SLEEP-APNEA OF CENTRAL ORIGIN IN A CASE OF MYOTONIC-DYSTROPHY

We report the case of a 46-year-old male with myotonic dystrophy who d eveloped daytime hypersomnia and dyspnoea. After a therapeutic tracheo stomy, overnight polysomnographic studies were performed under three d ifferent ventilatory conditions. When the patient breathed spontaneous ly through a tracheal cannula, abnormal cyclical sleep increased and r apid eye movement (REM) sleep decreased markedly. The apnoea nad hypop noea index (AH index) was 35.1. When breathing spontaneously through h is normal airway, there were many instances of cyclical sleep, but few instances of deep sleep and no episodes of REM sleep. The AH index wa s 58. Under assisted ventilation the patient's sleep pattern was norma l. Our conclusion, therefore, is that these studies demonstrate the pa tient had sleep apnoea of central origin. (C) Harcourt Brace & Co. Ltd 1998.