Control and Modulation of Respiration in Steinert's Myotonic Dystrophy1–3

Respiratory impairment in patients with Steinert's muscular dystrophy is known to lead to respiratory failure. Both the blunted chemical drive of breathing and the respiratory muscle weakness have been cited in the pathophysiology of premature death in these patients. To further assess the chemical control of breathing in these patients, we measured their respiratory responses to hypoxia (Weil's method), hyperoxia (Dejours' method), and hypercapnia (Read's method). In response to the stimuli from these respiratory centers, minute ventilation , tidal volume (Vt), respiratory frequency (F), mean inspiratory flow rate (Vt/Ti), and occlusion pressure (P0.1) were measured in 12 patients and in 12 normal persons matched to the patients on the basis of age, sex, and arm span. The patients were similar to the control subjects in occlusion pressure results. However, they differed significantly (P < 0.01) in ventilatory responses by a lower , lower Vt, higher F, and lower Vt/Ti in response to the hypercapnia and hy...