This consists of asking the patient to take a deep breath in with the mouth closed and the nostrils pinched, and simultaneously looking with the laryngoscope at the throat. One looks in particular for collapse of certain portions of the airway. We believe that this reproduces what is happening during OSA episodes, but the implication of a positive Muller test is not well known. This is an overnight test that is done in special sleep centers. Multiple monitors are used to measure a variety of different physiological signals during sleep.
Airflow monitors keep track of how often and how long the apneic events last.
An apnea is defined as a cessation in breathing lasting 10 seconds or longer. One of the key findings in OSA is a drop in oxygen concentration. Movement of the chest wall is monitored to determine if the apnea is central or obstructive. Other types of sleep disorders are associated with leg movements, jaw clenching, and other characteristic movements. Sleep is divided into characteristic stages based on brain wave activity.