Simplifying the Diagnosis of Obstructive Sleep Apnea

A recent Wisconsin study [1, 2] has shown that obstructive sleep apnea is an important public health problem. Questionnaires were mailed to state employees about snoring, witnessed apneas, and the like. Sleep studies were done on all patients who were habitual snorers and on 25% of nonhabitual snorers. The results indicated that 4% of middle-aged men and 2% of middle-aged women met the minimum diagnostic criteria for the obstructive sleep apnea syndrome [2].

This prevalence suggests that the syndrome is frequently undiagnosed, and it raises questions about how the condition should be identified. The current standard of practice in the United States is to use in-laboratory overnight polysomnography [3] that monitors many variables during sleep. These variables include the electroencephalogram, submental electromyogram, and electro-oculogram (all for sleep staging); respiratory airflow; respiratory effort; oxygen saturation; electrocardiogram; snoring; body position; and tibialis electromyogram (to detect nocturnal myoclonus). The precise contribution of each datum to the final diagnosis of sleep apnea is not well established. This imprecision has led to differences in currently recommended diagnostic practices between physicians in the United States [3] and in Europe [4, 5].

The possible redundancy of some of the data, along with the high cost of the test, has led to attempts to simplify the diagnostic strategy by, for example, only using oximetry [6-11]; however, the results have been conflicting. Some studies [7-10] have shown …