Polygraphic study of periodic breathing and hypersomnolence in a patient with severe hypothyroidism.

A 67-year-old woman with primary hypothyroidism, who had Pickwickian syndrome as well, was studied electrophysiologically. A polygraphic study with simultaneous recordings of electroencephalography, actograms of the abdominal walls, the mentum and the anterior neck, and electromyogram of the intercostal muscles revealed a cyclic appearance of apnea in the sleep phase and gasping preceding arousal, which, together with macroglossia and sleep in the sitting position, suggested a cyclic obstruction of the upper airway. The obstruction appeared responsible for both alveolar hypoventilation and disturbance of consciousness.