MESAM4 evaluated nocturnal respiration disturbances in myasthenia gravis

Twenty-eight treated patients with myasthenia gravis (MG) (Osserman's scale: ocular form-12 cases, mild generalized form-5 cases, medium generalized form-10 cases, free of symptoms after thymectomy-1 case) were examined with MESAM4. Typical sleep apnea syndrome (SAS) patterns were observed in 12 subjects, mild saturation undulation without respiratory noises and without heart rate changes in 7 (3 of them also produced the SAS pattern) and irregular nonspecific changes in 3. The average vital capacity in SAS patients was 2556 (SD = 1166) ml, and in patients without MESAM4 abnormality 1629 (559) ml, P < 0.05. The average of oxygen saturation minima in SAS patients was 87.6 (3.6) %, in patients without MESAM4 abnormality 91.5 (1.8), P < 0.01. We conclude that there is no relation between any clinical parameter of MG and the occurrence of nocturnal respiratory disturbances. The risk factors of the occurrence of sleep respiratory disturbances in MG are similar to those of the non-myasthenia population although the incidence of this condition in MG is higher.