[Sleepiness and sleep apnea syndrome. Analysis of 188 questionnaires (102 patients and 86 controls)].

A questionnaire was given to 102 obstructive sleep apnea patients and 86 controls. A somnolence index was defined by averaging the scores of the answers to eleven questions concerning sleepiness. This index separated patients and controls (P < 0.0001). It was correlated with the apnea + hypopnea index (r = 0.32, P < 0.001), the body mass index (r = 0.45, P < 0.001) and with an objective measurement of sleepiness obtained from a modified multiple sleep latency test (r = -0.54, P < 0.001). Depending upon the current occupation, the tendency to fall asleep decreased in the following order: watching TV, passenger in a means of transport, reading, attending a show, attending a meeting, driving a car, and eating. This order is the same in patients and controls, irrespective of their "overall sleepiness". Thus, the circumstances of falling asleep are indicative of the severity of sleepiness.