnormal even though the results of spirometry are normal.