[Dilator naris activity in relation to obstructive sleep apnea]

We evaluated the activity of dilator nasalis+ EMG (Electro-Myo-Graphy) and submental EMG during sleep in three patients with obstructive sleep apnea syndrome. Both EMG activities involved periodic changes which proved to be correlated with each other (r = 0.85). Apnea and hypopnea episodes always occurred at the nadir of these periodic changes. The activity of dilator nasalis+ EMG, as well as submental EMG, at the nadir of these periodic changes was significantly lower during REM (Rapid Eye Movement) sleep than non-REM sleep and also significantly lower during severe airway obstruction accompanied by paradoxical movements of thorax and abdomen. The correlation of this EMG activity with SaO2 or the duration of obstructive apnea was more remarkable in submental EMG than dilator nasalis+ EMG in the observed patients.